UNIVERSITY OF GHANA
SCHOOL OF BIOLOGICAL SCIENCES
PROCESS DEVELOPMENT AND PRODUCT CHARACTERIZATION OF A
FERMENTED RICE-BASED BABY FOOD
BY
VICTORIA YEMOTELEY ODOI
(10253156)
THIS THESIS/DISSERTATION  IS SUBMITTED TO THE
UNIVERSITY OF GHANA,LEGON
IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF
MASTER OF PHILOSOPHY (MPHIL) FOOD SCIENCE DEGREE
DEPARTMENT OF NUTRITION AND FOOD SCIENCE
JULY, 2016
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iDECLARATION
I, Victoria Yemoteley Odoi, do hereby declare that, except for other people’s works which have
been cited and duly acknowledged, this work is my original research and this dissertation has not
been presented for another degree elsewhere, either in part or as a whole.
……………………………..                                                                     Date: …………………..
Victoria Yemoteley Odoi
(Student)
………………………………                                                                 Date: …………………....
Prof. Firibu Saalia
(Main supervisor)
………………………………                                                                 Date: ……………….…..
Dr. Maame Yaakwaah Blay
(Co-supervisor)
…………………………….                                                                     Date: …………………..
Prof. Paa-Nii Johnson
(Co-supervisor)
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DEDICATION
I dedicate this work to my God Almighty, for His grace, favour, guidance and blessings
throughout this work. I also dedicate this research work to my entire family, most especially to
my mother, Mrs. Elizabeth Kate Nana Adjua Faidua Odoi, for all her love and sacrifices; I love
you so much mum! Thanks for pushing me this far and believing in me.
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ACKNOWLEDGEMENT
My sincere gratitude goes to Almighty God for sustaining me throughout this research.  I am
much grateful to Prof. Saalia for his guidance, criticisms and immense intellectual contributions
to this work. I cannot thank you enough, Sir, God richly bless you! My heartfelt appreciation also
goes to Dr. Maame Yaakwaah Blay for her intellectual assistance and support in this work.
I am appreciative of Prof. Paa-Nii Johnson (CSIR), Dr. John Manful (AfricaRice), Prof.
Francesco Bonomi (DEFENs, University of Milan-Italy), Prof. Stefania Iametti (DEFENs,
University of Milan), Dr. Mauro Marengo (DEFENs, University of Milan-Italy) and Michela
Collauto (graduate student, DEFENs, University of Milan-Italy) for the financial and technical
support which has driven this project to a successful end. A big thank you to you all.
I acknowledge in a very special way the support of my husband, Raymond Otu-Amanortey;
thanks for all the love, understanding and assistance. Worthy of my appreciation is Dr. Augustine
Donkor, for always lending a helping hand in my time of need during this work. A final thank you
to my classmates: Sylvia, Farida, Eurydice, Humphrey, Richard, Roland and Isabella. God bless
you all.
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TABLE OF CONTENTS
DECLARATION ...............................................................................................................................i
DEDICATION..................................................................................................................................ii
ACKNOWLEDGEMENT ...............................................................................................................iii
TABLE OF CONTENTS.................................................................................................................iv
LIST OF TABLES..........................................................................................................................vii
LIST OF FIGURES .......................................................................................................................viii
LIST OF APPENDICES..................................................................................................................xi
ABSTRACT....................................................................................................................................xii
CHAPTER ONE ...............................................................................................................................1
INTRODUCTION ............................................................................................................................1
1.1 Background and Study Rationale ............................................................................................1
1.2. Main Objective of Study.....................................................................................................6
1.2.1 Specific Objectives ...........................................................................................................6
CHAPTER TWO ..............................................................................................................................7
LITERATURE REVIEW .................................................................................................................7
2.1 Introduction .............................................................................................................................7
2.2 Categories of Baby Foods in Ghana........................................................................................8
2.3 Nature and Composition of Rice as a Feeding Grain ........................................................10
2.4 Rice Varieties, Their Production and Applications in Food..............................................12
2.5 Nutritional Properties of Rice and Its Functionality in Food ............................................14
2.5.2 Other nutrients in rice .....................................................................................................18
2.5.4 Protein Digestibility of Rice ...........................................................................................20
2.6 Technologies Used in Processing of Rice Paddy ..................................................................20
2.7 Industrial Technologies used in the Food Industry to Produce Ready-to-Eat Cereal–Based
Products.......................................................................................................................................22
2.7.1 Traditional Processing of Cereal Food Products ............................................................23
2.7.2 Industrial Processing of Cereal Food Products...............................................................26
2.8 Product Development Strategies ...........................................................................................27
2.9 Sensory Evaluation of Developed Products ..........................................................................28
CHAPTER THREE ........................................................................................................................33
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vMATERIALS AND METHODS....................................................................................................33
3.1 Rice Samples .........................................................................................................................33
3.2 Parboiling Procedure .............................................................................................................33
3.3 Dough Preparation and Fermentation ...................................................................................34
3.4 Drum-Drying Process............................................................................................................35
3.5 Analytical Procedures ...........................................................................................................36
3.6 Proximate analysis.................................................................................................................36
3.6.1 Moisture content .............................................................................................................36
3.6.2 Water activity .................................................................................................................36
3.6.3 Protein Solubility and Gel Electrophoresis Pattern ........................................................37
3.7 In vitro Protein Digestibility .................................................................................................38
3.8 Colour Determination............................................................................................................39
3.9 Pasting Properties ..................................................................................................................40
3.10 Thiol determination .............................................................................................................40
3.10.1 Accessible Thiols..........................................................................................................40
3.10.2 Total Thiols...................................................................................................................41
3.11 Water Absorption Capacity and Water Solubility Index ....................................................41
3.12 pH and Titratable Acidity....................................................................................................42
3.13 Starch Digestibility..............................................................................................................42
3.14 Sensory Evaluation of Fermented Rice-Based Products.....................................................44
3.14.1 Electronic Nose Measurements ....................................................................................44
3.14.2 Electronic Tongue Measurements ................................................................................45
3.14.3 Quantitative Descriptive Analysis (QDA)....................................................................46
3.15 Statistical Analysis ..............................................................................................................48
CHAPTER FOUR...........................................................................................................................50
RESULTS AND DISCUSSION.....................................................................................................50
4.1 Physicochemical Properties of the Drum-dried Fermented Baby Food................................50
4.1.1 Colour .............................................................................................................................50
4.1.2 pH and Total (or Titratable) Acidity...............................................................................53
4.1.3 Proximate composition comparing physico-chemical properties of dough with final
products ...................................................................................................................................55
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4.2 Functional Properties of Baby Food Products.......................................................................59
4.2.1 Hydration properties: ......................................................................................................59
4.2.2   Pasting Properties .........................................................................................................62
4.2.3   Pasting Profile...............................................................................................................66
4.3.1 Protein Solubility............................................................................................................68
4.3.2 Thiol Accessibility Studies.............................................................................................71
4.3.3 Sodium Dodecyl Sulfate Polyacrylamide-Gel Electrophoresis (SDS-PAGE) Patterns of
Rice Proteins............................................................................................................................74
4.4 In vitro Digestibility Studies .................................................................................................76
4.4.1 Protein Digestibility by pepsin and pancreatin...............................................................76
4.4.2 Starch Digestibility and Free Sugars Determination ......................................................79
4.5 Sensory Evaluation................................................................................................................82
4.5.1 Quantitative Descriptive Analysis ..................................................................................83
4.5.2 Sensory evaluation using E-sensors (electronic nose and electronic tongue) ..............103
4.5.3 Principal Component Analysis (PCA)..........................................................................104
CHAPTER FIVE ..........................................................................................................................113
CONCLUSION AND RECOMMENDATION............................................................................113
5.1 Conclusion...........................................................................................................................113
5.2 Recommendation ....................................................................................................................114
REFERENCES .............................................................................................................................116
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LIST OF TABLES
Table 1: List and characteristics of electronic tongue detecting sensors....................................... 32
Table 2a: Estimated means ± standard deviations of the tristimulus colour values...................... 52
Table 2b: Estimated means ± standard deviations of the tristimulus and total colour
difference........................................................................................................................................ 53
Table 3: Proximate composition table comparing fermented dough and final baby food products
from milled and parboiled rice....................................................................................................... 57
Table 4: Pasting characteristics of fermented rice-based milled and parboiled
products..........................................................................................................................................65
Table 5: Protein solubility of drum-dried fermented rice dough (baby food)............................... 70
Table 6: Estimated mean values for RDS, SDS and Predicted Glycaemic Index of fermented rice-
based products...............………………………………………………………..…………………80
Table 7: List of sensory descriptors and definitions for fermented rice-based products (powdery
form)………………………………………………………............................................................90
Table 8: List of sensory descriptors and definitions for fermented rice-based products (re-
constituted form)………………………………………………………………………….…........99
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LIST OF FIGURES
Figure 1: The Structure of the Rice…………………………………………................................11
Figure 2a: A simple viscosity-temperature profile obtained using a Rapid-Visco
Analyzer........................................................................................................................................ 16
Figure 2b Improved method of parboiling paddy rice in Ghana……………………………….. 22
Figure 3: A portable electronic nose (PEN 2)...............................................................................31
Figure 4: Operational procedure of the PEN 2 electronic nose showing interactions between array
of sensors and volatiles from test samples....................................................................................31
Figure 5: A simple electronic tongue (Taste Sensing System SA 402B)……………….…...... 32
Figure 6: A flow chart showing the preparation of fermented rice-based baby food.................. 35
Figure 7: pH and titratable acidity (% TA as lactic acid) of milled and parboiled fermented rice-
based baby food product as a function of fermentation................................................................54
Figure 8a: Moisture content and water activity of milled fermented rice-based baby food products
as a function of fermentation……………………………………………………………........... 58
Figure 8b: Moisture content and water activity of parboiled fermented rice-based baby food
products as a function of fermentation………………………………………….........................58
Figure 9a: Effect of fermentation time and parboiling treatment on water absorption index
(WAI)…………………………………………............................................................................60
Figure 9b: Effect of fermentation time and parboiling treatment on water solubility index
(WSI)............................................................................................................................................62
Figure 10: Microviscoamylograph showing pasting profile of fermented milled rice-based
product..........................................................................................................................................67
Figure 11: Microviscoamylograph showing pasting profile of fermented parboiled rice-based
product..........................................................................................................................................67
Figure 12: Protein solubility in different buffer systems for drum-dried milled fermented rice
samples.........................................................................................................................................70
Figure 13: Protein solubility in different buffer systems for drum-dried parboiled fermented rice
samples........................................................................................................................................71
Figure 14: Accessible thiols in proteins of fermented milled rice-based baby food products.
.....................................................................................................................................................73
Figure 15: Accessible thiols in proteins of fermented parboiled rice-based baby food
products.......................................................................................................................................73
Figure 16: SDS-PAGE patterns of proteins in milled fermented rice-based baby food products
................................................................................................................................................... 75
Figure 17: SDS-PAGE patterns of proteins in parboiled fermented rice-based baby food
products..................................................................................................................................... 76
Figure 18: Effect of processing on the in vitro protein digestibility of drum-dried fermented
milled rice-based baby food …………………………………………………………………...78
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Figure 19: Effect of processing on the in vitro protein digestibility of drum-dried fermented
parboiled rice-based baby food................................................................................................. 78
Figure 20: Free sugars present in fermentation milled rice-based product............................... 81
Figure 21: Free sugars present in fermentation milled rice-based product............................... 82
Figure 22: Sensory profile showing appearance attributes of fermented milled rice-based products
(powdered form).........................................................................................................................86
Figure 23: Sensory profile showing appearance attributes of fermented parboiled rice-based
products (powdered form)......................................................................................................... 86
Figure 24: Sensory profile showing aroma attributes of fermented milled rice-based products
(powdered form).........................................................................................................................87
Figure 25: Sensory profile showing aroma attributes of fermented parboiled rice-based products
(powdered form)........................................................................................................................ 87
Figure 26: Sensory profile showing flavour attributes of fermented milled rice-based products
(powdered form)..........................................................................................................................88
Figure 27: Sensory profile showing flavour attributes of fermented parboiled rice-based products
(powdered form) ….................................................................................................................... 88
Figure 28: Sensory profile showing texture attributes of fermented milled rice-based products
(powdered form)........................................................................................................................ 89
Figure 29: Sensory profile showing texture attributes of fermented parboiled rice-based products
(powdered form) ….................................................................................................................... 89
Figure 30: Sensory profile showing appearance attributes of fermented milled rice-based products
(re-constituted form) .................................................................................................................. 95
Figure 31: Sensory profile showing appearance attributes of fermented parboiled rice-based
products (re-constituted form)..................................................................................................... 95
Figure 32: Sensory profile showing aroma attributes of fermented milled rice-based products (re-
constituted form)........................................................................................................................ 96
Figure 33: Sensory profile showing aroma attributes of fermented parboiled rice-based products
(re-constituted form)……………………………………...............................................……… 96
Figure 34: Sensory profile showing flavour attributes of fermented milled rice-based products (re-
constituted form)........................................................................................................................ 97
Figure 35: Sensory profile showing flavour attributes of fermented parboiled rice-based products
(re-constituted form)…............................................................................................................... 97
Figure 36: Sensory profile showing texture attributes of fermented milled rice-based products (re-
constituted form)…..................................................................................................................... 98
Figure 37: Sensory profile showing texture attributes of fermented parboiled rice-based products
(re-constituted form)…………………………………...................................................………..98
Figure 38a: Loading plot of aroma attributes (powdered samples)……………………........... 107
Figure 38b: Score plot of aroma attributes (powdered samples)………………………........... 107
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xFigure 39a: Loading plot of flavour attributes (powdered samples)………………….............108
Figure 39b: Score plot of flavour attributes (powdered samples)………………….................108
Figure 40a: Loading plot of aroma attributes (re-constituted samples).……..………............ 109
Figure 40b: Score plot of aroma attributes (re-constituted samples)..……..…………............109
Figure 41a: Loading plot of flavour attributes (re-constituted samples)..……..………..........110
Figure 41b: Score plot of flavour attributes (re-constituted samples)..….…..……..…...........110
Figure 42a: Loading plot for aroma attributes of samples using the electronic nose…..........111
Figure 42b: Score plot for aroma attributes of samples using the electronic nose…..............111
Figure 43a: Loading plot for flavour attributes of samples using the electronic tongue.........112
Figure 43b: Score plot for flavour attributes of samples using the electronic tongue….........112
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xi
LIST OF APPENDICES
Appendix A............................................................................................................................143-155
Appendix B............................................................................................................................156-157
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xii
ABSTRACT
Oryza glaberrima is a local rice variety that is native to West Africa. Its tough texture and
robustness produces milled rice with a large quantity of broken grains when dehusked (polished)
accounting for the huge gap in quality. Consequently, imported rice is much more consumed in
Ghana than locally cultivated and milled rice. The objective of this study was to add value to
local rice by developing and characterizing a rice-based baby food from low grade locally milled
and parboiled rice by using simple traditional food processing technologies of fermentation and
size reduction. A 2χ 4 factorial design  for  a local rice cultivar (milled and parboiled) and
fermentation time (0, 12, 24 and 48 hours) was used to develop drum dried, pre-cooked
fermented rice product as baby food. The physico-chemical, functional and sensory characteristics
of the drum dried fermented rice product were evaluated.
The drum dried products had moisture content of 5.88 -7.84 % and 5.12 - 11.2 % for milled and
parboiled rice respectively. Fermentation time and milling method influenced the physical
characteristics of the final products. Parboiled products were lighter in colour (∆E= 4.27 - 2.69)
and showed significantly lower pH values (4.13-3.38) with corresponding higher total acidity
values (0.046-0.150)% lactic acid as fermentation time increased. Lower water absorption index
(WAI) values and corresponding higher water solubility index (WSI) values were recorded for
parboiled products as fermentation progressed due to the incidence of degraded starch molecules.
The SDS-PAGE patterns of rice proteins showed three bands corresponding to proteins of
molecular weights 14kDa, 30kDa and 45kDa respectively in both milled and parboiled rice
samples in all three buffer systems. Protein solubility increased with fermentation time until
twelve hours then it decreased through to 48 hours fermentation time. Parboiling and increasing
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fermentation time also significantly favoured the formation of accessible protein thiols. Pasting
profiles of products indicated that milled products had a higher tendency to disintegrate as well as
undergo retrogradation and thus were more likely to give thinner gruels when hot water was used
for re-constitution than parboiled rice. The 48-hour fermented products from both milled and
parboiled rice exhibited the highest protein and starch digestibilities. Sensory profiles revealed
altering intensities of sensory attributes of appearance, aroma, flavour, aftertaste and texture
(mouth feel and touch sensation) using powdered and re-constituted forms of the eight fermented
milled and parboiled rice-based products. Parboiled samples were described as more fermented,
rich, sour with sour after-taste as fermentation time progressed by the quantitative descriptive
analysis (QDA). Principal component analysis (PCA) scores were used to classify baby food
products based on aroma and flavour from quantitative descriptive analysis (QDA) data as well as
e-sensing measurements(electronic nose and tongue). These findings suggest that local rice would
be very useful as a baby food product and demonstrates the function of quantitative descriptive
analysis and e-sensing in evaluating and identifying product attributes that could be essential to
consumers and food processors.
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1CHAPTER ONE
INTRODUCTION
1.1 Background and Study Rationale
Rice is one of the most universally consumed grains around the world (Adeniran et al., 2012;
Boboye & Daramola, 2011; Amissah et al., 2003). In Ghana, its consumption has steadily grown
over the years (Tomlins et al., 2005, Adu-Kwarteng et al., 2003). CARD (2010) reported a rise in
the annual per capita consumption of rice in Ghana from 12.4kg/person to 20kg/person from 1980
to 2005. This figure doubled to 30kg/person by 2009 with a projected estimate of 63kg/person by
2015 (USAID, 2009). However, more than half of all the rice consumed in Ghana is imported
(Kranjac-Berisavljevic et al., 2003).
Rice is mainly composed of carbohydrates (about 75-80%), protein (about 7%) and some
minerals and vitamins B1, B2 and B3 (Oko et al., 2012). Because the main carbohydrate portion
of rice is starch (Deepa et al., 2010), it contributes to the body’s energy needs (Ratnayake
&Jackson, 2008) when consumed. The unique properties of rice starch have increased its
application in many products especially gluten-free products. Rice starch has a high glycaemic
index indicating high digestibility (Mir et al., 2013); one reason why it is incorporated in most
processed shelf stable infant cereal mixes and blends. A number of research studies on rice starch
digestibility on infant nutrition have been reported (Dreher et al., 1984; Fernandez-Artigas et al.,
2001). Rice proteins constitute the next most abundant nutrient in rice after starch. The proteins in
rice are of a very good quality (Juliano, 1985). Rice protein has also been found to have a high
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2digestibility (Ramirez-Jimenez et al., 2003). Like all cereals, rice is also rich in some minerals.
These include the macrominerals; calcium, magnesium and phosphorus. Micronutrients such as
iron, zinc, copper and manganese are present in trace amounts (Yousaf, 1992).  Adu-Kwarteng et
al. (2003) reported that local rice varieties have a higher nutritional content as compared to their
foreign counterparts based on a study conducted involving ten local varieties in Ghana. However,
local rice continues to suffer low patronage.
Globally, there are two commonly cultivated rice varieties: Oryza sativa and Oryza glaberrima
(ODI, 2003). In West Africa, the Oryza glaberrima, also known as African rice (AfricaRice,
2010) is cultivated and constitutes most of the locally produced rice in Ghana. Oryza sativa is
native to Asia and it is the main variety imported into the country. These two varieties are among
the few domesticated types that are cultivated out of the existing twenty one different wild species
of rice belonging to the genus Oryza (Juliano, 1985; Santos et al., 2013).Severallocal rice types
(Oryza glaberrima)are cultivated locally and they include Vionor, Emokokoo, Togo marshall,
Amavi, Abodwese, Emofitaa, Abibifoomo and Mui (Adu-Kwarteng et al., 2003). However, the
post-harvest handling of rice in Ghana is inefficient and leads to poor quality rice. Raw rice grains
are first harvested as paddy (raw rice) and dried to moisture content below 14% (usually 12-14%
moisture content) then de-husked to obtain brown rice, broken de-husked rice and husk (chaff). In
Ghana, the paddy may be processed by parboiling before milling or by raw milling, with the
former representing about 46% of locally produced rice (Tomlins et al., 2005). Parboiling is a
process that involves soaking, steaming and drying of the paddy before milling (de-husking or
polishing). The soaking time ranges from a few hours to about three days and in certain situations
warm water is used for this process. The essence of the soaking process is to allow the paddy to
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3imbibe as much water as possible to eventually reduce the amount of brokenness during milling
(Ayamdoo et al., 2013). Although parboiling has reported benefits such as increasing the nutrient
density of rice, the procedure brings about a characteristic strong flavour, discolouration of grains,
firmer grain texture and prolonged cooking time and these features are undesirable. On the other
hand, raw milling of the husked rice, where the pericarp, tegmen and aleuron layer are removed
produces the preferred white rice which may be whole or broken. Frequently, the percentage of
broken rice in locally milled rice is unacceptably high, leading to low grade or poor quality
product.
Rice is graded on the basis of the assessment of certain quality characteristics: physical attributes,
physicochemical qualities and the organoleptic characteristics. Grading of rice ranges from Grade
1 (premium) to Grade 5 (least in quality); this may however differ slightly from country to
country. For instance, according to Ghana Standards Authority, most of the locally produced rice
fall under the category 4.7 while USAID (2009) reported that 83% of domestic rice production
falls within grade 5.  Milling of most of the local varieties produces high amounts of broken
(about 13.60-32.70%) (Diako et al., 2010). These poor quality attributes of local rice consisting of
mostly broken explains consumers’ low patronage for this rice type.
In order to add value and increase the overall acceptability and utilization of the poor quality local
rice, basic food processing operations such as fermentation and size reduction could be applied.
Size reduction transforms the physical properties and opens up further options for the food
application of rice. For instance, broken rice is converted into flour which can be used to produce
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4baby foods or extruded into snacks and breakfast cereals or even used as a coating. Fermentation
is also a popular traditional processing technique applied to several food crops, particularly
cereals in Ghana. It is used in the development of a popular traditional complementary food,
‘koko’, which is a thin cereal porridge commonly prepared from maize, sorghum or millet. Also,
there have been several publications on other fermented cereal-based foods in Ghana (Mensah et
al., 1991; Annan et al., 2003; Blandino et al., 2003; Asante et al., 2013). In their study, Annan et
al. (2003) pointed out that spontaneous fermentation of corn dough used in the production of Ga
kenkey produced acids including 75 other compounds that contributed to the product’s aroma
profile. Strong evidence exists that the presence of these acids in fermented foods disallows the
growth of food pathogens and prolongs shelf life (Steinkraus, 1996; Oyewole, 1997;
Deshpande,2000; Beaumont, 2002; Annan et al., 2003; Kalui et al., 2009).Fermented rice, though
not very common in Africa has reported frequent use in many forms in Asia; ‘dosa’ (rice pan
cake), ‘sake’ (rice wine), ‘idli’ (steamed rice balls) and ‘khanom jeen’ (fermented rice noodles)
(Soni et al.,1985; Wantanabe et al., 1998; Nagaraju & Manohar, 2000; Keatkrai & Jirapakkul,
2010).
Apart from the variation in dishes, fermentation has also been found to increase the nutrient
quality, for instance, the availability of lysine in rice (Hamad & Fields, 1979) and modify the
flavor profile of the product. In Africa, a study by Kabeir et al. (2004) improved the nutritional
value of ‘medida’, a thin porridge made from fermented rice used as complementary food in
Sudan while in Nigeria, Boboye & Daramola (2011) regulated the genes of the microorganism
Micrococcus luteus for the synthesis of glucose and protein during the fermentation of ‘Igbimo’,
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5an Oryza sativa variety of Nigerian rice. However, in Ghana, use of naturally fermented rice for
complementary or other foods has not yet been established.
The otherwise small market for low grade rice can be transformed by using a simple fermentation
process to produce a rice-based food product that requires size reduction such as complementary
or baby food. Complementary foods are important to the nutrition and healthy growth of babies in
the age group between 6 months and 2 years. They offer the major nourishment to infants
alongside breast feeding from six months to two years (Oyarekua et al., 2011). This is one of the
most vulnerable periods in the child’s life because at this stage the infant needs adequate nutrients
for good health and development. Consequently malnutrition is prevalent among infants in most
third world countries (UNICEF, 1990). In these countries most of the traditional complementary
foods are usually low in essential micronutirents, protein of high biological value and particularly
energy because they are often consumed in much diluted quantities (Kapil, 2000), leading to
growth deficits (WHO/UNICEF/ICCIDD, 2001). Additionally, a number of studies on the usage
of α-amylase-treated complementary foods to increase nutrient uptake by infants have been
recounted (Moursiet al., 2003; Chakravarthi & Kapoor, 2003; Den Besten et al., 1998). Owino et
al. (2007) confirmed that the incorporation of α-amylase in a cereal-legume complementary food
blend improved its acceptability when a thinner porridge consistency was obtained from the
blend. This demonstrates that α-amylase positively affect the final product acceptability when
added before or during fermentation process (Mok, 1992).
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6There is a pressing need to improve the value of local rice varieties in Ghana. Thus, besides
reduction of postharvest losses, many food processing methods can be used to solve the quality
problems associated with locally produced rice which are usually branded low grade. The use of
simple technologies such as size reduction and fermentation in the presence of alpha amylase to
produce an easily digestible baby food might tremendously improve the market value of locally
milled, low grade rice.
1.2. Main Objective of Study
The main objective of this study was to develop and characterize a fermented rice-based baby
food using low grade locally milled rice.
1.2.1 Specific Objectives
The specific objectives of this study are to:
1. develop a process for the production of a pre-cooked, ready-to-eat fermented rice-based
baby food.
2. determine the physicochemical changes of the fermented rice-based dough and final
product.
3. determine the functional properties of the final product.
4. determine the starch digestibility and protein digestibility of the final product.
5. evaluate the sensory attributes of the product.
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7CHAPTER TWO
LITERATURE REVIEW
2.1 Introduction
Ready-to-eat baby foods have recently become very popular in the last two decades because
mothers have become increasingly busy. The driving force of the continuous growing purchase of
these accessible baby foods is convenience. ‘Cerelac’, ‘Beechnut’ and ‘Purity’ are amongst the
commonly recognized baby food brands in the country. Most of these baby food brands are
cereal-based, may or may not contain milk and are reconstituted before feeding to baby. In Ghana,
cereals such as maize, sorghum and millet are locally fermented and used in the preparation of
porridges to feed weaning infants at home. These porridges have been reported as thin, dilute and
lack all the nutrients crucial to the proper development of growing babies (Lartey et al., 1999).
Over the years, a number of researchers have studied possible ways of improving the nutrient
density of these cereal-only baby food blends (Afoakwah et al., 2010; Saalia et al., 2012). Some
findings have suggested a combination of cereals with other protein-rich sources such as dry fish
powder and legumes including cow pea, soy bean, groundnut and melon seeds (Egoulety, 2002;
Amankwah et al., 2009). Lartey et al. (1999) reported a study that was conducted in Ghana by
UNICEF and Ministry of Health, Nutrition Department to develop ‘Weanimix’, a baby food blend
made up of maize, cowpea or soy bean and groundnut. Much of these published works have
centered on the use of fermented maize as the cereal base-meal in baby food production.
However, the use of tubers including sweet potato and yam as carbohydrate and other nutritional
sources for infant foods in Ghana and other African countries have also been reported (Nnam,
1999; Amagloh et al., 2012).
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8Rice flour has been enlisted as part of the list of ingredients in many ready-to-eat baby food
products attributable to the desirable properties of this cereal grain. There is however paucity of
data on the source of these rice flours suggesting that few of these rice types belong to local rice
varieties. Elsewhere in Sudan, Kabeir et al. (2004) suggested a formulation that improved the
nutritional value of ‘medida’, a fermented brown rice flour porridge also used as food for weaning
infants. Though the cereal-base used in this case was fermented rice, it was also not a local
variety. The use of fermented rice is not popular in Ghana and utilizing local rice as a main
cereal-base meal in the production of a ready-to-eat infant food is yet to be studied.
2.2 Categories of Baby Foods in Ghana
Baby foods are semi-solid foods given to infants from six months until they attain age two. These
foods may be home-made or available commercially in ready-to-eat or ready-to-use formulae.
Although these foods may contain a mishmash of various food types sometimes including pureed
meat, fish, fruits and vegetables, cereals normally form the base meal though they may at certain
times serve as added ingredients (Lartey et al., 1999; Odumodu, 2007). Ready-to-eat baby foods
could be classified based on their base-ingredients and these include milk-based infant foods,
infant cereals with or without milk, baby biscuits, fruit-based baby food, dairy-based desserts, and
mixtures of pureed fruits, vegetables, fish and meat (USFDA, 1994). These baby foods may be
liquid or solid in the form of dry powders that could be reconstituted with water or milk to make
the food soft or molten in a way that the infant can easily swallow or chew. Ready-to-eat infant
cereals that are common on the Ghanaian local market have not been reported to be sourced from
the local variety rice market even when rice is enlisted as part of the incorporated ingredients.
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92.2.1 Cereal-based baby foods
Cereals are the first source of food locally used for complementary feeding in developing
countries. Maize, millet and sorghum are cereals from which ‘koko’; a common home-made
porridge is prepared for feeding infants in Ghana. Many studies have demonstrated improved
nutritional properties of cereal-based infant foods to which non-cereals such as legumes and sweet
potato have been added (Lartey et al., 1999; Afoakwah et al., 2010; Saalia et al., 2012).
Amankwah et al. (2009) investigated maize-soybean blends and the effect of fermentation and
malting on their viscosities. Muhimbula et al. (2010) conducted a study which involved the
formulation of complementary food from a combination of cereals (maize, sorghum and finger
millet) and legumes (cow pea and green peas) in Tanzania and evaluated their sensory attributes.
Saalia et al. (2012) developed and evaluated low viscosity porridge (‘koko’) prepared by co-
fermenting maize flour with millet malt to be used for complementary feeding. Amagloh et al.
(2012) studied the carbohydrate composition, viscosity, solubility, and sensory acceptance of
maize-based and sweet potato-based complementary foods and found that the formulation of the
latter showed significant nutritional benefits. Results from these studies have shown that there is a
strong inclination to the frequent use of fermented maize in complementary feeding which is
perhaps driven by the availability, rheological properties and favourable sensory attributes of this
cereal which have been handed down through generations over the years in the sub-region.
Another important cereal that has reported use in infant feeding is rice (Amankwah et al., 2009).
Typically, rice flour is produced from rice grains that are broken or very small in size.  In recent
times, the use of fermented rice for varied products has been investigated (Nicolau et al., 2011).
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In the southern part of China, Lu et al. (2003) examined the influence of fermentation of rice used
to produce noodles and concluded that favorable sensory properties were attained. In most Asian
countries, complementary foods are usually rice-based for instance in the Philippines (Perlas &
Gibson, 2012). In their study, Perlas & Gibson (2012) used soaking to enhance the bioavailability
of iron and zinc in rice-based complementary foods used in the Philippines.
The benefit of using fermented rice is that it retains its nutrients even when used to develop
products that go through heat processing such as ready-to-eat food products (Tongnual & Fields,
1979). It is possible that rice is usually incorporated in several complementary cereal mixes for
this reason and also because of its hypoallergicity, bland taste and digestibility (Lu et al., 2003).
2.3 Nature and Composition of Rice as a Feeding Grain
2.3.1 Structure of the Rice Grain
The rice grain belongs to the grass family. It is usually harvested as paddy rice. The paddy is
either parboiled before milling or the raw paddy is milled directly after harvesting. According to
Li (2004) the structure of the rice grain is made up of fundamentally, the husk and the caryopsis
(brown rice). The caryopsis is considered as the ‘fruit’ part of the rice grain and constitutes the
bran which consists of the pericarp, aleurone layer and tegumen; the nutrient-rich embryo and the
starchy endosperm.  The bran constitutes the outer layer of the grain and is rich in fibre. The
lemmas and palea are clutching outer coverings that enclose and protect the fruity caryopsis
during grain development (Krishnan & Dayanandan, 2003). According to the same authors, the
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rachilla, sterile lemma and radicle are related structures that form part of the rice spikelet (Juliano
&Goddard, 1986).Figure 1 below shows the structure of the rice grain.
Figure 1 The Structure of the Rice Grain
Source: www.riceweb.org/planthtm. Accessed 27th January, 2015.
2.3.2 Rice Composition
Rice is mostly composed of starch (about 80%), proteins (7%) and little fat (about 1.5 -1.7%)
(Juliano & Goddard, 1986).  The protein quality of rice is good because it contains all the
essential amino acids (Kabeir et al., 2003). It is also rich in minerals such as phosphorus (P),
potassium (K), calcium (Ca), sodium (Na), iron (Fe) and zinc (Zn). Rice is also a good source of
the B vitamins; thiamin, niacin, riboflavin, cobalamin (Boboye & Daramola, 2011). Most of the
nutrients in rice are concentrated in the bran.
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2.4 Rice Varieties, Their Production and Applications in Food
Oryza sativa and Oryza glaberrima are the two main cultivated species of rice worldwide (ODI,
2003). The Oryza glaberrima is native to West Africa (Djedatin et al., 2011) and constitutes the
local rice variety. The local rice grain is short, oblong and thick in size. The grains are usually
difficult to mill (de-husk); the total head rice obtained after milling or de-husking is low. Oryza
glaberrima is hardy; it is resistant to drought, pests and diseases (Linares, 2002) and this explains
the prehistoric evidence of its original cultivation in African countries such as Ghana, Zimbabwe,
Senegal, Mali, Guinea, Liberia, Ivory Coast, Sierra Leone and Nigeria (Djedatin et al., 2011). On
the contrary, it has a low yield and longer growth period. Since Oryza sativa has some desirable
characteristics such as long, thick grain size and higher yield, hybrid varieties have been
developed over the years from these two varieties. NERICA 1 and NERICA 2 are among the
hybrid varieties that have been developed by AfricaRice and which have successfully been
cultivated in Ghana and other African countries (Sie et al., 2012).  About seventy local rice
varieties have been enlisted in a report by Crop Research Institute (2007) with about 29 varieties
cultivated in upland regions and the remaining 41 grown lowland in Ghana. Classification of local
varieties has been poor because of inadequate funds and research leading to a high probability of
same varieties being called differently by farmers who also cultivate these rice grains in different
localities (CRI, 2007).
In Ghana, rice is grown locally by farmers largely in the Northern region as well as the Upper-
East and Volta regions. Even though a significant increased yield potential has been observed
over the years, a report by Ministry of Health (2009-2011) indicated that the local average yield
has been 2.5 tons/hectare/year. This was confirmed by a survey conducted by some rice
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institutions: Crops Research Institute (CRI), Savannah Agricultural Research Institute (SARI),
and International Food Policy Research Institute (IFPRI), where the achievable yield potential
was purged at 6 to 8 tons/hectare after a national average yield of 2.2tons/hectare per season was
recorded. Diako et al. (2010) established that consumers’ preference for imported varieties was
largely related to taste and aroma of the cooked rice in urban areas; thus rice growers have
increased production of locally improved aromatic varieties such as Togo Marshall, Aromatic
Short and Jasmine 85 to compete with those imported (Osei-Asare, 2010). However, the market
value of local rice is still low; mostly utilized by rural dwellers and a few health-conscious people
in urban areas.
Rice is usually consumed mostly as cooked (boiled) rice. According to Gayin et al. (2009), rice is
used in varied forms in Ghana; in pureed form for feeding infants or as breakfast meal, in the
form of balls served with soup and sometimes as milled into flour. Amankwah et al. (2009) in his
study on complementary blends for weaning infants in Ghana reported the addition of rice flour as
one of the starch-based ingredients. Rice has also been applied to complementary foods in the
form of malt (Odumodu, 2007). The rice used in most of these studies is of the variety Oryza
sativa. Ghana produces a higher quantity of local rice as compared to other West African
countries (Assuming-Brempong, 1998). However, poor postharvest handling, lack of storage
facilities, insect infestations, high percentage of brokens, high amount of foreign materials
(stones, weeds, dead body parts of insects) and poor packaging are among the reasons why local
rice varieties are usually branded low grade and undesirable to the Ghanaian consumer.
Processing of cereals has been described as a suitable technique used to transform cereals to
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enable their applications in more acceptable forms(Fernandez-Artigas et al., 2001). Thus, local
rice (Oryza glaberrima) which is nutrient dense (Adu-Kwarteng et al., 2003) could easily be
manipulated to enhance micronutrients bioavailability, flavour and digestibility and used as
complementary food for infants.
2.5 Nutritional Properties of Rice and Its Functionality in Food
2.5.1 Rice Starch
The starch in rice represents the bulk of the nutrients present in the grain.  Its granules are small in
size (between 2-7µm) shaped like a polyhedron (Juliano, 1985; Lii & Chang, 1991; Vandeputte &
Delcour, 2004). Like all starch types, it is made up of amylose and amylopectin. Amylose is made
up of linear α-(1-4) linked glucose units (Vandaputte & Delcour, 2004) while amylopectin is a
branched polymer with α-(1-4) and α-(1-6) glycosidic linkages (Buleon et al., 1998). Rice may be
classified as waxy or non-waxy depending on the ratio of the two starch polymers; amylose and
amylopectin. When the amylose content of rice is higher in comparison to its amylopectin rate, it
is said to be waxy (0-2% amylose) and non-waxy in the contrary (Juliano et al., 1981). The
amylose forms the amorphous portions of starch while amylopectin acts like a crystalline
backbone. The ratio of these polymers contributes to starch functionality in food.
When starch is heated in the presence of excess water, the granules swell, increase in size leading
to the formation of a viscous solution with the simultaneous leaching of amylose; this process is
termed gelatinization (Copeland et al., 2009). A prolonged heating time completely breaks down
the configuration of the granule, improves solubility and an eventual reduction in viscosity is
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observed.  In a recent study comparing pasting properties of local rice with imported rice, Diako
et al. (2010) proposed that flour from local rice could be utilized as food thickeners.  He also
observed higher breakdown viscosity values for local rice and recommended their use in marshy
or pasty foods.  Retrogradation generally occurs after starch cools and forms a crystalline network
from the aggregation of one of glucose polymers due to hydrogen bonding (Hoover, 2001).
Retrograded starch is attributed to amylose or amylopectin; the latter retrogrades at a faster rate
forming double helical linkages involving up to 70 glucose units (Jane & Robyt, 1984).
According to Sievert & Wusch (1993), the linear structure of amylose allows a high tendency of
molecules to realign themselves and recrystallize. Retrogradation due to amylose (Champagne et
al., 1999; Tang & Copeland, 2007) and amylopectin (Lai et al., 2000; Han & Hamaker, 2001) has
been well investigated.
The pasting profile of rice could be measured with a Viscoamylograph or a Rapid Visco-
analyzer. According to Copeland et al. (2009), high peak viscosity values show the susceptibility
of starch to increased water absorption. Rice which is high in amylose content will also record
high values for setback.  Tran et al. (2004) declared a high breakdown value in relation to a better
tasting cooked rice product. The properties of rice starch for most of the imported cultivars of rice
have been well studied (Hsu et al., 2000; Sodhi & Singh, 2003; Noosuk et al., 2005; Singh et al.,
2007).  In the African sub-region, Falade et al. (2014) made a report in literature on the functional
and physiochemical properties of improved varieties of African rice. Lawal et al. (2011) also
isolated rice starches from improved cultivars of rice and characterized them according to their
rheological and functional qualities. The cooking behavior of rice starch is useful for rice-starch
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based applications. Figure 2 gives an illustration of a simple to a simple viscosity-temperature
profile obtained from using Rapid Visco-Analyzer (RVA).
2.5.2 Proteins in rice
Proteins present in rice are a small percentage (Singh et al., 2000); nonetheless they contribute to
the overall nutritional, cooking and eating quality of rice. Like most cereals, rice proteins include
globulin, albumin, prolamin and mostly glutelin (about 80%) (Juliano, 1985; Martin & Fitzgerald,
2002). Comparatively local varieties have higher protein levels per a study conducted by Adu-
Kwarteng et al. (2003) involving ten local rice varieties in Ghana.  Another study carried out in
Nigeria by Osaretin & Abosede (2008) revealed a relatively high protein content (>7 %) in a local
Figure 2a A simple viscosity-temperature profile obtained from using Rapid Visco-
Analyzer. PV: peak viscosity; BD: breakdown viscosity; HPV: hot paste viscosity; SB: set
back viscosity; CPV: cold paste viscosity; CS: consistency (Ibanez et al., 2007)
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variety native to that country known as ‘Ofada’. These rice proteins could individually affect
rheological and physicochemical properties of rice. Baxter et al. (2004) showed that the presence
of prolamin influenced water absorption of rice. It has also been documented that the major
protein in rice, glutelin, and another starch synthase protein (60kDa) have an influence on the
adhesiveness and overall texture of rice starch-based products (Chrastil, 1992; Hamaker &
Griffin, 1993). The total protein content values and the amount of extracted water-soluble proteins
in local rice varieties significantly correlated positively in a report by Adu-Kwarteng et al. (2003).
The variations in rheological behavior of rice attributable to the amount of protein present have
been documented. It was reported that when protein content was low in rice flour it results in an
increase in the peak viscosity (Tan & Corke, 2002). Rice with low protein content is suitable for
cooked rice dishes which require rice grains to be sticky (Okadome, 1999; Lyon et al., 2000).
The protein quality of cereals, in general, is considered poor because of the unavailability of
lysine. Many cereal blends are therefore supplemented with legumes and other protein rich foods
such as milk and fish powder (Amankwah et al., 2009). Fermentation has also been found to be
capable of correcting this deficit in rice (Mugula et al., 2003).  Kabeir et al. (2004) proposed the
addition of skim milk and malting to improve the energy and protein content of ‘medida’
(fermented rice porridge). However, Ramὶrez-Jimếnez et al. (2004) in his study disputed this fact
when he found out that the inclusion of milk in infant cereals caused the absorption of water of
the product which upon storage led to the loss of lysine.  Though previous studies have also
shown the loss of lysine in powdered milk stored at about thirty degrees Celsius (El & Kanvas,
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1997), the key culprit has been an increase in the water activity of the cereal food with or without
milk products (Ramὶrez-Jimếnez et al., 2004).
2.5.2 Other nutrients in rice
The most common minerals in rice that have been investigated are iron and zinc. This is because
their bioavailability has been found to positively correlate with phytate concentration (Graham et
al., 1999). The presence of thiamine, riboflavin and niacin in rice has been scrutinized. A study
carried out on thirty foreign rice varieties developed at International Rice Research Institute
(IRRI) and five pigmented native Philippine rice varieties indicated that pigmented varieties from
Philippine recorded higher values for riboflavin but thiamine levels were similar in all the rice
varieties studied (Villareal&Juliano,1989). Local rice has been found to record relatively high
values for macronutrients. Calcium has been found to be present in some local varieties with
significantly higher concentrations ranging from 20.27 to 26.70 mg/100g (Adu-Kwarteng et al.,
2003). Also, potassium levels in these same local rice varieties studied were relatively high in the
range 80.89–103.88 mg/100 g except for the variety ‘Emo kooko’ which recorded a value of
20.63mg/100g potassium. Phosphorus values were above 100.32mg/100 g (Adu-Kwarteng et al.,
2003).
2.5.3 Starch Digestibility of Rice
Rice starch could be classified according to its resistance to amylolytic enzymes; rapidly/readily
digestible starch, slowly digestible starch and resistant starch (Newton et al., 2011). Resistant
starch is the type of starch that is not broken down by amylolytic enzymes. According to Sasaki et
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al. (2009), rice starches containing a higher amylose ratio are less likely to be hydrolyzed by
enzymes; thus more resistant starch will be formed.  The rapidly or readily digestible starch is
hydrolyzed in twenty minutes; slowly digestible starch is hydrolyzed between 20 and 120 minutes
and resistant starch is not hydrolyzed within 120 minutes. The glycemic index (GI) is a key factor
that determines the starch digestibility of food. According to Roberts & Lui (2009), the glycemic
index is the overall glycemic response following the ingestion of about 50g of carbohydrate when
compared to the value of glucose or white bread. From research, the lower the amylose content,
the higher the glycemic response value (Hu et al., 2004).
Starch digestibility is crucial for infants. A study carried out by Verity & Edwards (1994) found
starch in the faeces of children three years and younger. This could be attributed to the presence
of surpluses of non-digestible carbohydrates (Brown, 1997) in certain cereal based-
complementary foods which cause malabsorption and sometimes diarrhoea in infants (Rowland,
1986). Even though there is documented evidence of benefits relating to the intake of non-
digestible carbohydrate in adults in managing certain diseases (Zhang & Hamaker, 2009); in the
early stages of life, very high or very low levels of non-digestible carbohydrate may influence the
overall well-being of infants over a long period of time (Agett et al.,2003). Rice that is sticky will
have a high glycemic index; local rice with such property when used to produce rice-based
complementary foods would therefore promote digestibility in infants.
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2.5.4 Protein Digestibility of Rice
The quality of protein in cereal depends on its digestibility (Hahn et al., 1982) because it is a
reflection of the amino acid content. When proteins are heated, they denature and are more
susceptible to enzymatic breakdown. Hence food substances that have undergone a high
temperature cooking treatment are more likely to have highly digestible proteins. In vitro
digestibility of proteins could be measured using two key enzymes: pepsin which is involved in
gastric digestion and pancreatin which is involved in duodenal digestion (Petitot et al., 2009). A
study by Petitotet al. (2009) found that increased amounts of wheat proteins in pasta were
digested when pepsin digestion preceded pancreatic digestion in vitro. It has also been reported
that increased protein digestibility have resulted in corresponding increased starch digestibility of
some rice products (Mujoo & Ali, 1998).
2.6 Technologies Used in Processing of Rice Paddy
Rice is harvested as paddy and needs to be processed to obtain the edible grains. Paddy rice is
usually harvested at a moisture content between 12-14%. Raw milling is the processing
technology adopted to remove the husk from the rice grain. Locally, especially in the northern
regions, rice is parboiled before milling because the parboiling treatment decreases the amount
brokenness of the rice after milling (Ayamdoo et al., 2013). His study elaborated the parboiling
methods and advocated for the adoption of the improved parboiling method as the most feasible
and suitable method in the country.
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Parboiling of rice is a common technique widely practiced in Ghana and other parts of the world.
Ayamdoo et al. (2013) explained that parboiling of rice involves three main processes: soaking,
steaming and drying and suggested the improved method of parboiling as ideal and cost effective
(Figure 2b). The soaking time ranges from a few hours to about half a day in order to soften the
paddy, that is, separate the husk from the caryopsis. This is followed by steaming of the paddy to
about 100 ̊C until gelatinization. The steamed paddy is then allowed to cool and sun dried before
milling.  The nutritional benefits of parboiling are that nutrients from the bran are able to
penetrate the endosperm (Kyritsi et al., 2011) and hence, even after milling there is a reduction in
the overall essential nutrients lost. Parboiled rice has a harder texture because it results in the
formation of retrograded starch.
Milling or de-husking of rice involves abrasion to de-hull the paddy rice and to remove the bran
from de-hulled rice to obtain the white polished rice grains (Li, 2004). After milling, the broken
and whole grain kernels are collectively termed as the total head rice produced. Milling of the rice
gives the rice a better storing capability.  Rice with a good milling degree is rice which has as
little remaining bran on the rice grains as possible after milling (IRRI, 2009).
The marketability of rice has a lot to do with the way the paddy was processed. After milling, the
total head rice should fall between 75% and 100%, otherwise, the value of the milled rice grains
depreciates to about half the original price (Trop Rice International Rice Research Institute,
2004). Correa et al. (2007) has argued that attention should be drawn to the operational machinery
used during processing of rice paddy. He continued to explain that unitary operations affect the
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processing of rice paddy rather than the variety. Either way, a large percentage of brokens are still
produced from local rice processing in Ghana.
Paddy rice
Cleaning (washing, removal of debris etc)
Soaking in warm water for 18-24hours
Steaming (vapour heating)
Drying
Water, cooking pots,fire
Water, big containers
Drainage containers, cooking pots, fire
Sunshine, dry wind
Removal of husk mechanically
Milling/De-husking
Package, Ready for sale /Consumption
Sorting/Grading based on Quality
Grading, Packaging
Packaging/Advertising
Figure 2b Improved method of parboiling paddy rice in Ghana (Ayamdoo et al., 2013)
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2.7 Industrial Technologies used in the Food Industry to Produce Ready-to-Eat Cereal
Based Products
The current techniques used in the processing of ready-to-eat food products have emerged to suit
modern day busy lifestyles. Extrusion cooking, flaking, milling, toasting and drum drying are all
processing technologies that transform the appearance, texture and sensory qualities of cereal-
based food products. Traditionally, cereals have been processed using (a combination of) simple
technologies such as soaking, sprouting, milling, boiling, roasting or toasting and fermentation
(Sefah-Dedeet al., 1991; Noutet al., 1993) to produce a variety of ready-to-eat infant food blends,
breakfast cereals and snacks (Afoakwah et al., 2004; Amankwah et al., 2009; Saalia et al., 2012).
Cereals are considered a dominant food group from which infant food production thrives. A
combination of traditional and industrial processes could further improve the application of
cereals.
2.7.1 Traditional Processing of Cereal Food Products
2.7.1.1 Fermentation
Fermentation of cereals is a common practice that has been in existence since the primeval era. In
Ghana, fermented cereals are the main source of the first class of ‘solid foods’ that is given to
infants between the ages six to twenty-four months; a period in the life of the infant when feeding
with only breast milk is insufficient. Fermentation is one of the oldest food technologies which
make use of the biochemical activities of microorganisms converting the organic substrate into
organic acids or alcohols and carbon dioxide (William & Dennis, 2011). Several studies on
fermented weaning blends have focused on maize; where the authors have suggested fortification
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with locally available legumes, tubers and other raw materials (Afoakwah et al., 2004, Amagloh
et al., 2011).  Nonetheless, a few studies carried out in Sudan (Kabeir et al., 2004) and Nigeria
(Boboye & Terwase, 2004) have centered on the use of fermented rice-based products.
Natural fermentation of rice has been proven to involve mainly lactic acid bacteria, yeast and
moulds (Toyada et al., 1979; Uchimura et al., 1991; Sanni et al., 2002). These microorganisms
improve nutritional properties of rice; for instance, protein quality of rice was enhanced by
availability of essential amino acids such as lysine through proteolysis and the presence of debris
of microbial cellular mass (Adams, 1990; Mugula et al., 2003). In a study carried out by Yousif &
ElTinay (2000), natural fermentation of maize dough improved its protein digestibility as well as
soluble protein fractions; albumin and globulin. Similarly, starch digestibility was also improved
by fermentation through the action of amylase enzyme where starch was broken down to glucose
and other sugars (Karovičová, 2007) and was easily assimilated into the blood stream.
The physicochemical properties and the nutritional content of rice-based products are also
influenced by fermentation. According to Lu et al. (2003), fermentation improved the whiteness
of rice flour and decreased its pasting properties such as the gelatinization temperature and the
peak viscosity. The rheological properties of noodles prepared from the fermented rice were also
improved. There has been a report on the mineral content of complementary cereal-based food in
Africa which was enhanced through fermentation (Nicolau et al., 2011) and these findings
encourage a similar application to the local rice processing industry in this country.
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2.7.1.2 Soaking and Malting of Cereals
Soaking of cereals has been found to improve further processing of cereal into other products. It is
a simple treatment that has been used over the years by mothers to prepare baby foods at home.
When cereals are soaked in water, the outer covering absorbs moisture, softens it and leaches out
antinutritional factors. Perlas & Gibson (2002) studied the effect of soaking on the phytic acid
concentration of rice-mug bean-sesame flour and reported an increase in the bioavailability of
iron and zinc in the rice-based complementary food. Soaking followed by decanting reduced the
quantity of phytate in maize flour by about 57% but this also led to a significant loss of
micronutrients (Hotz et al., 2001).
Soaking has been reported to also give some nutritional benefits. When cereals are soaked for a
longer period of time before fermentation or malting, it improves mineral bioavailability (Duhan
et al., 2002). Brown rice was soaked for more than twenty hours before germinating and the
concentration of γ-aminobutyric acid (GABA) was retained even after sterilization (Komatsuzaki
et al., 2007). Chiang & Yeh (2002) established that soaking of rice grains led to a loosening fine
structure and reduced starch damage when that treatment preceded wet milling of rice into flour.
Malting of rice has also been reported as very useful in the production of crude α-amylases to
effect starch hydrolysis (Ayernor & Hammond, 2001) to produce locally fermented cereal-based
products. Recent studies have confirmed successful varied use of malted or germinated cereals in
addition to cereal blends (Kabeir et al., 2004; Saalia et al., 2012). Shelf stable malts are also
commercially available for industrial purposes.
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2.7.2 Industrial Processing of Cereal Food Products
2.7.2.1 Drum Drying
One of the processing technologies applied in the food industry to produce ready-to-eat breakfast
cereals and baby food is drum drying (Valous et al., 2002). Drum drying is a thermal process
which involves the transformation of the main composition of the food product; in this case, the
starch structure, and other functional properties. According to Falagas (1985), the drying process
could be employed to concentrated food products such as fermented rice dough. Two types of
drum-dryers are used in industry; the single and the double drum-dryer with the difference
suggested by their names. Daud & Austrong (1987) have reported in a study that involved the use
of a single drum-dryer to dry rice flour slurry. The double drum-dryer has been also used to dry
fruit purees (Kitson & MacGregor et al., 1982) and sweet corn pulp (Rosenthal & Sgarbieri,
1992). Valous et al. (2002) elaborated the drum-drying technology as one that uses high
temperature from the surface of steam-heated drums to alter the wet food product by completely
gelatinizing and dehydrating the food product to produce drum-dried flakes that are easy to
reconstitute with water. In Ghana, the use of drum drying technology to process cereals for babies
is used in some industries.
2.7.2.1 Extrusion cooking
In extrusion cooking, raw materials are converted into products through a cooking process at high
temperatures for a relatively short time (Zhang et al., 2014). Extrusion allows for a combination
of raw materials and modification of their molecular structures to five a final product with
transformed rheological properties. The twin screw and the single screw extruders are the two
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types available. Extrusion has been widely used for production of breakfast cereals, baby foods
and snacks (Meuser & van Lengerich, 1992).
Rice flour as an ingredient in extrusion has been widely investigated (Ilo et al., 1999; Mouquet et
al., 2003). Ding et al. (2005) studied the effects of feed rate, feed moisture, screw speed, and
temperature on the physicochemical and textural properties of an extruded rice snack product with
a co-rotating twin-screw extruder. Using extrusion cooking, defatted rice bran was added to
develop a ready-to-eat breakfast cereal (Charunuch et al., 2014). Extrusion cooking has also been
continuously proven to be a rewarding processing technology in the food industry.
2.8 Product Development Strategies
It is not unheard of that most of the new food products end their life span in research and
development. This occurs because 33% to 60% of new products are not able to produce the
intended profit margin to sustain the continuous marketing of the products (Schilling & Hill,
1988). In developing a new food product, companies normally used a stepwise approach where
after the ‘new idea’ is identified, a concept is developed, the product is designed followed by the
process before the product is finally commercialized. This process was replaced with the partial
parallel sequence where the process is designed before the product or alongside the  product
formulation to enable manufactures input certain necessary requirements after the product leaves
the ‘laboratory table’ onto pilot scale; since a product’s manufacturing needs may differ at this
point (De Meyer & Hooland, 1990).
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The market for baby food is segmented; purchasing is done according to the availability and
pricing. Thus there is a need to section out product development strategies in order to accomplish
economic gain on local rice-based products. Strategies adopted by industries in the baby food
products sector such as Nestle could be benchmarked to help acquire practical approaches in this
respect.
2.9 Sensory Evaluation of Developed Products
Because the survival of a developed product on the market depends on the consumer, it is very
necessary to ascertain the product’s attributes from the consumer’s point of view. Sensory
evaluation is a scientific technique used to identify different sensory attributes of products which
help to categorize them and asses product acceptability.
An appropriate sensory evaluation method that is advantageous in research in providing a
comprehensive description of sensory attributes of products is the Quantitative Descriptive
Analysis (QDA) (Stone et al., 1974; Stone & Sidel, 2004). The QDA involves the use of a trained
panel who are guided by a panel leader through several sensory training sessions where all
noticeable attributes of products are listed and defined by the panelists without the interference of
the panel leader. The list of descriptors (lexicons) generated in a reproducible manner are then
used by the panelist to evaluate the product with the help of an unstructured line scale which is
used to measure the intensity of each attribute enlisted (Sveinsdóttir et al., 2010) and the intensity
values of the different attributes measured are statistically analyzed with analysis of variance
(ANOVA) and Principal Components Analysis (PCA). The QDA could be described as subjective
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because it depends on the sensitivity of trained panelists and efficiency of training (Dijksterhuis &
Byrne, 2005).
An objective procedure, that is, instrumental electronic sensing method could be used to
determine the descriptive sensory profile (particularly aroma and flavour) of products specifically;
the Electronic nose and Electronic tongue (Figures 3 and 5). These two instruments operate using
electronic sensors. When using the electronic nose (Figure 3) for sensory analysis, the sample is
prepared as would be consumed and placed in covered glass vials with a head space. Sampling is
then carried out by taking an aliquot of the sample headspace, with a syringe, and injecting it into
the detector (Figure 4). Samples with similar odours generally give rise to similar sensor response
patterns while samples with different odours show differences in their patterns. The sensor array
of the electronic nose PEN2 (Figure 3) is composed of 10 Metal Oxide Semiconductor (MOS)
type chemical sensors: W1C (aromatic) W5S (broad range) W3C (aromatic) W6S (hydrogen)
W5C (arom-aliph) W1S (broad-methane) W1W (sulphur-organic) W2S (broad-alcohol) W2W
(sulph-chlor) W3S (methane-aliph). The sensor response is expressed as resistivity ().
The interaction of volatiles with the array of gas sensors incites a series of signals through
interactions between volatiles from the sample or analyte with the array of sensors which are then
interpreted by specialized computer software (Figure 4) such as Minitab v. 18 .  The human
olfactory system has been found to be more sensitive (can detect volatiles at lower parts per
trillion levels with a response time) to a wider range of odours than the electronic nose (Barnett,
1999; Haugen, 2001). Nevertheless, the use of electronic nose in sensory evaluation in recent
times has been found to be very useful in the food industry (Peris & Escuder-Gilabert,
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2009).Electronic tongues are also instruments that mimic taste perception by the human body. It
utilizes electrodes connected to the detector which are immersed into the test sample or analyte
(Figure 5).An electronic tongue is made up of two sensor arrays that are specific for liquid (Figure
5) and are able to evaluate tastes: sourness, saltiness, bitterness umami and astringency. The array
of liquid sensors triggered are then interpreted by a specialized computer software such as
MINITAB v. 18 (Escuder-Gilabert&Peris, 2010).The detecting part of the system consists of 7
sensors whose surface is attached with artificial lipid membranes having different response
properties to chemical substances on the basis of their taste as reported in Table 1.
It was confirmed in a report by Winquist et al. (1998) that the combined use of electronic nose
and electronic tongue for descriptive food sensory analysis provides a more extensive description
of products analyzed. Overall, descriptive sensory analysis provide a widespread depiction of
many food products and can serve as a foundation for differentiating sensory qualities that
significantly reflect consumer acceptability of food products (Stone & Sidel 1993).
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Figure 3 A portable Electronic Nose (PEN 2)
Figure 4 Operational procedure of the PEN 2 electronic nose showing interactions between
array of sensors and volatiles from test sample
2.9.2 1
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Table1 List and characteristics of electronic tongue detecting sensors.
Figure 5A Simple Electronic Tongue (Taste-Sensing System SA 402B)
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CHAPTER THREE
MATERIALS AND METHODS
3.1 Rice Samples
About 75 kg of milled rice and 100kg of paddy rice were procured from a local rice farmer near
Sogakope in the Volta Region of Ghana. The local rice variety used was Togo Marshall
belonging to the locally cultivated rice type Oryza glaberrima. The milled rice was sorted to
remove stones as well as foreign materials and stored in clean airtight large transparent
polyethylene bags at room temperature (about 28˚C)on a wooden pallet and the paddy was
parboiled as described below.
3.2 Parboiling Procedure
This procedure was carried out as described by Ayamdoo et al. (2013). The parboiling process
involved three main operations: soaking, steaming and drying. The rice paddy was first washed
several times until the waste water was clear in colour. The immature seeds that floated during the
washing process were removed using a sieve. The paddy was then soaked in water for about 8
hours and left overnight for 12 hours under standard conditions. Afterwards much of the soak
water was drained off and just enough was left at the base of the pot. The pot was covered tightly
with a lid to prevent the escape of steam during heating. It was then heated for about two hours
and when about a quarter of the rice kernels at the topmost part of the pot began to split, it
indicated the completion of the steaming process and so the heat source was removed. The
steamed paddy was then thinly spread on polythene sheets to dry in a shaded open environment.
The drying process lasted about 3 days (8 hours daily) avoiding direct sunlight. The dried
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parboiled paddy was milled and packaged in clean air tight transparent polyethylene and stored at
room temperature on a wooden pallet.
3.3 Dough Preparation and Fermentation
Twenty kilograms (20kg) of raw milled rice and same amount of parboiled rice were soaked in
excess of de-ionized water (1 part of rice: 2 parts of water) at room temperature (about 28˚C) for
12 hours. Then the steep water was drained off and the rice grains washed twice with de-ionized
water and drained.  The wet rice grains were then milled into rice grist using a disc attriution mill.
The mean moisture content attained for the rice grist was about 36% and 45% for milled and
parboiled rice respectively. Enough de-ionized water was added to prepare rice dough of 45% and
55% for the raw milled and parboiled rice respectively. About 5g of a starch hydrolyzing enzyme
(alpha-amylase) was then mixed with the rice dough. The dough was then allowed to undergo
spontaneous fermentation for 0, 12, 24 and 48 hours at room temperature (28˚C). At the end of
each fermentation time, rice dough samples of both milled and parboiled rice were packaged in
clean transparent stomaca bags and stored in a freezer at -20 ˚C. Figure 6 is a flow chart showing
the production procedure of the drum-dried fermented rice-based ready-to-eat products.
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3.4 Drum-Drying Process
The double drum dryer was used in this experiment as described by Valous et al. (2002). The
counter rotating drums were heated with steam at 45psi and rotated at 5rpm. The dough samples
were fed unto the rotating drums to form a thin paste on them. The dried flakes obtained as the
drums turned were collected and further dried in an air oven preset at 50 ˚C for about an hour and
half to ensure a well dried product. The oven-dried drum-dried flakes were then milled into a dry
Rice Sort Soak (12 hours)
Drum-dry
Wash
Rice Dough Preparation (45&55% moisture content)
Fermentation (0, 12, 24, 48 hours)
Packaged fermented rice cereal
Mill (Dry)
Oven dry (50 degrees Celsius)
Mill (wet)
Water Amylase
Enzyme
Figure 6 A flow chart showing the preparation of fermented rice-based baby food
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powdered final product using a hammer mill (Size 8 laboratory mill, Christy and Norris Ltd,
Chelmsford, England) equipped with sieve size 4mm. The final product were then packaged into
air-tight transparent plastic bags and sealed.
3.5 Analytical Procedures
All chemicals used were of analytical grade and obtained from Sigma-Aldrich, St Louis, USA.
3.6 Proximate analysis
3.6.1 Moisture content
Moisture content was determined on the raw rice samples, soaked rice samples, milled dough
grist and drum dried products for both milled and parboiled rice. Moisture analysis was performed
according to the AOAC Official Standard Method (AOAC, 2000). Measurements were done in
duplicates.
3.6.2 Water activity
Water activity values were determined using a Rotronic Hygrometer (Model DT) at 25 ˚C
according to Reh et al. (2004). Instrument was calibrated before use with reference standards.
Measurements were carried out in duplicates.
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3.6.3 Protein Solubility and Gel Electrophoresis Pattern
With the characterization of the proteins present in the baby food samples, the amount of protein
dissolved was determined in native and denaturing conditions using the Bradford method
(Bradford, 1976)while the gel electrophoretic pattern of proteins was determined using SDS-
PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis).
3.6.3.1 Protein Solubility
This experiment involved three extraction buffers: Buffer A (Saline Buffer); NaCl (100mM) +
NaH2PO4.2H2O(50mM), Buffer B (Saline-Urea Buffer); NaCl (100mM) +
NaH2PO4.2H2O(50mM) + Urea (6M) and Buffer C (Saline-Urea-DTT Buffer); NaCl (100mM)
+ NaH2PO4.2H2O(50mM) + Urea (6M) +  dithrethiol (10mM).The proteins were extracted by
vortexing a solution of about 4ml of each buffer added to each of three samples weighed in
duplicates at about 0.120g. The resulting sample solutions were then stirred on a shaker for an
hour, then centrifuged at 3000*g for 30 minutes at room temperature. The supernatant was then
collected for both Bradford and SGS-PAGE analysis. The Bradford procedure was used to
determine protein concentrations by diluting the extract or supernatant with Buffer A (Iametti et
al., 2006) using spectrophotometric procedure with wavelength (λ) set at 595nm (Bradford et al.,
1976). Soluble protein content of the supernatant was calculated as mg soluble protein /g baby
food sample.
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3.6.3.2 Sodium Dodecyl Sulphate-Poly Acrylamide Gel Electrophoresis Pattern (SDS-
PAGE) of extracted proteins
Sodium Dodecyl Sulphate-Poly Acrylamide Gel Electrophoresis Pattern (SDS-PAGE) was
carried out according to Iametti et al. (2006). The supernatant collected during the previous step
was diluted with 1/1 (v/v) concentrated SDS-PAGE denaturing buffer (0.125 M Tris-HCl, pH 6.8;
50% w/v glycerol, 1.7% w/v SDS; 0.01% w/v Bromophenol Blue) containing 1% β-
mercaptoethanol (v/v). The protein denaturing process took place after heating to 100 ᵒC for five
minutes. The electrophoresis was performed on a stationary porosity gel (12% monomer, XT Mes
20x, BioRad, Richmond,VA, USA), first at constant of 10 mV per gel for thirty minutes followed
by a final increase to 16mV per gel for about two hours. For clearer viewing and identification of
bands, all gels were stained overnight with Coomassie Brilliant Blue R250 (Simply Blue
Safestain, Invitrogen, Carlsbad, CA, USA) with molecular weight markers ranging from 96 to 14
kDa (BioRad and Novex, Richmond, VA). The gel was then destained by washing several times
with a destaining solution) until bands were clear on viewing. The gels were scanned using
ScanMaker 4 (Microtek, Carson, CA, USA) at a resolution of 1000 dots per inch.
3.7 In vitro Protein Digestibility
Protein digestibility was carried out by a two-step proteolysis using pepsin followed by pancreatin
as described by Petitot et al. (2009) with slight modifications. In vitro protein digestibility tests
were carried out by using pepsin and pancreatin. For the in vitro pepsin digestion, 1.0g of finely
ground sample was weighed into polypropylene test tube. About 10 ml of HCl 0.05 M was then
added. Proteins were hydrolyzed by gastric pepsin (porcine stomach mucosa, EC 232-629-3, ref
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P7012, Sigma) by adding 30µl of pepsin at a concentration of 2mg/ml. The mixture was then
incubated for 60 minutes at 37 °C under mixing conditions. In vitro pepsin digestion was
terminated by the addition of 10% (final concentration) trichloroacetic acid. Samples were then
centrifuged at 13000 x g for 15 min, and the hydrolyzed peptide content in the supernatant was
measured at 280 nm. After pepsin treatment, sample pH was adjusted to 8.0 with TRIS 1 M, and
0.12 ml (5mg/ml in sodium phosphate buffer) pancreatin from porcine pancreas (EC 232-468-9,
ref P1625, Sigma) was added. Pancreatin digestion was stopped by the addition of 10% (final
concentration) trichloroacetic acid after 60, 120, and 180 min. Samples were then centrifuged at
13000 x g for 15 min and the hydrolyzed peptide content in the supernatant was measured at 280
nm.
3.8 Colour Determination
The colour of fermented rice-based baby food samples were measured using a colorimeter
(Model:Minolta CR-300, Japan) where L* is lightness value, a* is redness/greenness value and b*
is yellowness/blueness value. The L value gives a measure of the lightness of the product colour
from 100 representing pure white to zero representing black, as would be assessed by the human
eye. A standard white calibration plate was used to calibrate the instrument. Five replicates were
obtained for each sample and the averages were calculated: Y=94.55; x= .3131 y= .3195. The
total colour difference ‘∆E’ was also calculated as follows:
∆E= √(∆L*)2 + (∆a*)2 + (∆b*)2
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3.9 Pasting Properties
The Micro-Visco Amylograph, (MVA) (Brabender OHG, Duisburg, Germany) was used in the
determination of the pasting characteristics of the fermented rice-based baby food samples
according to Mariotti et al. (2011). The moisture content of the samples was corrected to 14% and
then a slurry was prepared with approximately 11.0g to about 100ml of deionized water.  The
slurry was first heated to 30°C where the temperature was held for 5 minutes then further
increased to 95°C, held for 30 min at that temperature then dropped back to cool at 30°C while
holding for another 5 minutes.  The parameters determined included the gelatinization
temperature; peak viscosity; breakdown; final viscosity and the setback.
3.10 Thiol determination
3.10.1 Accessible Thiols
In this experiment, about 0.150g of samples were measured into sample tubes in pairs as
described by Iametti et al. (2006) and then about 5ml of Buffer A (NaCl (100mM) +
NaH2PO4.2H2O(50mM)) was added. Except for the blank, according to Ellman (1959), about
0.2mM 5,5’-dithiobis-(2-nitrobenzoic acid) (DTNB) was added to each buffer before adding to
the samples. The resulting solutions were then stirred for an hour at room temperature. They were
then subjected to centrifugation at 3000*g for half an hour and the absorbance of the supernatant
of each sample was measured at a wavelength of 412nm. The results obtained were expressed as
mmol accessible thiols/g protein after deductions from total thiols results.
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3.10.2 Total Thiols
Here, also about 0.150g of samples were measured into sample tubes in pairs and then about 5ml
of Buffer B (NaCl (100mM) + NaH2PO4.2H2O(50mM) + Urea (6M)) containing 0.2mM 5,50-
dithiobis-(2-nitrobenzoate) (DTNB) was added. For the blank, no DTNB was added to the buffer
before adding to the sample. The following steps are similar to the accessible thiols
measurements. However, the results obtained were expressed as mmol total thiols/g protein.
3.11 Water Absorption Capacity and Water Solubility Index
Water absorption capacity index (WAI) and water solubility index (WSI) was carried out
according to Anderson et al. (1969). About 2.5 g of each sample was suspended in 25 ml of
deionized water at 30 ˚Cin a previously weighed 50 ml centrifuge tube, stirred
vigorously for 30 minutes and then centrifuged at 3000 g for 10 min. Afterwards, the residue  was
weighed and the Water Absorption capacity was calculated as follows:
WAI (% d.b.) = (weight of sediments /weight of dry solids) χ 100.
The supernatant of each sample was then weighed into a tarred evaporating dish. This was then
evaporated until gel formation and oven dried at 130 ˚C for 16 hours. The water soluble index
was thus calculated as:
WSI (% d.b.) = (weight of solublesolidsin supernatant/weight of dry solids) χ 100.
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3.12 pH and Titratable Acidity
The pH and titratable acidity values were measured using samples suspensions of the fermented
dough and the final product, according to Lonner & Preve-Akesson (1988) with slight
modifications. About 10 g of each sample was weighed (n=3) and 100 ml of distilled water was
added to each sample. The resulting suspensions were stirred using a magnetic stirrer for 30
minutes. After centrifuging at 5000* g for 20 minutes at 18 ˚C, 40 ml of the supernatant was used
in the assay. The pH of the supernatant of each sample was then measured by a previously
calibrated Crison GPL 22 pH meter.
The titratable acidity was determined by titrating 40 ml of supernatant with 0.5M NaOH until a
pH of 8.5 was reached. Values obtained were expressed as the ml of 0.1M NaOH needed to titrate
10g of products.
3.13 Starch Digestibility
Starch digestibility was estimated according to Englyst et al. (1992) by determining the glycaemic
index, digestible starch (rapidly or readily digestible starch and slowly digestible starch) and free
sugars content.
Free glucose was measured by dissolving about 1g of each sample in 2M KOH and bringing to
boil at 100 ˚C for 30 min. The solution was then subjected to invertase action (0.2 ml, Boehringer
Mannheim) at 37˚Cfor 30 minutes. This was vortexed; 0.5ml was transferred into 10ml of ethanol
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and centrifuged. Glucose content of the supernatant was measured using the glucose oxidase-
peroxidase kit (Boehringer, Cat Number 166391).
To evaluate the total starch, about 1g of each sample was placed in 50ml centrifuge tubes and an
internal standard (5ml arabinose) was added. This was then subjected to pepsin treatment at 37 ᵒC
for 30min. Sodium acetate and an enzyme mixture (pancreatin, amyloglucosidase, invertase) was
added with glass beads and placed in a shaking incubator at 37 ˚C.  At the 20 and 120 min after
hydrolysis was initiated, aliquots of samples were taken from the incubation mixture, centrifuged
and 70 µl of supernatant was transferred into vials containing 1ml of water. The glucose released
at 20 and 120 min was measured as rapidly available glucose or starch (RAG) and slowly
available glucose or starch (SAG) respectively. The remainder sample solution was vortex-mixed
and heated to 100 ˚C for 30 min, then cooled to 0 ˚C. 10ml of 7M KOH was then added, vortex-
mixed again and placed in a shaking incubator at 0 ˚C for 30 min and vortex-mixed. An aliquot of
0.2 ml was transferred into I ml of 1M acetic acid and 40 µl of amyloglucosidase was added. This
was then warmed to 70 ˚C for 30 min and heated to 100 ˚C for another 10 min. Then 12ml of
ethanol was added and the resulting solution was centrifuged. About 200 µl of each sample
supernatant was transferred into vials containing 1ml of deionized water and vortexed. The total
glucose released was then measured by high-performance liquid chromatography (HPLC).
The resistant starch is calculated as the difference between total glucose (TS) and slowly available
glucose (SAG). Digestible starch was also calculated as the difference between total starch and
resistance starch.
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3.14 Sensory Evaluation of Fermented Rice-Based Products
Sensory evaluation of samples was carried out subjectively using quantitative descriptive analysis
(QDA) while the electronic nose and electronic tongue gave objective results. For the QDA, eight
panelists made up of graduates and post-graduates from the Nutrition and Food Science
Department, University of Ghana were used. Electronic nose was used to evaluate the aroma of
the final products, while electronic tongue gave the flavour attributes of products.
3.14.1 Electronic Nose Measurements
The electronic nose is an innovative technological procedure that was developed in order to
imitate the way the olfactory system of humans operate (Balwin et al., 2011) with the
odour/flavor perceived as a global fingerprint. A Portable Electronic Nose (PEN2) from Win
Muster Airsense (WMA) Analytics Inc. (Schwerin, Germany) was used in this experiment. The
electronic nose had essentially a sample delivery section where the volatiles that were collected in
the headspace were injected into the detection system which contained the sensors (in this case, a
metal oxide semiconductor) and the array of signals was interpreted on the computer with
installed software.
About 0.5g of lyophilized samples was dissolved with 500 µL of water and placed in a 40 mL
airtight glass vial fitted with a pierceable Silicon/Teflon disk in the cap. After a 1 hour headspace
equilibration at room temperature to stabilize the odours in the food sample and allow the
volatiles to be collected in the headspace, the measurement process was carried out. Samples were
evaluated in duplicates. The conditions of operation were: flow rate 300mL/min, injection time 60
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min, flush time 180 min, during which the surface of the sensors was cleaned with air filtered
through active carbon. Sensor responses were recorded for all samples and subsequently
multivariate analysis was used to determine the difference between samples statistically.
3.14.2 Electronic Tongue Measurements
Instrumental (objective) sensory analysis was executed using the Electronic Tongue (ET), a taste-
sensing System SA 402B (Intelligent Sensor Technology Co. Ltd, Japan). About 15g each of
lyophilized samples was weighed into falcon tubes containing 200 mL of deionized water.
Solutions were vortexed for about 5 min and centrifuged at 5000*g for 10 min at 20°C. After
centrifugation, the supernatants were filtered and analyzed in triplicate. For the preparation of the
taste sensors,a total of 5 detecting sensors and 2 reference electrodes were used, separated in two
arrays according to membrane charge: hybrid (CT0; CA0;AAE) and positive (C00, AE1). The
detecting sensors and reference electrodes were first dipped into the reference solution (30 mM
potassium chloride and 0.3mM tartaric acid) and the electric potential measured for each sensor
was defined as Vr. Then the sensors were dipped for 30 seconds into the sample solution. For
each sensor the measured potential was defined as Vs. For each sensor the “relative value” (Rv)
was represented by the difference (Vs-Vr) between the potential of the sample and the reference
solution. Sensors were rinsed with fresh reference solution for 6 seconds and then dipped into the
reference solution again. The new potential of the reference solution was defined as Vr’. For each
sensor, the difference (Vr’-Vr) between the potential of the reference solution before and after
sample measurement was the CPA value (Change of Membrane Potential caused by Absorption)
(CPAv) and corresponded to the “aftertastes” of the electronic tongue device. Before each new
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measurement cycle started, electrodes were rinsed for 90 s with a washing solution and then for
180 seconds with the reference solution.
Each sample was evaluated in duplicate and the means of the sensor outputs were converted to
taste information. The “taste values” were calculated by multiplying sensor outputs for
appropriate coefficients based on Weber–Fechner law, which gives the intensity of sensation
considering the sensor properties for tastes. Specifically, the “taste values” were estimated as:
Sourness = 0.3316 × Rv(CA0)
Saltiness = −0.252 × Rv(CT0)
Bitterness = −0.140 × Rv(C00) + 0.084 × Rv(CT0)
Aftertaste-bitterness = −0.210 × CPAv(C00)
Astringency = 0.1575 × Rv(AE1) + 0.1575 × Rv(CT0)
Aftertaste-astringency = −0.252 × CPAv(AE1)
Umami = -0.1575 ×Rv(AAE)
Richness = -0.420 × CPAv(AAE)
3.14.3 Quantitative Descriptive Analysis (QDA)
The Quantitative Descriptive Analysis (QDA) was used to assess the fermented rice-based baby
food products according to Stone & Sidel (2004). A descriptive trained panel (n=8) developed
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lexicons that defined each of the eight fermented rice-based baby food samples (milled and
parboiled rice fermented at times 0hr, 12hr, 24hr, 48hr) in duplicate using a 15-cm line scale.
Inherent product attributes such as appearance, aroma, flavor, texture (Moscowitz, 1995) and
after-taste were scrutinized and a final list of lexicons were developed by the descriptive panel
with the guidance of the panel leader as a facilitator after seven sessions (two screening sessions
and five training sessions) that lasted about two and a half hours per session.
3.14.3.1 Panel Selection and Training
Twenty panelists were recruited from Nutrition and Food Science Department, University of
Ghana. Selection was based on interest to participate, good health conditions, time availability
and absence of food allergies. Panelists were prescreened on their ability to distinguish basic
tastes in solution, detect basic aromas and flavours and also describe basic attributes associated
with fermented and baby food products.
Training sessions began with a brief insight into descriptive sensory analysis of food products.
Each sensory session lasted up to two and half hours. During this period, panelists were presented
with four products which they were required to evaluate individually. Each session was concluded
with discussions among panelists where a common list of descriptors and their respective
definitions were developed for each attribute. Panelists were also introduced to diverse reference
samples that enabled the elimination of redundant descriptors until a final list of clearly defined
descriptive terms was drawn up and their intensities rated on a 15cm scale after five training
sessions.
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3.14.3.2 Product Evaluation
Products were presented in no particular order to the eight panelists in individual booths in a clean
well lit sensory laboratory. The panelists evaluated the products in two forms: the powdered form
and then in a reconstituted form (as would be consumed by baby) in 1 part of product: 5 parts of
water. Samples were presented in 30ml small plastic cups placed in a white tray and each one of
the trained panelists performed the evaluation using the developed list of descriptors and their
definitions for each sample. The evaluation sessions were repeated twice to increase precision.
Panelists were made to rinse their palettes with clean water and unsalted crackers between
samples during taste sessions. Intensities of each of the attributes were rated on the 15-cm scale,
where ‘none’indicated the nonexistence of intensity, and fifteen tallied the most ‘extreme’
intensity. References were included where necessary.
3.15 Statistical Analysis
All data were analyzed using MINITAB V. 17. Two-way analysis of variance (ANOVA) was
performed using the General Linear Model (GLM) test and Tukey’s test was used to compare the
differences between sample means. Statistical differences were observed as significant at p-value
≤ 0.05.Microsoft Excel was used to plot column and line radial graphs. Quantitative descriptive
analysis results of sensory attributes were elaborated with radial graphs also plotted using
Microsoft Excel. The Principal Component Analysis (PCA) was performed with correlation
matrix on the means of all the sensory data to obtain the main variation in the descriptive sensory
profiles of aroma and flavour attributes and represented in scores and loadings plots.
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Pearson correlation analysis was performed betweencertain parameters and selected sensory
attributes such as colour, aroma and flavour; total colour difference (∆E), L*; a*; b*;pH and
titratable or total acidity respectively. All treatments and analyses were conducted in duplicates
and the mean values and standard deviations were stated.
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CHAPTER FOUR
RESULTS AND DISCUSSION
4.1 Physicochemical Properties of the Drum-dried Fermented Baby Food
4.1.1 Colour
Colour is an important measure of quality in product development because it plays a crucial role
in consumer acceptability. Colour measurements were expressed as CIE L*, a*,b*measurement,
where L*, a* and b* represented the lightness (against a white tile scale of 100 and a black tile
scale of 0), redness (+)/greenness(-) and yellowness (+)/blueness (-)values respectively.  The L*
values of both milled and parboiled rice tended to increase with fermentation time indicating that
they became lighter in colour (Table 2). The effects of fermentation time and rice treatment
showed significant interactions (p=0.00). Even though Onyango et al. (2004) made a contrasting
observation where fermentation decreased the lightness value, this study agreed well with Lu et
al. (2005) who reported that fermentation improved the whiteness index of rice-based flours
which could be attributed to starch purification during fermentation.
As expected, overall, low redness values (a* values) were recorded for all the fermented rice-
based baby food products (Table 2). Parboiled samples declined in redness values as fermentation
time increased. Fermentation time and rice treatment interactions were significant (p≤0.05).
The b* values obtained indicated yellowness in samples (Table 2).There were significant
interactions observed with respect to fermentation times and rice treatment type. It was found that
there was a gradual increase in yellowness with fermentation time in milled rice samples from
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18.90 to 22.87; however a drip to 17.36 was observed after 48 hours of fermentation (Table 2). In
contrast, parboiled rice products recorded a decrease from 17.63 to 15.41(Table 2). The
differences observed may be due to the presence of available sugars in the milled rice until a
period of 48 hours of fermentation by which time most of the sugars were converted into acids
indicating effect of acidic environment on colour. A p-value of 0.00 (p≤0.05) showed that all
values recorded for the L*, a*, b* were significantly different with respect to fermentation time
and treatment.
The negative ∆L* values obtained for all samples (Table 2) except these: 24-hour fermented
parboiled product (∆L* =1.52) and 48-hour fermented parboiled product (∆L* =2.10), showed
that milled samples were darker than parboiled samples as compared to control samples (raw
milled and parboiled rice grains). It was also observed that as fermentation time increased,
samples became lighter in colour as compared to raw rice. Positive ∆a*values (Table 2) indicated
more redness in all samples comparative to raw milled and parboiled rice respectively which
could be attributed to fermentation since treatment effects were not significant in this case
(p≥0.05) .  These values declined with increasing fermentation times except for an observed
discrepancy shown in the 24-hour milled product (1.95).  Values for ∆b* were positive, an
indication of observed yellowness in all samples relative to raw rice samples (Table 2b). The ∆b*
values decreased with increasing fermentation time in parboiled samples while in milled samples
there was an increasing trend until the 48-hour fermentation time recorded a fall in value (9.85).
This could be ascribed to the presence of increasing available sugars in milled samples until at 48-
hour fermentation time when these sugars were converted to acids.
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Delta E (∆E) is the total colour difference taking into consideration the three tristimulus
difference of ∆L*, ∆ a* and ∆b*. The higher the delta E, the greater the colour difference between
the product and the raw material. Lower delta E values recorded by parboiled products showed
they were similar to the colour of their raw material (lighter) as compared with milled samples.
Fermentation time interactions with regard to treatment significantly contributed to the decline in
obtaining darker products correspondingly. Discrepancies observed in these samples: the 24-hour
fermented milled product (∆E=16.51) and the 24-hour parboiled product (∆E=2.35) may have
been caused by processing factors.
Rice Type Fermentation
time/hr
L* a* b*
Milled 0 83.80±0.53a 1.61±0.08c 18.90±0.18d
12 86.06±0.24b 1.29±0.13b 19.77±0.32d
24 86.40±0.29b 1.99±0.28d 22.87±0.69e
48 86.62±0 .42c 0.39±0.17a 17.36±0.92a
Raw rice (milled) - 92.15±0.26e 0.04±0.03a 7.51±0.15f
Parboiled 0 83.48±0.24a 1.73±0.15d 17.63±0.19a
12 83.68±0.41a 1.63±0.08c 16.55±0.39a
24 86.73±0.36c 1.24±0.10b 15.54±0.41a
48 87.31±0.51d 1.21±0.05b 15.41±0.24a
Raw rice (parboiled) - 85.21±1.39b 0.29±0.07a 14.01±0.45a
Table 2a Estimated means ± standard deviations of the tristimulus colour values. p-value≤0.05
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4.1.2 pH and Total (or Titratable) Acidity
pH is the logarithmic measure of the concentration of hydrogen (H+) ions in aqueous solution.
Titratable acidity measurements are usually coupled with pH measurements because the former is
a better measure of acidity since it gives the total acidity of the products by measuring acidy due
to concentration of free H+ ions as well as the H+ions bound to the weak or organic acid (in this
case, lactic acid). Overall, while the pH decreased, both milled and parboiled samples displayed
an escalating pattern in total titratable acidity values in reference to increasing fermentation times
showing an inverse relationship between the two parameters. Figure 7 shows the inverse
relationship between pH values and titratable acidity measured as percent lactic acid in the baby
food products. Parboiled products recorded lower pH values and corresponding higher titratable
Table 2b Estimated means ± standard deviations of the tristimulus and total colour difference. p-value≤0.05
Rice
Type
Fermentation
time/hr
∆L* ∆a* ∆b* ∆E
Milled 0 -8.35±0.71a 1.57±0.11a 11.39±0.21f 14.21±0.75 d
12 -6.09±1.43a 1.25±0.15a 12.26±0.45g 13.75±1.50b
24 -5.75±0.29a 1.95±0.28a 15.36±0.69h 16.51±0.80e
48 -5.53±0.42a 0.35±0.17a 9.85±0.92e 11.31±1.03a
Parboiled
0 -1.73±1.29d 1.44±0.19a 3.62±0.35a 4.27±1.35b,c
12 -1.53±0.41d 1.34±0.08a 2.54±0.39 a 3.26±0.57b,c
24 1.52±0.36e 0.95±0.10a 1.53±0.41 a 2.35±0.55a
48 2.10±0.51 f 0.92±0.051a 1.40±0.24 a 2.69±0.57a
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acidity values in all samples as fermentation times increased with the highest value of
(0.150±0.003) % lactic acid in the 48-hour fermented baby food product. This is because
gelatinized starch products are more susceptible to fermentation than non-gelatinized starch
products (Singh & Soni, 2001).The drop in pH values as fermentation time increased was more
gradual with the milled product than with the parboiled fermented products (Figure 7). In general,
decreased pH values and corresponding acidity increases observed is a common property for most
fermented products (Blandino et al., 2003). This impedes the growth of food-related pathogens in
fermented products and thus renders them safe (Blandino et al., 2003).
Figure 4.1.2 1
figure 4.2.1 1
Figure 4.2.1 2
3
3.2
3.4
3.6
3.8
4
4.2
4.4
0.001
0.021
0.041
0.061
0.081
0.101
0.121
0.141
0.161
0.181
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Fermentation time/hr
pH
TA
 
(%
 
la
ct
ic
 
a
ci
d)
TA (milled rice) TA (parboiled rice)
   pH (milled rice) pH  (parboiled rice)
0hr 12hr                    24hr 48hr
Figure 7 pH and titratable acidity (%TA as lactic acid) of milled and parboiled fermented rice-
based baby food products as a function of fermentation (p≤0.05).
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4.1.3 Proximate composition comparing physico-chemical properties of dough with final
products
The pH and total titratable acidity of the baby food products significantly varied between
treatments and fermentation times for both fermented dough and final products (p≤ 0.05) (Table
3). As expected, pH values showed a decreasing trend with increasing fermentation times in all
samples (both dough preparations and final products) due to the formation of organic acids during
fermentation (Blandino et al. 2003). From Table 3, dough samples showed lower pH values with
corresponding higher total acidity values. Variations in pH and TA values for dough and final
product when compared showed significant difference respectively (p≤0.05).
Moisture content of dough samples ranged from 41.15 to 42.49% for milled rice and 51.33 to
57.55% for parboiled rice (Table 3). These results are ascribable to the different amounts of water
added during dough preparation to the rice grists of the two products; milled and parboiled rice.
The drum-drying cooking process significantly (p-value=0.00) reduced the moisture content to
(5.88 – 7.84) % and (5.12-11.22) % for milled and parboiled rice respectively (Table 3).
Generally, milled rice had lower moisture content than parboiled rice (Table 3). As fermentation
increased, the moisture content decreased for parboiled samples; however a vice versa situation
occurred for the milled samples, but then differences between the final products for both milled
and parboiled samples were statistically insignificant (p≥0.05).When the moisture content values
of dough and final products were compared, significant differences were observed for both milled
and parboiled rice (p≤0.05).
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Water activity and moisture content are important preservation indices of dehydrated food
products (Al-Muhtaseb et al., 2002). When these two parameters are controlled, they could affect
the storage stability of food products. From figures 8a and 8b, it was observed that as
fermentation increased, moisture content increased while water activity increased slightly in
milled samples. Parboiled samples, however, showed a decreasing trend in moisture content and
water activity as fermentation proceeded. Parboiled samples had an initial higher value of water
activity which drastically reduced with increasing fermentation time. The trend observed in
parboiled samples confirms that as fermentation proceeded sugars were constantly used up by
microorganisms. The increases in moisture content and water activity recorded by milled samples
showed that glucose concentrations in these samples were higher at 12-hour fermentation in
milled rice-based samples (Figures 8a and 8b). As water activity increased, glucose in the food
products tended to absorb water from the atmosphere with the application of high temperatures
which led to an increase in moisture content (Kapsalis, 1987). Fermentation time and treatment
interactions on moisture content were not significant. Conversely, fermentation significantly
influenced water activity of the fermented milled and parboiled rice-based baby food products
(p≤0.05).
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Rice Treatment Milled Rice
Fermentation time 0hr 12hr 24hr 48hr
pH Dough 3.85±0.01d 3.66±0.01c 3.52±0.00b 3.42±0.01a
Final Product 4.02±0.01d 3.76±0.02b 3.66±0.04c 3.54.±0.04a
TA
(%lactic acid)
Dough 0.060±0.005a 0.084±0.005a 0.093±0.005a 0.123±0.010b
Final Product 0.032±0.01a 0.048±0.040a 0.088±0.001b 0.128±0.001c
Moisture
Content (%)
Dough 42.49±0.01a 41.65±0.01a 41.90±0.21a 41.15±0.74a
Final Product 5.88±1.08a 6.71±0.56a 7.84±0.15a 7.12±0.26a
Rice Treatment Parboiled Rice
Fermentation time 0hr 12hr 24hr 48hr
pH Dough 3.88±0.01d 3.62±0.01c 3.49±0.00a 3.41±0.01a
Final Product 4.13±0.01d 3.58±0.02a 3.64±0.04b, c 3.38±0.04a
TA
(%lactic acid)
Dough 0.135±0.001b 0.168±0.005d 0.198±0.009d 0.228±0.005e
Final Product 0.046±0.001a 0.114±0.001c 0.102±0.002c 0.150±0.003d
Moisture
Content (%)
Dough 57.55±0.08 53.05±2.79 51.33±1.66 54.34±1.28
Final Product 11.22±0.25a 8.72±0.59a 5.12±0.15a 5.22±0.16a
Table 3 Proximate composition table comparing fermented dough and final baby food products
from milled and parboiled rice.
*Values followed by same lower-case letters in the same row are not significantly different (p≥0.05).
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Figure 4.3.1 1
5.88
6.71
7.84
7.11
0.34
0.53
0.40
0.48
0.00
0.20
0.40
0.60
0.80
0.00
2.00
4.00
6.00
8.00
10.00
0hr 12hr 24hr 48hr
M
o
ist
u
re
 
co
n
te
n
t %
Fermentation time (hour)
Milled
M/C
aw
a
w
11.22
8.72
5.11
5.22
0.65
0.65
0.37
0.30
0.00
0.20
0.40
0.60
0.80
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0hr 12hr 24hr 48hr
M
o
ist
u
re
 
co
n
te
n
t %
Fermentation time (hour)
Parboiled
M/C
aw
a
w
Figure 8a Moisture content and water activity of milled fermented rice-based baby food products
as a function of fermentation (p≤0.05).
Figure 8b Moisture content and water activity of parboiled fermented rice-based baby food products
as a function of fermentation (p≤0.05).
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4.2 Functional Properties of Baby Food Products
4.2.1 Hydration properties:
4.2.1.1 Water Absorption Index (WAI)
A fundamental property of pre-cooked ready-to-eat foods is their rehydration characteristics. Pre-
cooked and baby food cereals should have excellent rehydration properties in which large
volumes of water are absorbed. There were significant differences observed between values for
water absorption index in all fermented parboiled and milled samples. Higher WAI values were
obtained for milled samples (Figure 9a) as fermentation time progressed from the 12 hour
fermentation period through to the 48th hour. On the other hand, parboiled samples which
recorded lower absorption values showed only a slight decrease in values with respect to an
increasing fermentation period (Figure 9a). Treatment and fermentation interaction was
significant among products (p≤0.05). Parboiling treatment caused significant differences among
samples while fermentation time was statistically insignificant (p≥0.05).Water absorption index is
a measure of the amount of water available for swelling, followed by gelatinization; often related
to the behavior of starch granules in the presence of water (Elkhalifa et al., 2006). The lower WAI
values recorded for parboiled samples were probably due to the incidence of degraded starch
granules which restricted the swelling power of the starch resulting in a decreased capacity for
water absorption. The period of fermentation from the 12th hour contributed to a lower resistance
to swelling as observed in milled samples (Figure 9a) due to the presence of excess available
starch. This suggests that fermented parboiled samples will yield thinner gruels; this is similar to
results reported by Elkhalifa et al. (2006) in a study based on effect of fermentation on the
functional properties of sorghum flour. It is possible that the reduction in the WAI values during
fermentation of parboiled samples was as a result of the presence of greater amounts of broken
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down starch granules which further reduced the swelling capacity. Parboiling and the subsequent
drum drying process contributed to the breakdown of starch molecules. This agrees with a study
by Onyango et al. (2004) where decreasing WAI values were obtained for extruded fermented
maize–finger millet blends used in the production of ‘uji’.
Figure 4.2.1.1 1
A0 A1 A2 A3 N.a.N. B0 B1 B2 B3
WA
I
0
4
8
a
b b
b
b
a
a
a
Figure 9a Effect of fermentation time and parboiling treatment on water absorption index (WAI). A:
milled rice; B: parboiled rice. Similar lower-case letters shows differences are insignificant (p≥0.05).
0-zero hour fermentation
1-12 hour fermentation
2-24 hour fermentation
3-48 hour fermentation
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4.2.1.2    Water Solubility Index (WSI)
Water solubility is a measure of the degree of solubility when higher-molecular starch materials
are broken down to lower polysaccharide units. Usually, solubility increases after starch
degradation has occurred. The water solubility values for milled samples decreased with
increasing fermentation time (Figure 9b).  The degree of degradation in parboiled samples and a
possibly more efficient amylase activity in this case, explained the increasing WSI values
recorded (Figure 9b) since the parboiling treatment was significant (p≤0.05) for all samples.
Studies by Kirby et al. (1988) and Makowska et al. (2013) also accredited the observation of
higher WSI results to starch degradation of extrudates but the latter acknowledged the
contribution of processing conditions (extrusion). According to Singh et al. (2010), foods with
high WSI values are easily digestible; a desired parameter of raw material for baby food
processing. Fermentation time effects were significant (p≤0.05) and corresponded negatively with
water solubility in the milled samples. This is because as fermentation time increased the
fermentable sugars present served as an energy source for microorganisms and therefore was
unavailable for water absorption and also there was an excess of starch that had not been broken
down. However, Lu et al. (2003) found that fermented rice samples produced higher water
solubility values in comparison with a control.
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4.2.2   Pasting Properties
Native starch does not interact much with cold water. But then as the water is heated to a specific
temperature characteristic of the starch source, the starch granule swells and absorbs water several
times the weight of the starch with a consequent increase in viscosity. This phenomenon is called
gelatinization or pasting and the temperature at which this occurs is referred to as the
gelatinization or pasting temperature. The starch pasting characteristics obtained for the fermented
rice-based samples is shown in (Table 4).
A0 A1 A2 A3 N.a.N. B0 B1 B2 B3
WS
I
0
4
8
12
16
c, d
d
a, b
a
a
d
c
d
d
Figure 9b Effect of fermentation time and parboiling treatment on water solubility index. A: milled
rice; B: parboiled rice. Similar lower-case letters shows differences are insignificant (p≥0.05).
0-zero hour fermentation
1-12 hour fermentation
2-24 hour fermentation
3-48 hour fermentation
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Peak viscosity (PV) is the highest measure of viscidness during gelatinization of starch granules
when heat is applied to slurry of a starch-based product. Some studies have suggested that peak
viscosity is influenced by the starch source and overall starch concentration (Sanstedt & Abbot,
1961; El-Dash et al., 1983). Peak viscosity values displayed by milled samples (Table 4) were
greater in magnitude (184-381 BU) than in parboiled samples (77-98 BU) because of the presence
of gelatinized starches in parboiled samples (Table 4). PV values increased with increasing
fermentation time in milled samples while in parboiled samples there was a declining trend. The
higher peak viscosity values observed in milled samples reflect a higher swelling potential that
increased with fermentation time. A similar observation has been hitherto reported by Saalia et al.
(2012). On the other hand, parboiled samples exhibited low PV values attributable to the presence
of gelatinized starch which increased susceptibility to degradation by the alpha amylase enzyme
added during processing of the fermented rice-based baby food product.
There was an overall increase in viscosity at 50 degrees hold for thirty minutes (trough viscosity)
and final viscosity at 95 ˚C at the end of the heating cycle in all samples with respect to
fermentation time (Table 4). Parboiled rice samples as compared with milled samples showed
relatively low viscosity at 50 degrees hold (trough viscosity) and final viscosity at 95 ˚C because
of the presence of pre-gelatinized starch granules. As fermentation time increased, both the trough
and final viscosities of milled samples increased and this agrees well to the study of Saalia et al.
(2012). Since trough viscosity and final viscosity indicates hot paste stability and paste
consistency respectively, the results obtained confirmed a better stability of milled rice starch
pastes with increasing fermentation time.
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When pasting temperatures are high, there is an increased resistance to swelling (Sandhu &
Singh; 2007). Generally, all samples recorded relatively low pasting temperatures (39-45°C)
(Table 4). Pasting/gelatinization temperatures were higher for parboiled samples than for milled
samples (Table 4) indicating that starch hydrolysis and solute concentration increases occurred at
a faster rate in the former as fermentation increased. Samples obtained from the milled rice
generally had lower pasting temperatures than those obtained for parboiled rice. For both groups
of samples, fermentation increased the pasting temperature (Table 4).  Parboiled samples had
higher gelatinization temperatures as compared to milled samples because the amylose that
leached out during the parboiling treatment recrystallized upon cooling and resulted in the
formation of firmer structure. Generally, low gelatinization temperatures observed in all samples
was favoured by fermentation and the drum-drying cooking process.
Breakdown values recorded for milled samples were relatively high and increased with
fermentation time (Table 4). The breakdown values for parboiled rice samples were generally
lower but also increased with fermentation time at lower rates. Breakdown measures the hot paste
stability under shear during cooking (Chiang & Yeh, 2002). Since the milled rice starches had
higher breakdown values, they may disintegrate more extensively than parboiled rice samples.
Similarly, since fermentation resulted in increases in the breakdown values of the starches,
fermented rice paste will be more easily disintegrated than non-fermented paste under shear
during cooking. The influence of fermentation on the shear stability of cooked paste could be
attributed to starch transformation by lactic acid bacteria (LAB).
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Setback viscosity (SV) is the degree of synaeresis of cooked starch paste upon cooling. Milled
samples recorded higher setback values (Table 4). This means that parboiled samples had a lower
tendency to undergo retrogradation. Miles et al. (1985) suggested that this could be as a result of
accumulation of amylose molecules due to retrogradation. The 24-hour fermented milled rice  had
the highest setback value of 201 BU. Research carried out by Wang et al. (2000) found that lower
retrogradation values corresponded with lower pH values in the processing of fermented rice
noodle. A similar trend was observed in the fermented baby food samples with discrepancies in
the 24-hour fermented milled and parboiled samples.
Table 4Pasting characteristics of fermented rice-based milled and parboiled products
Samples
(fermented
baby food)
Pasting/
Gelatini-
zation
temperature
(°C)
Peak
viscosity
(BU)
Peak
Tempera
-ture
(°C)
Trough
viscosity
(BU)
Final
viscosity
(BU)
Breakdown
(BU)
Setback
(BU)
A0 39.0 184.0 93.5 174.0 293.0 86.0 199.0
A1 39.0 315.0 93.4 292.0 306.0 192.0 185.0
A2 44.0 337.0 92.6 294.0 320.0 221.0 201.0
A3 44.0 381.0 93.5 364.0 301.0 260.0 181.0
B0 43.0 98.0 95.0 67.0 148.0 15.0 87.0
B1 43.0 88.0 94.4 88.0 150.0 22.0 84.0
B2 42.0 96.0 95.0 83.0 154.0 39.0 89.0
B3 45.0 77.0 94.9 76.0 139.0 21.0 84.0
0-zero hour fermentation time; 1-12hr fermentation time; 2-24hr fermentation time; 3-48hr
fermentation time; A-milled rice and B-parboiled rice.
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4.2.3   Pasting Profile
The Microviscoamylograph curves (Figures 10 and 11) show the pasting profile of milled rice and
parboiled rice respectively. Peak temperatures of all samples ranged between 93˚C and 95˚C.
When sample slurries were held at 95˚C for about 30 minutes, initial high peaks (peak viscosity)
were observed for milled samples while parboiled samples showed slight increases (Figure 10);
however the holding time led to decline in viscosities of milled samples while parboiled samples
kept constant viscosities at approximately 90 BU (Figure 11). The decrease in viscosities
observed in milled samples was as a result of the breakdown of the molecular framework of
starch and probably leaching of amylose during the holding time. This is an indication of hot
paste stability of parboiled samples; comparatively, milled products are therefore more likely to
give thinner pastes when boiling water is used for reconstitution. Lower viscosity increases were
also observed for parboiled samples during the cooling period showing lower susceptibility to
retrogradation.
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Figure 10 Microviscoamylograph showing pasting profile of fermented milled rice-based
product. 0-zero hour fermentation time; 1-12hr fermentation time; 2-24hr fermentation time; 3-48
hr fermentation time; b-parboiled rice.
time, min
10 20 30 40 50 60
vis
cos
ity,
 B. 
U.
0
100
200
300
400
tem
per
atu
re, 
°C
20
40
60
80
100
120
A0
A1
A2
A3
temperature
time, min
10 20 30 40 50 60
visc
osi
ty, 
B. U
.
0
100
200
300
400
tem
per
atu
re, 
°C
20
40
60
80
100
120
B0
B1
B2
B3
temperature
Figure 11 Microviscoamylograph showing pasting profile of fermented parboiled rice-based
products. 0-zero hour fermentation time; 1-12hr fermentation time; 2-24hr fermentation time; 3-
48hr fermentation time; B-parboiled rice.
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Protein Functionality of the Drum-Dried Fermented Rice-Based Baby Food Products
4.3.1 Protein Solubility
Rice proteins include: albumins, globulins, prolamins and glutelins (Juliano, 1994). Because these
proteins are soluble in different solvents, their solubilities in diverse buffer systems can be
measured (Iametti et al., 2006). Table 5 shows the solubility of proteins from the drum-dried
products in different buffer systems. Generally, in all the three buffer systems, protein solubility
increased with fermentation time until twelve hours. Thereafter it decreased through to 48 hours
fermentation time. Milled rice proteins were more soluble than those in parboiled rice probably
because of heat denaturation of the proteins in parboiled rice. The observed decrease in solubility
after 12 hours corresponded to decreases in the pH of the medium suggesting that fermentation
produced acids that precipitated proteins out of solution. In the saline buffer, some proteins
dissolved at zero fermentation time (Figures 12 and 13).These are most probably proteins that are
soluble in neutral salt conditions, such as globulins (deMan, 1999). From Figures 12 and 13, it
was observed that solubility of proteins in saline buffer was very low in milled samples and even
much lower in the case of parboiled samples. This trend was observed in all three buffer systems
(Figures 12 and 13). Urea, a denaturing solvent, was added in order to solubilize protein
aggregates.  In the urea-saline buffer, it was observed that rice proteins turned out to be about
three times more soluble for milled rice and about five times more soluble for parboiled rice
(Table 5). This was because the urea-saline buffer was able to disrupt the structured protein
network in all products stabilized by hydrophobic interactions. This is comparable to a study by
Cabrera-Chávez et al. (2012) involving amaranth-enriched, gluten-free rice pasta where similarly,
the addition of urea increased the protein solubility. The third buffer which contained dithrethiol
(DTT) in addition to urea and salts gave the highest protein solubility values in all products
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(Table 5, Figures 12 and 13). Essentially, in certain cereals such as corn and rice, proteins present
are rich in sulfurous amino acids namely, methionine and cysteine (deMan 1999, Fennema, 1996).
Consequently, DTT cleaved the disulphide bonds in the rice proteins and converted them into
sulfhydryl groups, removing the last traces of the quaternary or tertiary protein structure of the
proteins. Formation of disulphide bonds between the peptides and the extraction medium
instigated the protein solubility increases. This agrees with a study by Mariotti et al. (2011).
In all three buffers, a decrease in protein solubilities was observed at fermentation times 24 and
48 hours respectively (Table 5, Figures 12 and 13). This means that after twelve hours of
fermentation, proteins precipitated out of solution due to increasing acidity as a result of
fermentation. It is possible that the isoelectric point of the rice proteins present was close to pH
after 12hours of fermentation (pH~3.6). The isoelectric point (pI) of rice proteins is reported to be
approximately pH 4 (Nehete et al., 2013). When DTT was added, however, the protein solubility
increases observed confirmed that interprotein disulphide bonds were formed in addition to
hydrophobic interprotein interactions in samples that underwent parboiling treatment. Barbiroli et
al. (2013) obtained similar results in his study involving the use of parboiled rice flour and
untreated rice flour as raw materials for making pasta. Fermentation and treatment effects were
significant for all buffer systems except for the Buffer C system which was not significantly
affected by parboiling treatment (p≥0.05).
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solu
ble 
pro
tein
s, m
g/g 
sam
ple
0
10
20
30
40
50 A0
A1
A2
A3
buffer        + urea     + urea/DTT
Rice Type Fermentation
time
Saline Buffer +Urea +Urea/DTT
Milled Rice 0 1.9±0.3b 6.5±0.3a,b 27.7±1.0b
12 6.2±0.5d 16.2±1.0d 64.6±3.5d
24 5.0±0.2c 11.0±0.5c 29.1±21.8c
48 4.3±1.1c 9.9±1.6b 16.0±3.5a
Parboiled
Rice
0 0.8±0.1a 4.1±0.2a 24.4±1.0b,c
12 1.6±0.1a 8.3±0.3b 60.4±1.8d
24 0.6±0.1a 4.6±0.3a 19.0±0.6a
48 0.8±0.1a 5.0±0.1a 10.9±1.8a
Table 5 Protein solubility of drum-dried fermented rice-based baby food samples.
Milled
Figure 12 Protein solubility in different buffer systems for drum-dried milled fermented rice
samples. Values with same lower case letters are not significantly different (p≥0.05).
*Values with same lower case letters are not significantly different (p≥0.05)
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4.3.2 Thiol Accessibility Studies
Thiol accessibility was carried out to find out the total amount of reactive protein thiols (measured
under denaturing conditions on both the soluble and insoluble fraction) and the change in thiol
accessibility owing to denaturation. This experiment was carried out to ascertain the extent of the
effect of processing procedures on the proteins in cereal-based products. Similar experiments
have been reported by Cabrera-Chávez et al. (2012). Elkhalifa et al. (2006) and Mariotti et al.
(2011). As illustrated in Figures 14 and 15, parboiled rice-based products showed a slightly
higher amount of accessible thiols than milled rice samples both in the presence and absence of
the chaotrope (urea). However, Barbiroli et al. (2013) observed lower amounts of accessible
thiols both in the absence and presence of urea in pasta products made with parboiled rice flour.
The variation in the study results could be attributed to the role of fermentation time. During
solu
ble 
pro
tein
s, m
g/g 
sam
ple
0
10
20
30
40
50 B0
B1
B2
B3
buffer        + urea     + urea/DTT
Parboiled
Figure 13Protein solubility in different buffer systems for drum-dried parboiled fermented rice
samples. Values with same lower case letters are not significantly different (p≥0.05).
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fermentation, the proteins in the milled and parboiled rice-based samples were subjected to
hydrolysis by the microbial proteases apart from the alpha amylase enzyme that was added in the
formulation. Even though parboiling treatment denatured proteins, because this rice-type was
more susceptible to hydrolysis, increasing fermentation time provided an acidic environment with
the release of more H+ (hydrogen) ions and thus more –SH bonds were formed and this explains
accessible thiol increases in parboiled samples which increased slightly on the addition of urea.
In the case of milled samples, there was a decline in the amount of accessible thiols after 12 hours
of fermentation in the presence and absence of urea (Figure 16). The lower pH environment
created after twelve hours of fermentation may have caused rice proteins to precipitate out of
solution indicating that the pH of samples at fermentation times 24hr and 48hr are close to the
isoelectric point of some of the rice proteins. Fermentation time and parboiling interactions were
significant (p-value≤0.05) for the saline buffer. The high-temperature processing technique, that
is, drum-drying, in addition to parboiling treatment did not create a rigid structure of protein
aggregates otherwise expected demonstrating that over here the fermentation process played a
very significant role irrespective of heat denaturation of proteins (p≤0.05). Slight increases in
accessible thiols due to addition of urea, a denaturing agent was also observed.
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Figure 4.3.2.1 1
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Saline Buffer Urea+SalineBuffer
acc
esi
ble
 th
iols
, μ
mo
l/g
 sa
mp
le
0hr
12hr
24hr
48hr
Parboiled
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Saline Buffer Urea+Saline Buffer
acc
ess
ible
 th
iols
 μm
ol/
g s
am
ple
0hr
12hr
24hr
48hr
Milled
Figure 14 Accessible thiols in proteins of fermented milled rice-based baby food products.
Figure 15 Accessible thiols in proteins of fermented parboiled rice-based baby food products.
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4.3.3Sodium Dodecyl Sulfate Polyacrylamide-Gel Electrophoresis (SDS-PAGE) Patterns of
Rice Proteins
The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) patterns of proteins
obtained from the rice-based products were compared with bands that corresponded to standard
molecular weights of proteins. SDS-PAGE investigated the formation of disulfide-linked soluble
rice protein aggregates and provided information on the molecular characterization of specific
protein fractions in different solvent extracts of the fermented rice samples in the presence of 2-
mercaptoethanol. There was a general observation of three bands corresponding to proteins of
molecular weights 14kDa, 30kDa and 45kDa respectively in both  milled and parboiled rice
samples (Figure 16 and 17). It was observed that most of the proteins in milled samples were
hydrolyzed by the 12th hour of fermentation. Parboiled rice proteins took a longer fermentation
time to hydrolyze because of the formation of more aggregates in this sample (Figure 17).
Predictably, the presence of a chaotrope (urea) and a reducing agent resulted in the formation of
aggregates which diminished with increasing fermentation time. In all samples, proteins at lower
molecular weights (˂45kDa) were made visible after disulphide-linkage protein aggregation in
Buffer C (i.e. sodium phosphate-saline buffer with urea and dithrethiol), (Figures 16 and 17)
confirming the presence of globulins (M~12-45kDa) (Sulieman et al., 2008). It was also noticed
that similar proteins were solubilized from all samples irrespective of the rice treatment (parboiled
or non-parboiled) (Figures 16 and 17). A low molecular protein (M~14kDa) band was seen to
constantly appear in saline-urea buffer (Buffer B) for milled samples (Figure 16) but was
however not seen in parboiled samples (Figure 17). This could be an indication of the presence of
basic proteins such as glutelins (deMan, 1999). Presumably, the parboiling treatment produced
more digested proteins which were apparently involved in disulphide bonds as seen in Buffer C
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(sodium phosphate-saline buffer, urea and dithrethiol) .Similarly, Mariotti et al. (2011) explained
that urea-soluble proteins extracted from gluten-free rice and maize pasta take part in forming
disulfide-linked aggregates. For the milled samples, the clear appearance of the three protein
bands at 14kDa, 30kDa and 45kDa respectively in Buffer C at 48hour fermentation time
(Figure17) was also as a result of more disulphide bridges due to the proliferation of sulfhydryl
residues in the increasing acidic environment during fermentation. As illustrated in Figure 17,
parboiled samples, showed clearly visible protein bands in buffer C (sodium phosphate-saline
buffer, urea and dithrethiol). Because parboiled samples were more susceptible to digestion by
enzymes, most of proteins were digested. As fermentation proceeded, increasing acidic
environment also aided denaturation and formation of aggregates with corresponding disulphide
linkages. By 48hours fermentation time, most of the proteins had been broken down to
polypeptide units with very low molecular weights that could not be retained by the gel.
kDa
96-
65-
45-
30-
21-
14-
Figure 16 SDS-PAGE patterns of proteins in milled fermented rice-based baby food products. M:
Marker. A: sodium phosphate-saline buffer, B: sodium phosphate-saline buffer and urea, C:
sodium phosphate-saline buffer, urea and dithrethiol. Denaturation of samples were carried out in
the presence of 1% (v/v) 2-mercaptoethanol.
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4.4 In vitro Digestibility Studies
4.4.1 Protein Digestibility by pepsin and pancreatin
In vitro protein digestibility is a more convenient method to ascertain the in vivo digestibility of
protein because recruitment of human subjects is not required and its measurement involves a
relatively lesser period of time. Protein digestibility defines protein quality for the reason that it
gives information on the amino acid availability profile (Hahn et al., 1982). Protein digestion
kDa
96-
65-
45-
30-
21-
14-
M A B C
Figure 17 SDS-PAGE patterns of proteins in parboiled fermented rice-based baby food
products. M: Marker; A: sodium phosphate-saline buffer, B: sodium phosphate-saline buffer
and urea, C: sodium phosphate-saline buffer, urea and dithrethiol. Denaturation of samples were
carried out in the presence of 1% (v/v) 2-mercaptoethanol.
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begins in the stomach where the enzyme pepsin which requires a low pH for activity plays a
major role.
This experiment began within initial enzyme (pepsin) activity for an hour. After 60 minutes of
pepsin activity, slight digestion of proteins was observed (Figures 18 and 19) but there were no
statistical differences between all samples. Protein digestibility by pepsin was significantly
slightly higher in milled than in parboiled samples with respect to significant increases in
fermentation time (p≤0.05). Pancreatin was introduced after 60 minutes and there was a
remarkable increase in rice protein hydrolysis. This agrees with a study carried out by Petitot et
al. (2009) on wheat protein from dry pasta. Under the same conditions, fermentation showed
significant influence on the hydrolysis of proteins by both pepsin and pancreatin. Increasing
fermentation time for both milled and parboiled samples showed increasing susceptibility to
protease hydrolysis of the rice proteins. On the whole, the 48 hour fermented rice samples showed
higher protein digestibilities for all samples followed by the 24-hour fermentation period.
Fermentation time significantly affected the protein digestibility in both milled and parboiled rice.
Though the 12 hour fermented samples recorded the least protein digestibility values, it did not
significantly differ from the 0-hour fermented samples (p≥0.05) at the initial stages of pancreatic
activity (90 minutes). The highest peak of protein digestibility was recorded at time 180 minutes
after pancreatic digestion where there were significant differences among samples except between
the zero and twelve hour-fermented samples for both milled and parboiled samples (Figure 18 and
19). Digestibility of proteins have recently gained attention because it has been found to
positively influence the rate of starch digestibility in rice-based products (Mujoo & Ali, 1998).
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-0.5
0
0.5
1
1.5
2
0 50 100 150 200 250 300
A
bs
o
rb
a
n
ce
Time(minutes)
0hr
12hr
24hr
48hr
Milled
0
0.5
1
1.5
2
0 50 100 150 200 250 300
A
bs
o
rb
a
n
ce
Time(minutes)
0hr
12hr
24hr
48hr
Parboiled
Pepsin                              Pancreatin
Pepsin                              Pancreatin
Figure 18 Effect of processing on the in vitro protein digestibility of drum-dried fermented
parboiled rice-based baby food
Figure 19 Effect of processing on the in vitro protein digestibility of drum-dried fermented
parboiled rice-based baby food
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4.4.2 Starch Digestibility and Free Sugars Determination
4.4.2.1 Rapidly/Readily Digestible Starch (RDS), Slowly Digestible Starch (SDS) and
Glycaemic Index
Most cereal-based baby foods are starch-rich therefore starch metabolism following consumption
is of grave interest. Starch digestibility of fermented rice-based products was estimated by
measuring the rapidly/readily digestible starch (RDS), slowly digestible starch (SDS) and over all
glycaemic index. From Table6, it was observed that readily digestible starch values were high
while on the other hand, low levels of slowly digestible starch were obtained for both milled and
parboiled rice. This confirms that rice is highly digestible. Recent findings have established the
benefits of consuming foods high in slowly digestible starch because it allows for steady increase
of plasma glucose and insulin levels after few hours’ consumption (Jenkins et al., 1982; Wolever
& Mehling, 2002). However, very high or very low levels of non-digestible carbohydrate in
infants have not been well studied though they impact the health of infants over a long period of
time (Agett et al., 2003). Overall, predicted glycaemic indices were high in all samples with the
48hr fermented samples of milled and parboiled rice recording the highest glycaemic values
(Table 6). This confirms the relationship between the extent of breakdown of starch to glucose
and the fermentation period even though high heat processing treatment such as drum drying has
also been reported to increase starch digestibility (Sindhu & Khetarpaul, 2001). There were,
however, no statistically differences between glycaemic indices of samples. Readily digestible
starch values were relatively higher in milled samples than in parboiled samples. This means that
there were still some sugars present in milled samples while those in the parboiled samples had
already been used up by microorganisms. Reduction in slowly digestible starch as shown in the
48hr fermented milled and parboiled samples negatively corresponded to the higher glycaemic
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indices observed in the 48-hour fermented milled and parboiled rice. Chung et al. (2011) reported
that long grain rice recorded lower RDS and corresponding higher SDS. Thus, higher RDS and
lower SDS values obtained could be attributed to the short, broken nature of rice grains used in
this study.
Sample Fermentation
time/hours
Ready digestible
starch/ %
Slowly digestible
starch/%
Predicted
Glycaemic
Index
A0 0 89.3 ±2.7a 2.4 ±0.4a 89.7
A1 12 85.3 ±0.2a 2.7 ±0.3a 89.3
A3 48 87.0 ±0.1b 1.5 ±0.3b 91.0
B0 0 83.9 ±1.0a 2.8 ±0.5a 89.2
B1 12 83.7 ±4.5a 2.7 ±0.4a 89.3
B3 48 80.9 ±0.7b 0.6 ±0.2b 92.0
Table 6 Estimated mean values for RDS, SDS and Predicted Glycaemic Index. A: milled, B: parboiled.
RDS-readily or rapidly digestible starch; SDS, slowly digestible starch. A-milled rice; b- parboiled
rice; 0-zero hour fermentation time; 1-12 hour fermentation time; 2-24 hour fermentation time; 3-48
hour fermentation time. Values followed by different superscripts in the same column are significantly
different (p≤0.05).
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4.4.2.2 Free Sugars in Rice
Starch digestibility is followed by the release of simple or free sugars which form is assimilated
into the bloodstream. From Figures 20 and 21, it was observed that maltose and glucose sugars
were present in both milled and parboiled rice.  Lactose levels were negligible and was observed
as a result of enzymes and solvents used in the analytical procedure. Higher levels of free sugars
were observed in the milled rice samples as compared to the parboiled samples. Trace levels of
maltose observed was as a result of the presence of residual dextrin in the samples which
diminished after zero hour fermentation (Figures 20 and 21). In the milled samples, the 12-hour
fermented sample recorded the highest glucose content followed by the zero-hour fermented
sample. The reduction in glucose concentration observed in the 48-hour fermented milled rice
(Figure 20) suggests that by that fermentation period, the microorganisms began to use up some
of these sugars for their activities. This observation agrees well with Saalia et al. (2012).
free
 sug
ars,
 (g/1
00g
 d.m
.)
0
2
4
6
8 A0
A1
A3
lactose           glucose             maltose
n.d. n.d.
Figure 20 Free sugars present in fermentation milled rice-based product. A-milled rice 0-zero
hour fermentation time; 1-12 hour fermentation time; 3-48 hour fermentation time.
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4.5 Sensory Evaluation
When a product is developed in food processing, the qualitative features such as the appearance,
aroma, flavour, texture and after-taste could be identified using a list of descriptors developed by
a trained panel who in turn attempt to measure each perceived attribute on a scale, for example, a
15-cm scale. This is termed descriptive sensory evaluation and an example is using the
quantitative descriptive analysis (QDA) technique (Stone et al., 1974; Stone & Sidel, 2004).
Recently, e-sensing instruments have also become useful in descriptive sensory evaluation and
have reported use in several publications (Peris & Escuder-Gilabert, 2009; Escuder-Gilabert,
2010; Winquist et al., 1998).In this study, descriptive sensory analysis was carried out using the
quantitative descriptive analysis (QDA) process and the electronic nose and electronic tongue
(instrumental e-sensors).
free
 sug
ars 
(g/1
00 g
 d.m
.)
0
2
4
6
8 B0
B1
B3
lactose           glucose             maltose
n.d. n.d.
Figure 21 Free sugars present in fermentation milled rice-based product. B-parboiled rice 0-zero
hour fermentation time; 1-12 hour fermentation time; 3-48 hour fermentation time.
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4.5.1 Quantitative Descriptive Analysis
Results from the quantitative descriptive analysis were illustrated by the sensory profiles
described in the following figures (Figures 22 to 45).
4.5.1.1 Sensory profile description of fermented rice –based products (in powdery form)
Figure 22&23, 24&25, 26&27 and 28&29 show the sensory profile of milled and parboiled
products in a spider-web graphical representation where the zero point of the descriptor scale is
the mid-point, with the intensity increasing in the direction of the extremities. The mean value of
each descriptive term was marked in the respective axis, and the sensory profile was drawn by the
connection of the points. The intensities of attributes were rated by panelists using a 15cm scale
from least (0cm) to extreme (15cm).
Both milled and parboiled samples were generally dry and creamy (Figures 22 and 23). The 24-
hour fermented sample was the most creamy for milled rice but was most white in parboiled
samples. Also while the zero hour fermented sample showed the most uneven and particulate
surface appearance for parboiled samples, in the case of milled products, it was the 12 hour
fermented sample (Figures 22 and 23). Significant differences observed between samples
depended on whether products were milled or parboiled products for colour attributes (p-
value=0.00) but fermentation time effects were not significant except between 0 and 12 hours of
fermentation. Fermentation time did not affect surface dryness; however, it affected products’
particulate surface appearance at a p≤0.05. Also, the parboiling treatment significantly affected
dryness atp≤0.05but for the particulate descriptor, there were no significant differences. Almost
all sample products were perceived as dry (Figures 22 and 23) with mean values range (10.5≤ x
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≤12.2). There was also a significant positive correlation between the cream colour and fermented
flavour (0.340*).
Aroma attributes are illustrated in Figures 24 and 25. It was observed that milled samples had
more pronounced aroma intensities particularly the starchy attribute recorded by the 48hour
fermented milled rice. Zero-hour fermented samples for both milled and parboiled rice had the
most ricey aroma and the least fermented aroma. This explains why fermented aroma intensity
corresponded negatively with ricey aroma in almost all products (-0.434*). The 24-hour
fermented sample had the most fermented aroma for milled rice while 12-hour fermented sample
had the most fermented aroma for parboiled rice.  24-hour sample had the most maize-like aroma
and the least cardboardy aroma for both milled and parboiled rice. The effects of fermentation
time on the intensities of ricey and cardboardy attributes were significant. There was a positive
correlation between starchy and cardboard (0.405*) aromas and also between fermented aroma
and fermented flavour (0.583*). The asterisks (*) is an indication significant of difference.
The most significantly pronounced flavour attributes were sour, fermented, sour-aftertaste and
rich flavour recorded by the 48-hour fermented sample for milled rice and 12-hour fermented
sample for parboiled rice (Figures 26 and 27). The parboiling treatment resulted in weaker
intensities of the flavour attributes (Figure 27). As expected, fermentation time significantly
augmented the fermented flavour and sourness thereby diminishing the sweet-aftertaste (p≤0.05).
This explains the strong correlation between sour and fermented flavour (0.598*). The fermented
flavour also significantly correlated well with the fermented aroma (0.583*). The 24 hour
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fermented sample had the most maize/corn flavour for both milled and parboiled rice and this is
analogous to the maize-like aroma obtained by the same sample.
Texture attributes were obtained using the mouth-feel and touch sensation for both milled and
parboiled products. Differences between all texture attributes were significantly different between
milled and parboiled samples except for the flaky texture. Parboiled products demonstrated lower
intensities for almost all texture attributes (Figures 28 and 29). Also fermentation time did not
significantly affect texture attributes, except for the particulate (touch sensation) and flaky
qualities. Because these products were assessed by panelist in powdery form, it is not surprising
that the dry texture was the most distinct texture attribute for both milled and parboiled products
(Figures 28 and 29). There was also a strong positive correlation between gritty and particulate
descriptors (0.561*).
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0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
white
cream
beige
dryparticulate
uneven
crystalline
0hr
12hr
24hr
48hr
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
white
cream
beige
dryparticulate
uneven
crystalline
0hr
12hr
24hr
48hr
Milled
Parboiled
Figure 22 Sensory profile showing appearance attributes of fermented milled rice-based
products (powdered form)
Figure 23 Sensory profile showing appearance attributes of fermented parboiled rice-based
products (powdered form).
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Figure 4.5.1.1.2a 1
Figure 4.5.1.1.2a 2
0.0
1.0
2.0
3.0
4.0
5.0
maize-like
starchy
fermentedcardboardy
ricey
0hr
12hr
24hr
48hr
0.0
1.0
2.0
3.0
4.0
5.0
maize-like
starchy
fermentedcardboardy
ricey
0hr
12hr
24hr
48hr
Milled
Parboiled
Figure 24 Sensory profile showing aroma attributes of milled fermented rice-based
products (powdered form)
Figure 25 Sensory profile showing aroma attributes of fermented parboiled rice-based
products (powdered form)
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Figure 26 Sensory profile showing flavour attributes of fermented milled rice-based
products (powdered form)
0.0
2.0
4.0
6.0
8.0
10.0
rich
sweet
maize/corn
sour
blandfermented
ricey
sweet after-
taste
sour after-taste
0hr
12hr
24hr
48hr
Figure 4.5.1.1.2a 3
Figure 4.5.1.1.2a 4
0.0
2.0
4.0
6.0
8.0
10.0
rich
sweet
maize/corn
sour
blandfermented
ricey
sweet after-
taste
sour after-
taste
0hr
12hr
24hr
48hr
Milled
Parboiled
Figure 27 Sensory profile showing flavour attributes of fermented parboiled rice-based products
(powdered form)
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0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
particulate (mouthfeel)
gritty (mouthfeel)
crunchy (mouthfeel)
particulate (touch
sensation)gritty (touch sensation)
dry (touch sensation)
flaky (touch sensation)
0hr
12hr
24hr
48hr
Figure 29 Sensory profile showing texture attributes of fermented parboiled rice-based
products (powdered form).
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
particulate
(mouthfeel)
gritty (mouthfeel)
crunchy (mouthfeel)
particulate (touch
sensation)
gritty (touch
sensation)
dry (touch sensation)
flaky (touch
sensation)
0hr
12hr
24hr
48hr
Milled
Parboiled
Figure 28 Sensory profile showing texture attributes of fermented milled rice-based products
(powdered form).
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Table 7List of sensory descriptors and definitions for fermented rice-based products (powdery
form)
MODALITIES Descriptors Definition
1. APPEARANCE
a. Colour White Colour related to white corn grits (‘eko egbemi’)
REF: white corn grits
Cream Colour  exhibited in cheese (laughing cow cheese)
REF: laughing cow cheese
Beige Pale yellowish-brown colour
REF: Heinz salad cream
b. Surface texture Particulate Discrete/minute separate powdery particles
REF: milled raw rice
Crystalline Relating to the reflectiveness/glassy surface of the
particles
REF: broken glass pieces
Uneven A mixture of non-uniform particles with rough ridges
REF: sand particles
2. AROMA Maize-like Unsweetened corn porridge
REF: corn porridge without sugar
Starchy Distinct uncooked cereal starch
REF: corn dough in cold water
Fermented Related to cooked sour corn dough
REF: cooked ‘kenkey’ and ‘banku’
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Cardboardy Related to a stack of stored packed cartons/boxes
REF: stack of stored boxes made of cardboard
Ricey Uncooked milled non-perfumed rice
REF: uncooked raw rice
3. FLAVOUR Rich Strong intense full flavour
cassava grits (Gari) without sugar
Ricey Uncooked milled non-perfumed rice
REF: uncooked raw rice
Sour Related to citrus acids
REF: lemon juice
Maize/corn Oven- roasted  maize flour
REF: roasted maize flour (tom-brown)
Fermented Related to cooked sour dough
REF: mixed flavour from kenkey and banku
Sweet Relating to sugar
REF: granulated sugar
Bland Related to tasteless flavour (like clean drinking
water)
REF: clean lukewarm water
4. AFTERTASTE Sour Biting taste after swallowing
REF: lemon juice
Sweet Relating to sugar
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REF: granulated sugar solution
5. a. TEXTURE
(mouth feel) Particulate Discrete/minute separate powdery particles
REF: milled uncooked raw rice
Crunchy Snaps when bitten into
REF: cream cracker biscuit
Gritty Feels sandy in the mouth with uniform ridges as
related to cooked corn grits
REF: cooked  corn grits
b.TEXTURE
(touch sensation) Gritty Particles with sharp ridges when rubbed with the
fingers
REF: uncooked  corn grits
Particulate Discrete/minute separate powdery particles
REF: uncooked raw rice
Dry Has very low moisture content
REF: dry powder
Flaky Small flat-disked thin pieces
REF: broken corn flakes pieces
REF: Reference food
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4.5.1.2 Sensory profile description of fermented rice –based products (in re-constituted
form)
Upon reconstitution with water, both milled and parboiled became smooth and pasty (Figures 30
and 31). The intensities of the white colour appearance attribute was also enhanced after
reconstitution with water. However this colour decreased significantly with fermentation time but
significantly increased after 24 hour fermentation period (p≤0.05). The 48-hour fermented sample
recorded the highest value for white colour in parboiled samples while for the milled rice, 0-hour
fermented sample had the highest value for white colour followed by 48-hour fermented sample.
Milled samples had a more creamy colour than parboiled samples. Parboiling and fermentation
resulting in obtaining a smoother surface appearance (Figure 31). 48-hour fermented sample was
smooth in parboiled rice but pasty in milled rice while the 24-hour fermented sample was least
smooth in milled and least pasty in parboiled. The same sample was also the most pulpy in milled
and least pulpy in parboiled samples. Overall, parboiling treatment effects was not significant for
all descriptors used for re-constituted products (p≥0.05). Obviously, all samples recorded higher
intensities for pasty and smooth appearance but differences among samples were not statistically
significant (p≥0.05).
Reconstitution with water significantly reduced starchy, ricey and cardboardy aroma notes and
enhanced maize-like and fermented aroma notes in both milled and parboiled sample (Figures 32
and 33).  The fermented aroma significantly increased as fermentation proceeded. Products that
recorded high intensities for fermented aroma presented corresponding low ricey aroma
intensities (Figures 32 and 33). This explains why ricey aroma decreased significantly with
increasing fermentation time (p≥0.05). The 48-hour fermented sample showed the most fermented
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aroma for milled rice while 24 –hour fermented sample showed the most fermented aroma for
parboiled samples.
The 48hr fermented samples recorded higher intensities for fermented, sour, rich, maize-like
flavours and sour after-taste for both milled and parboiled samples (Figures 34 and 35). The
fermented flavour significantly increased with increasing fermentation time. An observed strong
positive correlation (0.267*) between fermented flavour and fermented aroma was statistically
significant. This observation was similar to sour and sour-aftertaste flavour attributes (0.247*). As
observed with aroma attributes; ricey flavour significantly decreased with fermentation time
increases (Figures 34 and 35) and was significantly negatively correlated with the fermented
flavour (-0.136*). The zero-hour fermented sample had the most ricey flavour for both milled and
parboiled rice. Rich flavour also correlated well with fermented (0.614*) and starchy flavours
(0.412*) (p≤0.05). The asterisks (*) is an indication of significance of difference.
With the texture of products, the 48hr fermented milled rice product presented higher intensities
for all texture attributes (Figure 36 and 37) while for parboiled samples, differences between
texture attributes  owing to the mouth feel was not clearly defined (Figure 37). Apart from the
differences clearly shown for the pasty owing to touch sensation attribute among products for
both milled and parboiled rice which significantly increased with fermentation time (p≤0.05); the
rest of the texture attributes were not significantly different from each other. There was a
significant strong positive correlation between sticky texture (touch sensation) and fermented
aroma, fermented, rich, starchy and sour flavours (p≤0.05). The 12-hour fermented sample was
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soft owing to touch sensation for both milled and parboiled samples. The 48-hour fermented
sample showed the most gritty texture owing to mouth-feel for milled samples while the zero-
hour fermented sample showed the most gritty texture owing to mouth-feel for parboiled rice.
Figure 4.5.1.1.2a 5
Figure 4.5.1.1.2a 6
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
white
cream
beige
pastypulpy
soft
smooth
0hr
12hr
24hr
48hr
Milled
Figure 4.5.1.1.2a 7
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
white
cream
beige
pastypulpy
soft
smooth
0hr
12hr
24hr
48hr
Parboiled
Figure 30 Sensory profile showing appearance attributes of fermented milled rice-based
products (re-constituted form)
Figure 31 Sensory profile showing appearance attributes of fermented parboiled rice-based
products (re-constituted form)
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Figure 32 Sensory profile showing aroma attributes of fermented milled rice-based
products (re-constituted form)
0.0
2.0
4.0
6.0
8.0
10.0
maize-like
starchy
fermentedcardboardy
ricey 0hr
12hr
24hr
48hr
Milled
Figure 4.5.1.1.2a 8
0.0
2.0
4.0
6.0
8.0
10.0
maize-like
starchy
fermentedcardboardy
ricey 0hr
12hr
24hr
48hr
Parboiled
Figure 33 Sensory profile showing aroma attributes of fermented parboiled rice-based products (re-
constituted form)
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Figure 34 Sensory profile showing flavour attributes of fermented milled rice-based products
(re-constituted form)
0.0
2.0
4.0
6.0
8.0
10.0
rich
sweet
maize/corn
sour
blandfermented
ricey
sweet after-taste
sour after taste
0hr
12hr
24hr
48hr
Milled
Figure 4.5.1.1.2a 9
Figure 4.5.1.1.2a 10
0.0
2.0
4.0
6.0
8.0
10.0
rich
sweet
maize/corn
sour
blandfermented
ricey
sweet after-taste
sour after taste
0hr
12hr
24hr
48hr
Parboiled
Figure 35 Sensory profile showing flavour attributes of fermented parboiled rice-based
products (re-constituted form)
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Figure 4.5.1.1.2a 11
0.0
2.0
4.0
6.0
8.0
10.0
12.0
smooth (mouth
feel)
gritty
(mouthfeel)
pulpy
(mouthfeel)
pasty (mouth
feel)
sticky (touch
sensation)
pasty (touch
sensation)
gritty (touch
sensation)
soft (touch
sensation)
0hr
12hr
24hr
48hr
Milled
Figure 4.5.1.1.2a 12
0.0
2.0
4.0
6.0
8.0
10.0
12.0
smooth (mouth
feel)
gritty
(mouthfeel)
pulpy
(mouthfeel)
pasty (mouth
feel)
sticky (touch
sensation)
pasty (touch
sensation)
gritty (touch
sensation)
soft (touch
sensation)
0hr
12hr
24hr
48hr
Parboiled
Figure 36 Sensory profile showing texture attributes of fermented milled rice-based products
(re-constituted form)
Figure 37 Sensory profile showing texture attributes of fermented parboiled rice-based products
(re-constituted form)
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MODALITIES Descriptors Meaning/Definition
1. APPEARANCE
c. Colour
White Colour related to white corn grits(‘eko
egbemi’)
REF: white corn grits
Cream Colour exhibited in cheese
REF: laughing cow cheese
Beige Pale yellowish-brown colour
REF: Heinz salad cream
d. Surface texture Pasty Molten like cooked white corn grits porridge
REF:  cooked white corn grits porridge
Smooth Uniform consistency
REF: smooth paste of Bird’s custard
Soft Texture relating to blended Ga kenkey (‘ice
kenkey’) paste
REF:  Blended Ga kenkey (‘ice kenkey’)
paste
Table  8List of sensory descriptors and definitions for fermented rice-based products (re-constituted).
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Pulpy Mushy, semi-solid consistency
REF: a fruit smoothie (blended banana)
2. AROMA Maize-like Unsweetened corn porridge
REF: cooked corn porridge without sugar
Starchy Distinct uncooked cereal starch
REF: fresh milled corn dough
Fermented Related to cooked sour corn dough
REF: fermented corn dough
Cardboardy Related to a stack of stored packed
cartons/boxes
REF: packed boxes of cardboard
Ricey Uncooked milled non-perfumed rice
REF: milled raw rice
3. FLAVOUR Rich Strong intense full flavour
REF: cassava grits without sugar
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Ricey Uncooked milled non-perfumed rice
REF: milled raw rice
3. FLAVOUR Sour Related to citrus acids
REF: lemon juice
Maize/corn Oven- roasted  maize flour
REF:  Oven- roasted  maize flour
Fermented Related to cooked sour dough
REF: mixed flavour of Ga ‘kenkey’ and
‘banku’
Sweet Relating to sugar
REF: Sugar
Bland Related to tasteless flavour
REF: Clean lukewarm water
4. AFTERTASTE Sour Biting taste after swallowing
REF: lemon juice
Sweet Relating to sugar
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REF: granulated sugar solution
5. a. TEXTURE (mouth
feel)
Smooth Uniform consistency
Uncooked smooth paste of Bird’s custard
Gritty Feels like sandy paste in the mouth with
uniform
ridges as related to cooked corn grits
REF: dry cassava grits
Pulpy Mushy, semi-solid consistency as related to a
fruit smoothie
REF: blended banana
Pasty Molten in the mouth like cooked white corn
grits porridge
REF: cooked white corn grits porridge
b.TEXTURE
(touch)
Sticky Adhesive to touch with sticky surface
REF: cooked corn grits
Pasty Molten to touch like cooked white corn grits
porridge
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4.5.2 Sensory evaluation using E-sensors (electronic nose and electronic tongue)
Instrumental sensory evaluation of aroma attributes were carried out using the electronic nose and
the electronic tongue was used for the flavour attributes respectively in the step-wise procedure
described in Figure 38.
Figure 38 Step-wise procedure for electronic tongue sensory evaluation
REF: cooked white corn grits porridge
Soft Texture relating to blended Ga kenkey (‘ice
kenkey’) paste
REF: blended Ga kenkey (‘ice kenkey’) paste
Gritty Feels like sandy paste to touch with uniform
ridges as related to cooked corn grits
REF: cooked corn grits
Measuring Reference solution (Vr)
Measuring Sample solution (Vs)
Cleaning with Reference solution for 6s
Measuring Reference solution (Vr’)
Cleaning with Washing and Reference solution for 270 s
Vs-Vr=relative value
Vr’-Vr=CPA value
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4.5.3 Principal Component Analysis (PCA)
The Principal Component Analysis (PCA) was used to establish the variation and correlation
between attributes for aroma and flavour descriptors using data obtained from the quantitative
descriptive analysis and e-sensing (electronic nose and electronic tongue) measurements. Four
principal components were generated (PC1, PC2, PC3, PC4) in the scree plot and eingen values
obtained. One-way analysis of variance (ANOVA) was used to identify the significant principal
components: principal component 1 (PC1) and principal component two (PC2)which were used
for illustration and evaluation of the scores and loadings plot (Figures 38-45). The model was
based on 50.9%variation among the aroma attributes and 58.7% variation among the flavour
attributes for QDA respectively and 84.7% and 75.8% of the total variance for the electronic nose
and tongue respectively. Inthe PCA plots attributes and/or samples close to each other in the same
quadrant are correlated. The loadings plotusually helps to elaborate the score plot. Discrimination
of products along the second principal component is relevant to elaboration of PCA results.
The negative loadings which were mostly made up of parboiled samples in the lower left quadrant
of the score plot (Figure 39a) exhibited the fermented and maize-like aroma. The fermented and
maize-like aromas were therefore positively correlated for powdered samples as observed in the
loadings plot (Figure 38b). Scores obtained in figure 38a indicated that more of the fermented
milled rice exhibited the starchy, ricey and cardboardy and these aromas are negatively correlated
with fermented and maize-like aroma for the powdery fermented rice-based products.
For flavour attributes of powdered products, the ricey, bland, sweet flavours and sweet after-taste
was presented by mostly milled rice samples particularly, the 12-hour fermented (A1) and the
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zero-hour fermented (A0) milled rice–based products (figures 40a and 40b). These attributes
negatively correlated with the rich, sour, fermented, maize/corn flavours and sour-aftertaste
observed in the negative lower quadrant of the loadings plot. Rich flavour was mostly exhibited
by the 24-hour fermented milled rice-based product (A2) while the sour, fermented flavours and
sour after-taste were observed mostly in the parboiled samples as well as the 48-hour fermented
milled rice-based products.
Re-constitution of samples with water changed the distribution of the aroma attributes in the
loading and score plots (Figures 41a and 41b). The maize-like aroma was segregated from the rest
of the attributes in the re-constituted samples (Figure 41a). Fermented and starchy aromas were
exhibited mostly by parboiled samples and negatively correlated with the ricey and cardboardy
aromas which were observed in the milled fermented re-constituted products are illustrated in
Figures 41a and 40b.
Upon reconstitution of samples with water, there was a variation established between the rich
flavour and fermented, sour, maize-like and sour-aftertaste (Figures 42a and 42b). The rich
flavour was exhibited mostly by the 24-hour fermented milled (A2) as well as the 12-hour
parboiled (B0) rice-based products (Figures 42a and 42b). The bland attribute was mostly
observed in the zero-hour fermented milled (A0) rice-based product. Ricey, sweet and sweet
after-taste was observed to be closely correlated flavour attributes of re-constituted rice-based
product and showed by the zero-hour(A0) and 12-hour(A1) fermented milled rice-based products.
The loading plot of the lyophilized samples evaluated with the electronic nose constituted the
involvement of almost all the WC sensors of the electronic nose (Figure 43a). On the left side of
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loadings plot, WS and WW sensors showed that the aroma profile of the 48-hour fermented
milled rice-based product (A3) was very different from the rest of the products. Similar sensors
were also relevant for the discrimination of the 24-hour fermented parboiled rice-based product.
The score plot demonstrated that samples were grouped along the second principal component in
the top and lower portions of the left portion of plot. There was a clear separation of the 48-hour
fermented milled rice-based sample (A3) from the other samples (Figure 43b).
Considering the score plot of the flavour attributes of samples measured with the electronic
tongue (Figure 44b), a clear difference was observed between the milled samples (A) in the
positive or upper quadrants and the parboiled samples (B) in the negative or lower quadrants
along the second Principal Component(PC2) (Figure 44a). The zero-hour (B0) fermented
parboiled rice-based  samples which were located in the positive part of the PC2, was perceived
as more astringent, rich and they also had some bitter notes in the loadings plot (Figure 44a) with
respect to milled samples (Figure 44b). The ‘umami’ taste was expressed by the zero-hour
fermented milled rice-based sample in the loadings plot (Figure 44a) and was perceived to be
different from the 12-hour, 24-hour and 48-hour fermented milled rice-based samples located in
the negative part of PC2 and which did not exhibit clear taste attributes. The parboiled samples:
(12-hour fermented) B1, (24-hour fermented) B2, (48-hour fermented) B3 located in the positive
part of PC2 were characterised by saltiness and sour flavour attributes (Figures 44a and 44b).
After-taste A and after-taste B were not clearly defined but there was evidence of their relevance
in the loadings plot (Figure 44a).
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0.500.250.00-0.25-0.50
0.0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
First Component(52.6%)
Sec
ond
Com
pon
ent
(20
.0%
)
ricey
cardboardy
fermented
starchy
maize-like
43210-1-2-3-4
2
1
0
-1
-2
-3
First Component (52.6%)
Sec
ond
Com
pon
ent
(20
.0%
)
A
B
Class
B3
B3
B3B3
B3
B3B3
B3
B2
B2
B2
B2
B2
B2B2
B2
B1
B1
B1 B1
B1
B1
B1B1
B0
B0
B0
B0
B0
B0
B0B0
A3
A3
A3
A3 A3
A3
A3
A3
A2
A2
A2
A2 A2
A2
A2
A2
A1
A1
A1
A1
A1
A1
AA1
A0
A0
A0
A0
A0
A0
A00
B3
B3
B3
B3
B3
B3B3
B3
B2
B2
B2 B2
B2
B2
2B2
B1
B1
B1
B1
B1
B1
B1
B1
B0
B0
B0
B0
B0
0B0
A3
A3
A3
3
A3
A3
3
A3
2
A2
A2 A2
A2
A2
A2
A2
A1
A1
A1
1
A1
A1
A1
A1
A0
A0
0
A0
A0
A0
A0
0
Figure 38a Loading plot of aroma attributes (powdered samples)
Figure 38b Score plot of aroma attributes (powdered samples)
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Figure 39a Loading plot of flavour attributes (powdered samples)
0.50.40.30.20.10.0-0.1-0.2-0.3-0.4
0.0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
First Component (39.6%)
Sec
ond
Com
pon
ent
(23
.2%
)
sour after-taste
sweet after-taste
ricey flavour
fermented flavour
bland
sourmaize/corn
sweet
rich
Figure 39b Score plot of flavour attributes (powdered samples)
5.02.50.0-2.5-5.0
2
1
0
-1
-2
-3
-4
-5
-6
First Component (39.6%)
Sec
ond
Com
pon
ent
(23
.2%
)
A
B
Class
B3
B3
B3
B3
B3
B3
B3
B3
B2
B2
B2
B2
B2
B2
B2B2
B1
B11B1
B1
B1
B1
B1
B0
B0
B0
B0 B0
B0
B0 B0
A3
A3 A3
A3
A3
A3
A3
A3
A2
A2
2
A2
A2
A2
A2A2
A1
A1 A1A1
A1
A1
A1A1
A0
A0
A0
A0A0
A0
A0
A0
B3
B3B3
B3
B3
B3
B3
B3
B2
2B2
B2 B2
B2B2
B1
B1
B1B1
1
B1
B1 1 B0B0
B0
B0 B0
B0
B0
B0
A3
A3 A3A3
A3
A3
A3
A3
A2
A2
A2
A2
A2
A2
A2
A2
A1
A1
A1
A1
A1
A1
A1 A1
A0
A0 0
A0
A0 A0
A0
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Figure 4.5.1.1.2a 13
0.70.60.50.40.30.20.10.0-0.1
0.75
0.50
0.25
0.00
-0.25
-0.50
First Component (34.0%)
Sec
ond
Com
pon
ent
(24
.7%
)
riceycardboardy
fermented
starchy
maize-like
3210-1-2
2
1
0
-1
-2
-3
First Component (34.0%)
Sec
ond
Co
mp
one
nt
(24
.7%
)
A
B
Class
B3
B3
B3B3
B3
B3
B3
B3
B2
B2
B2
B2 B2
B2
B2
B2
B1
B1
B1
B1
B1
B1
B1
B1
B0
0
B0
B0
B0
B0
B0
B0
A3A3
A3 A3
A3
A3
A3
A3
A2
A2
A2A2
A2
A2
A2 A2
A1
A1
A1
A1
A1
A1
A1
A1
A0
A0
A0A0
A0
A0
A0
A0
B3B3
B3
B3
B3
B3
B3
B3
B2
B2
B2
B2 B2
B2
B2
B2
B1
B1
B1B1
B1
B1
B1
B1
B0
B0
B0 B0
B0
B0
B0
B0
A3A3
A3 A3
A3
A3
A3
A2
A2
A2
A2
A2
A2
A2A2
A1
A1
A1
A1
A1
A1
A1
A1
A0
A0
A0 A0
A0
A0
A0
A0
igure 40a Loading plot of aroma attributes (re-constituted samples)
Figure 40b Score plot of aroma attributes (re-constituted samples)
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Figure 4.5.1.1.2a 14
0.50.40.30.20.10.0-0.1-0.2
0.2
0.1
0.0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
First Component (32.6%)
Sec
ond
Com
pon
ent
(18.
3%
)
sour after-taste
sweet after-taste
ricey flavour
fermented flavour
bland
sour
maize/corn
sweet
rich
Figure 4.5.1.1.2a 15
543210-1-2-3
2
1
0
-1
-2
-3
-4
-5
First Component (32.6%)
Sec
ond
Com
pon
ent
(18
.3%
)
A
B
Class
B3
B3
B3 B3
B3
B3
B3 B3 B2B2
B2
B2
B2B2
B2 B2
B1
1 B1
B1
B1
B1
B1
B1 B0
B0
B0
B0B0
B0B0
B0
A3
A3
A3
A3A3
A3
A3
A3
A2
A2
A2A2
A2
A2
A2
A2
A1
A1 A1
A1
A1
A1
A1 A1
A0
A0
A0
A0
A0
A0
0
A0
B3
B3 B3 B3
B3
B3
3 B3
B2
B2
B2
B2
B2B2
B2 B2
B1
B1 B1
B1
B1
B1
1 B1
B0
B0
B0
B0
B0
B0
B0 A3
A3 A3
A3
A3
A3A3
A3
A2
A2
A2 A2
A2
A2
A2 A2
A1
A1
A1
A1A1
A1
A1
A1
A0
0
A0
A0
A0
A0
A
A0
Figure 41a Loading plot of flavour attributes (re-constituted samples)
Figure 41b Score plot of flavour attributes (re-constituted samples)
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0.40.30.20.10.0-0.1-0.2-0.3-0.4
0.2
0.1
0.0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
First Principal Component
Sec
ond
Pri
nci
pal
Com
pon
ent
W3SW2W
W2S
W1WW1S
W5C
W6S
W3C
W5S
W1C
Figure 4.5.1.1.2a 16
86420-2-4
2
1
0
-1
-2
First Principal Component (81.6%)
Sec
ond
Prin
cipa
lCo
mp
one
nt(
13.5
%)
A
B
Class
A0
A0
A1
A1
A2
A2
A3
A3
B0
B0
B1
B1
B2
B2
B3
B3
Figure 42a Loading plot for aroma attributes of samples using the electronic nose
Figure 42b Score plot for aroma attributes of samples using the electronic nose
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Figure 4.5.1.1.2a 17
0,500,250,00-0,25-0,50
0,6
0,4
0,2
0,0
-0,2
-0,4
First Principal Component (49.0%)
Sec
ond
Prin
cipa
lCo
mpo
nen
t(2
6.8%
)
Saltiness
Richness
Umami
Aftertaste-A
Aftertaste-B
Astringency
Bitterness
Sourness
Figure 4.5.1.1.2a 18
43210-1-2-3
3
2
1
0
-1
-2
-3
First Principal Component (49.0%)
Sec
ond
Prin
cip
alC
om
pon
ent
(26
.8%
) 12
3
Replicates
B3 B2
B1
B0
A3
A2
A1
A0
B3
B2
B1
B0
A3
A2 A1
A0
B3 B2
B1
B0
A3
A2 A1
A0
Figure 43a Loading lot for flavour attributes of samples using the electronic tongue
igure 43b Score plot for flavour attributes of samples using the electronic tongue
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CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
5.1 Conclusion
Local rice contains a large percentage of brokens and hence has a low market value. Parboiling as
a pre-milling method produces rice that is nutrient dense but with harder texture, discolored grains
with a strong characteristic flavour. Size reduction and fermentation which are simple food
processing techniques were employed to transform and improve the physical, functional, and
sensory properties while adding value to local rice in Ghana.
The fermentation time as well as the parboiling treatment had varied influences on ready-to-eat
rice-based baby food products. Parboiling together with increasing fermentation time improved
the lightness of the products  Parboiling and increasing fermentation time also produced products
that were more sour with lower pH values and corresponding higher titratable or total acidity
values. Milled fermented rice-based products had higher water absorption indices but lower water
solubility indices as fermentation increased. Milled fermented rice-based samples showed higher
values for all pasting indicators: peak viscosity, breakdown, setback; except for gelatinization
temperature and holding viscosities (trough and final viscosity) which were higher for fermented
parboiled rice-based products as fermentation progressed. The pasting profiles of fermented
milled rice-based samples indicated that they would produce thinner gruels when re-constituted
with hot boiling water because of the low trough and final viscosity (hot paste stability) values.
Protein solubility increased with fermentation time until after twelve hours when it decreased
through to 48 hours fermentation time.  Solubility of milled rice proteins was higher than those in
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parboiled rice. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)
showed that most of the proteins in milled samples were hydrolyzed by the 12th hour of
fermentation while parboiled rice proteins took a longer fermentation time to hydrolyze because
of the formation of more aggregates in this sample group. Parboiled rice-based products showed
higher amount of accessible thiols than milled rice samples with increasing fermentation time.
Protein and starch digestibilities of all products were mostly influenced by fermentation time
rather than the parboiling treatment.
Sensory evaluation showed that parboiled samples were described differently in relation to the
aroma and flavour attributes perceived as being generally more sour, fermented and rich.
Powdered forms of products were generally dry and gritty in texture while re-constituted forms
were described as smooth, pasty and gritty.
5.2 Recommendation
It is recommended that further studies should be carried out to determine and classify the volatiles
responsible for the flavour and aroma notes as described in the sensory results of this study using
a Gas Chromatography-Mass Spectrophotometer (GC-MS). High-pressure liquid chromatography
(HPLC) analysis should be employed to identify the specific organic acids and sugars that
contributed to the pH and total acidity values observed in the study. Furthermore, microbiological
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studies should also be carried out to ascertain the microorganisms present at the different
fermentation periods during dough preparation and soaking time. The sorption characteristics and
shelf-life studies of the products produced in this study should also be investigated. Other local
rice varieties could also be investigated following similar processing procedures as was done in
this study.
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REFERENCES
Adams, M. R. (1990). Topical aspects of fermented foods. Trends in Food Science & Technology,
1, 140-144.
Adeniran, O., Atanda, O., Edema, M., & Oyewole, O. (2012). Characterization of lactic acid
bacteria and yeast isolates associated with traditional soaking of “ofada” rice. Journal of Food
Processing and Preservation, 36(5), 477-482.
Adu-Kwarteng, E., Ellis, W.O., Oduro, I. & Manful, J.T. (2003). Rice grain quality: a comparison
of local varieties with new varieties under study in Ghana. Food Control 14(1), 507 – 514.
Afoakwa, E. O., Sefa-Dedeh, S., & Sakyi-Dawson, E. (2004). Effects of cowpea fortification,
dehydration method and storage time on some quality characteristics of maize-based traditional
weaning foods. African Journal of Food, Agriculture, Nutrition and Development, 4(1).
Afoakwa, E. O., Adjonu, R., & Asomaning, J. (2010). Viscoelastic properties and pasting
characteristics of fermented maize: influence of the addition of malted cereals. International
journal of food science & technology, 45(2), 380-386.
Aggett, P. J., Agostoni, C., Axelsson, I., Edwards, C. A., Goulet, O., Hernell, O., ...& Rigo, J.
(2003). Non-digestible carbohydrates in the diets of infants and young children: a commentary by
the ESPGHAN Committee on Nutrition. Journal of pediatric gastroenterology and
nutrition, 36(3), 329-337.
Akeson, W. R., &Stahmann, M. A. (1964). A pepsin pancreatin digest index of protein quality
evaluation. Journal of Nutrition, 83, 257-261
Allen, L. H. (2003). B vitamins: proposed fortification levels for complementary foods for young
children. The Journal of nutrition, 133(9), 3000S-3007S.
University of Ghana http://ugspace.ug.edu.gh
117
Al-Muhtaseb, A. H., McMinn, W. A. M., & Magee, T. R. A. (2002). Moisture sorption isotherm
characteristics of food products: a review. Food and Bioproducts Processing, 80(2), 118-128.
Amagloh, F. K., Weber, J. L., Brough, L., Hardacre, A., Mutukumira, A. N., & Coad, J. (2012).
Complementary food blends and malnutrition among infants in Ghana: a review and a proposed
solution. Scientific Research and Essays, 7(9), 972-988.
Amankwah, E. A., Barimah, J., Nuamah, A. K. M., Oldham, J. H., Nnaji, C. O., & Knust, P.
(2009). Formulation of weaning food from fermented maize, rice, soybean and fishmeal. Pakistan
Journal of Nutrition, 8(11), 1747-1752.
Amissah, J.G.N., Ellis,W.O., Oduro,& J.T.Manful. 2003. Nutrient composition of bran from new
rice varieties under study in Ghana. Food Control. 14(1), 21-24.
Anderson, R. A., Conway, H. F., Pfeifer, V. F., & Griffin, E. L. (1969). Roll and extrusion-
cooking of grain sorghum grits. Cereal Science Today, 14(11), 372-376.
Angelucci, F., Asante-Poku, A., &Anaadumba, P. (2013). Analysis of incentives and
disincentives for rice in Ghana. Technical notes series. MAFAP, FAO, Rome.
Annan, N. T., Poll, L., Sefa‐Dedeh, S., Plahar, W. A., &Jakobsen, M. (2003). Volatile compounds
produced by Lactobacillus fermentum, Saccharomyces cerevisiae and Candida krusei in single
starter culture fermentations of Ghanaian maize dough. Journal of Applied Microbiology, 94(3),
462-474.
Asante, M.D, Asante B.O, Acheampong, G.K., Offei S.K., Gracen, V., Adu-Dapaah, H.&
Danquah, E.Y. (2013) Farmer and consumer preferences for rice in the Ashanti region of Ghana:
Implications for rice breeding in West Africa. Journal of Plant Breeding and Crop Science,5(12),
229-238.
University of Ghana http://ugspace.ug.edu.gh
118
Association of Official Analytical Chemists (AOAC). (2000). Official Methods of Analysis, 17th
ed. AOAC International, Gaithersburg, MD.
Assuming-Brempong S. (1998). “Profitability, ompetitiveness and Welfare effects
of Trade Liberalisation in the Rice Sub sector in Ghana ” in “Structural Adjustment and
Agriculture in West Africa” OPESRIA Book Series, Senegal pp. 276–298.
Ayamdoo, J. A., Demuyako, B., Dogbe, W., & Owusu, R. (2013). Parboiling of paddy rice, the
science and perceptions of it as practiced in northern Ghana. International Journal of Scientific
and Technology 2(4), 13-18.
Ayernor, G. S.& Hammond, T. K. (2001). Characteristics of malted rice for the production of
sugar syrup. Journal of the Ghana Science Association, 3(3), 91-99.
Baldwin, E. A., Bai, J., Plotto, A., & Dea, S. (2011). Electronic noses and tongues: Applications
for the food and pharmaceutical industries. Sensors, 11(5), 4744-4766.
Barbiroli, A., Bonomi, F., Casiraghi, M. C., Iametti, S., Pagani, M. A., & Marti, A. (2013).
Process conditions affect starch structure and its interactions with proteins in rice
pasta. Carbohydrate polymers, 92(2), 1865-1872.
Barnett, D. (1999). Probabilities and possibilities: on-line sensors for food processing. Tastes and
Aromas, The Chemical Senses in Science and Industry.
Baxter, G., Blanchard, C., & Zhao, J. (2004). Effects of prolamin on the textural and pasting
properties of rice flour and starch. Journal of cereal Science, 40(3), 205-211.
Beaumont, M. (2002). Flavouring composition prepared by fermentation with Bacillus spp.
International journal of food microbiology, 75(3), 189-196.
University of Ghana http://ugspace.ug.edu.gh
119
Bernal, M. J., Periago, M. J., &Ros, G. (2002). Effects of processing on dextrin, total starch,
dietary fiber and starch digestibility in infant cereals. Journal of food science-Chicago-, 67(3),
1249-1254.
Bhattacharya, P., Gosh,U., Chowdhuri, U. Roy, Chattopadhyay, P., &Gangopadhyay, H. (2004).
Effects of different treatments on physico-chemical properties of rice starch. Journal of Science
and Industrial Research 63(1), 826-829.
Birch, G. (1997). Carbohydrate chemistry for food scientists: RL Whistler and JN Bemiller.
Eagan Press, St. Paul, MN 1997. ISBN 0-913250-92-9. 240 pp. 117–151.
Blandino, A., Al-Aseeri, M. E., Pandiella, S. S., Cantero, D., & Webb, C. (2003). Cereal-based
fermented foods and beverages. Food research international, 36(6), 527-
543.http://dx.doi.org/10.1016/S0963-9969(03)00009-7
Boboye, B. E., &Daramola, I. O. (2011). Regulation of glucose and protein syntheses by
Micrococcus luteus during the fermentation of a Nigerian rice, Oryza sativa variety" Igbimo".
Advances in Bioscience and Biotechnology, 2(4), 244-247.
http://dx.doi.org/10.4236/abb.2011.24035
Boboye, B., &Terwase, D. E. (2004). Bacteria and nutritional changes associated with natural
fermentation of a Nigerian indigenous rice (Oryza sativa “Igbimo”). Oriental Journal of
Chemistry, 20(2), 235-237.
Bradford, M. M. (1976). A rapid and sensitive method for the quantitation of microgram
quantities of protein utilizing the principle of protein-dye binding. Analytical biochemistry,72(1-
2),248-254.
University of Ghana http://ugspace.ug.edu.gh
120
Brown, K. H. (1997). Complementary feeding in developing countries: factors affecting energy
intake. Proceedings of the Nutrition Society, 56(1A), 139-148.
Buléon, A., Colonna, P., Planchot, V., & Ball, S. (1998). Starch granules: structure and
biosynthesis. International journal of biological macromolecules, 23(2), 85-112.
Cabrera-Chávez, F., de la Barca, A. M. C., Islas-Rubio, A. R., Marti, A., Marengo, M., Pagani,
M. A., ... &Iametti, S. (2012). Molecular rearrangements in extrusion processes for the production
of amaranth-enriched, gluten-free rice pasta. LWT-Food Science and Technology, 47(2), 421-426.
Cao, X., Wen, H., Li, C., &Gu, Z. (2009). Differences in functional properties and biochemical
characteristics of congenetic rice proteins. Journal of cereal science, 50(2), 184-189.
Center, A. R. (2010). New breeding directions at AfricaRice: Beyond NERICA. Africa Rice
Center, Cotonou, Benin.
Chakravarthi S, Kapoor R. 2003. Development of a nutritious low viscosity weaning mix using
natural ingredients and microbial amylases. International  Journal  Food Science Technology
54(5), 341 – 347.
Champagne, E. T., Bett, K. L., Vinyard, B. T., McClung, A. M., Barton, F. E., Moldenhauer,
K.,Moldenhauer, K., Linscombe, S.& McKenzie, K. (1999). Correlation between cooked rice
texture and rapid viscoanalyser measurements. Cereal Chemistry, 76(5), 764-771.
Charunuch, C., Limsangouan, N., Prasert, W., &Wongkrajang, K. (2014). Optimization of
extrusion conditions for ready-to-eat breakfast cereal enhanced with defatted rice bran.
International Food research journal, 21(2), 713-722.
University of Ghana http://ugspace.ug.edu.gh
121
Chiang, P. Y. &Yeh, A. I. (2002). Effect of soaking on wet-milling of rice. Journal of Cereal
Science, 35(1), 85-94.
Chrastil, J. (1992). Correlations between the physicochemical and functional properties of
rice. Journal of Agricultural and Food Chemistry, 40(9), 1683-1686.
Chung, H. J., Liu, Q., Lee, L., & Wei, D. (2011). Relationship between the structure,
physicochemical properties and in vitro digestibility of rice starches with different amylose
contents. Food Hydrocolloids, 25(5), 968-975.
Cooper, R. G. (1988). The new product process: a decision guide for management. Journal of
Marketing Management, 3(3), 238-255.
Copeland, L., Blazek, J., Salman, H., & Tang, M. C. (2009). Form and functionality of starch.
Food Hydrocolloids, 23(6), 1527-1534.
Corrêa, P. C., Da Silva, F. S., Jaren, C., Afonso, P. C., & Arana, I. (2007). Physical and
mechanical properties in rice processing. Journal of food engineering, 79(1), 137-142.
Coalition for African Rice Development (CARD) (2010). Mapping of Poverty Reduction Strategy
Papers (PRSPs), Sector Strategies and Policies related to rice development in Ghana
CRI (Crops Research Institute) and MOFA (Ministry of Food and Agriculture). 2005. Steps to
Good Rice Production in the Lowlands, rev. ed. Kumasi, Ghana: CRI and MOFA, Inland Valleys
Rice Development Project.
Daud, W. R. B. W., & Armstrong, W. D. (1987). Pilot plant study of the drum dryer. Drying
Technology, 87, 101-108.
University of Ghana http://ugspace.ug.edu.gh
122
Deepa, G., Singh, V., & Naidu, K. A. (2010). A comparative study on starch digestibility,
glycemic index and resistant starch of pigmented (‘Njavara’and ‘Jyothi’) and a non-pigmented
(‘IR 64’) rice varieties. Journal of food science and technology, 47(6), 644-649.
DeMan, J.M. (1999). Principles of Food Chemistry (3rd edition) Aspen Publishers, Maryland,
229–262.
De Meyer, A., & Van Hooland, B. (1990). The contribution of manufacturing to shortening
design cycle times. R&D Management, 20(3), 229-239.
Den Besten, P.J. (1998). Cytochrome P450 monooxygenase system in echinoderms.
Comparative Biochemistry & Physiology, 121(1), 139–146.
Deshpande, S. S. (2000). Fermented grain legumes, seeds and nuts: a global perspective (Vol.
142). Food & Agriculture Org..
Dewey, K. G. (2003). Nutrient composition of fortified complementary foods: should age-specific
micronutrient content and ration sizes be recommended? The Journal of nutrition, 133(9), 2950S-
2952S.
Diako, C., Manful, J. T., Johnson, P. N. T., Sakyi-Dawson, E., Bediako-Amoa, B., & Saalia, F. K.
(2010). Physicochemical characterization of four commercial rice varieties in Ghana. Advance
Journal of Food Science and Technology, 3(3), 196-202.
Ding, Q. B., Ainsworth, P., Tucker, G., & Marson, H. (2005). The effect of extrusion conditions
on the physicochemical properties and sensory characteristics of rice-based expanded snacks.
Journal of Food Engineering, 66(3), 283-289.
University of Ghana http://ugspace.ug.edu.gh
123
Djedatin, G., Ndjiondjop, M.N., Mathieu, T., Cruz, M.V., Sanni, A., Ghesquière, A.,& Verdier,
V. (2011) Evaluation of African cultivated rice Oryza glaberrima for resistance to bacterial
blight. Plant Disease 95(4), 441–447.
Dijksterhuis, G. B., & Byrne, D. V. (2005). Does the mind reflect the mouth? Sensory profiling
and the future. Critical reviews in food science and nutrition, 45(7-8), 527-534.
Dreher, M. L., Dreher, C. J., Berry, J. W., & Fleming, S. E. (1984). Starch digestibility of foods: a
nutritional perspective. Critical Reviews in Food Science & Nutrition, 20(1), 47-71.
Duhan, A., Khetarpaul, N., & Bishnoi, S. (2002). Content of phytic acid and HCl-extractability of
calcium, phosphorus and iron as affected by various domestic processing and cooking methods.
Food Chemistry, 78(1), 9-14.
Egounlety, M., Aworh, O.C., Akingbala, J.O., Houben,  J.H.,& Nago, M.C. (2002). Nutritional
and sensory evaluation of tempe-fortified maize-based weaning foods. International Journal
Food Science Nutrition 53(1), 15 – 27.
El, S. N., & Kavas, A. (1997). Available lysine in dried milk after processing. International
journal of food sciences and nutrition, 48(2), 109-111.
El-Dash, A. A., Gonzales, R., &Ciol, M. (1983). Response surface methodology in the control of
thermoplastic extrusion of starch. Journal of Food Engineering, 2(2), 129-152.
Elkhalifa, A. E. O., Bernhardt, R., Bonomi, F., Iametti, S., Pagani, M. A., &Zardi, M. (2006).
Fermentation modifies protein/protein and protein/starch interactions in sorghum
dough. European Food Research and Technology,222(5-6), 559-564.
Englyst, H. N., Kingman, S., &Cummings, J. (1992). Classification and measurement of
University of Ghana http://ugspace.ug.edu.gh
124
nutritionally important starch fractions. Eur. J. Clin. Nutr. 46:33-50.
Escuder-Gilabert, L., & Peris, M. (2010). Review: Highlights in recent applications of electronic
tongues in food analysis. AnalyticaChimicaActa, 665(1), 15-25.
Falade, K. O., Semon, M., Fadairo, O.S., Oladunjoye, A. O.,& Orou, K. K. (2014). Functional
and physico-chemical properties of flours and starches of African rice cultivars. Food
Hydrocolloids, 39(1), 41-50.
Falagas, S. (1985). During agricultural products (pp. 80-83). Athens: Elkepa (in Greek).
Fennema, O. R. (1996). Food chemistry. Food Science and Technology-Marcel Dekker, Inc.
Taylor & Francis.
Fernández-Artigas, P., Guerra-Hernandez, E., & Garcı́a-Villanova, B. (2001). Changes in sugar
profile during infant cereal manufacture. Food chemistry, 74(4), 499-505.
Gayin, J., Manful, J. T., Johnson, P-N.T. (2009). Rheological and sensory properties of rice
varieties from improvement programmes in Ghana. International Food Research Journal 16(1),
167-174.
Graham, R., Senadhira, D., Beebe, S., Iglesias, C., & Monasterio, I. (1999). Breeding for
micronutrient density in edible portions of staple food crops: conventional approaches. Field
Crops Research, 60(1), 57-80.
Hahn, D. H., Faubion, J. M., Ring, S. H., Doherty, C. A., & Rooney, L. W. (1982).
Semiautomated in vitro analysis of sorghum protein availability via pronase hydrolysis. Cereal
chem, 59(2), l32-l36.
University of Ghana http://ugspace.ug.edu.gh
125
Hamaker, B. R., & Griffin, V. K. (1993). Effect of disulfide bond-containing protein on rice
starch gelatinization and pasting. Cereal Chemistry,70, 377–380.
Han, X. Z., &Hamaker, B. R. (2001). Amylopectin fine structure and rice starch paste breakdown.
Journal of Cereal Science, 34(3), 279-284.
Hamad, A. M., & Fields, M. L. (1979). Evaluation of the protein quality and available lysine of
germinated and fermented cereals. Journal of Food Science, 44(2), 456-459.
Haugen, J. E. (2001). Electronic noses in food analysis. In Headspace analysis of foods and
flavors (pp. 43-57). Springer US.
Hayes. R., Wheelwright. S. G. & Clark, K. B. (1988). Dynamic Manufacturing. New York: The
Free Press.
Hoover, R. (2001). Composition, molecular structure, and physicochemical properties of tuber
and root starches: a review. Carbohydrate polymers, 45(3), 253-267.
Hotz, Rosalind S. Gibson, Lara Temple, C. (2001). A home-based method to reduce phytate
content and increase zinc bioavailability in maize-based complementary diets. International
journal of food sciences and nutrition, 52(2), 133-142.
Hsu, S., Lu, S., & Huang, C. (2000). Viscoelastic changes of rice starch suspensions during
gelatinization. Journal of Food Science, 65(2), 215-220.
Hu, P., Zhao, H., Duan, Z., Linlin, Z., & Wu, D. (2004). Starch digestibility and the estimated
glycemic score of different types of rice differing in amylose contents. Journal of Cereal Science,
40(3), 231-237.
University of Ghana http://ugspace.ug.edu.gh
126
Iametti, S., Bonomi, F., Pagani, M. A., Zardi, M., Cecchini, C., &D'Egidio, M. G. (2006).
Properties of the protein and carbohydrate fractions in immature wheat kernels. Journal of
agricultural and food chemistry, 54(26), 10239-10244.
Ibanez, A.A., Wood, D.F, Yokoyama,W.H., Park,I.M., Tinoco, M.A., Hudson, C.A. (2007).
Viscoelastic properties of waxy and nonwaxy rice flours, their fat and protein-free starch, and the
microstructure of their cooked kernels. Journal of Agriculture and Food Chemistry, 55 (16)
(2007), 6761–6771.
Ilo, S., & Berghofer, E. (1999). Kinetics of colour changes during extrusion cooking of maize
grits. Journal of Food Engineering, 39(1), 73-80.
IRRI (2009). Quality Rice seed. Rice Knowledge bank International Rice Research
Institute (IRRI).
Jane, J. L., & Robyt, J. F. (1984). Structure studies of amylose-V complexes and retro-graded
amylose by action of alpha amylases, and a new method for preparing amylodextrins.
Carbohydrate research, 132(1), 105-118.
Jenkins, D. J. A., Ghafari, H., Wolever, T. M. S., Taylor, R. H., Jenkins, A. L., Barker, H. M., ...
& Bowling, A. C. (1982). Relationship between rate of digestion of foods and post-prandial
glycaemia. Diabetologia, 22(6), 450-455.
Juliano, B. O. (1985). Factors affecting nutritional properties of rice protein. Transactions of the
National Academy of Science and Technology (Philippines).
Juliano, B.O. (1992) . Structure, chemistry and function of the rice grain and its fraction.
Cereal Foods World. 41(1), 827-832.
University of Ghana http://ugspace.ug.edu.gh
127
Juliano, B.O. (1998). Varietal impact on rice quality. Cereal Foods World 43(1), 207-222.
Juliano, B.O. & Goddard, M.Y. (1986). Cause of varietal difference in insulin and glucose
response to ingested rice. Plant Foods in Human Nutrition, 36 (1),35–41.
Juliano, B. O., Perez, C. M., Blakeney, A. B., Castillo, D. T., Kongseree, N.,Laignelet, B., Lapis,
E. T., Murty, V. V. S., Paule, C. M., & Webb, B. D.(1981). International cooperative testing on
the amylose content ofmilled rice. Starch-Stärke, 33(5), 157–162.
Kabeir, B. M., Shuhaimi, M., Muhammad, K., Abd-Aziz, S., & Yazid, A. M. (2004). A nutritious
medida (sudanese cereal thin porridge) prepared by fermenting malted brown rice flour with
Bifidobacterium longum BB 536. Malaysian journal of nutrition, 10(2), 183-193.
Kalui, C., Mathara, J., Kutima, P., Kiiyukia, C., & Wongo, L. (2009). Functional characteristics
of Lactobacillus plantarum and Lactobacillus rhamnosus from ikii, a Kenyan traditional
fermented maize porridge. African Journal of Biotechnology, 8(18), 4363-4373.
Kapil, U. (2000). Progress made in elimination of IDD and possible impact of lifting ban on sale
of non-iodized salt. J AcadHosp Admin, 12, 33-41.
Kapsalis, J. G. (1987). Influences of hysteresis and temperature on moisture sorption isotherms.
Water activity: theory and applications to food, 173-213.
Karovičová, Z. K. J. (2007). Fermentation of cereals for specific purpose. Journal of Food and
Nutrition Research, 46(2), 51-57.
Keatkrai, J.,& Jirapakkul, W. (2010). Volatile profile of khanomjeen, Thai fermented rice
noodles, and the changes during the fermentation process. ScienceAsia, 36(2010), 46-51.
University of Ghana http://ugspace.ug.edu.gh
128
Kirby, A. R., Ollett, A. L., Parker, R., & Smith, A. C. (1988). An experimental study of screw
configuration effects in the twin-screw extrusion-cooking of maize grits. Journal of Food
Engineering, 8(4), 247-272.
Kitson, J. A., & MacGregor, D. R. (1982). Technical note: Drying fruit purées on an improved
pilot plant drum‐drier. International Journal of Food Science & Technology, 17(2), 285-288.
Komatsuzaki, N., Tsukahara, K., Toyoshima, H., Suzuki, T., Shimizu, N., & Kimura, T. (2007).
Effect of soaking and gaseous treatment on GABA content in germinated brown rice. Journal of
Food Engineering, 78(2), 556-560.
Kranjac-Berisavljevic, G., Blench, R.M.& Chapman, R.(2003). Rice production and livelihoods
in Ghana. Multi-agency partnerships for technicalchange in West African agriculture. Accessed
July 2011, available athttp://www.odi.org.uk/resources/docs/3990.pdf
Krishnan, S., & Dayanandan, P. (2003). Structural and histochemical studies on grain-filling in
the caryopsis of rice (Oryza sativa L.). Journal of biosciences, 28(4), 455-469.
Kyritsi, A., Tzia, C., & Karathanos, V. T. (2011). Vitamin fortified rice grain using spraying and
soaking methods. LWT-Food Science and Technology, 44(1), 312-320.
Lai, V. M. F., Lu, S., &Lii, C. Y. (2000). Molecular characteristics influencing retrogradation
kinetics of rice amylopectins. Cereal Chemistry, 77(3), 272-278.
Lartey, A., Manu, A., Brown, K. H., Peerson, J. M., & Dewey, K. G. (1999). A randomized,
community-based trial of the effects of improved, centrally processed complementary foods on
growth and micronutrient status of Ghanaian infants from 6 to 12 mo of age. The American
journal of clinical nutrition, 70(3), 391-404.
University of Ghana http://ugspace.ug.edu.gh
129
Lawal, O. S., Lapasin, R., Bellich, B., Olayiwola, T. O., Cesàro, A., &Yoshimura, M. (2011).
Rheology and functional properties of starches isolated from five improved rice varieties from
West Africa. Food Hydrocolloids, 25(1), 1785-1792.
Li, J., Xiao, J., Grandillo, S., Jiang, L., Wan, Y., Deng, Q., Yuan, L., and McCouch, S.R. (2004).
QTL detection for rice grain quality traits using an interspecific backcross population derived
from cultivated Asian (O. sativa L.) and African (O. glaberrimaS.) rice. Genome 47(1), 697-704.
Lii, C. Y., & Chang, Y. H. (1991). Study of starch in Taiwan. Food Reviews International, 7(2),
185-203.
Linares, O. F. (2002). African rice (Oryzaglaberrima): history and future potential. Proceedings of
the National Academy of Sciences, 99(25), 16360-16365.
Lönner, C., & Preve-Akesson, K. (1989). Effects of lactic acid bacteria on the properties of sour
dough bread. Food Microbiology, 6(1), 19-35.
Lu, Z. H., Li, L. T., Cao, W., Li, Z. G., & Tatsumi, E. (2003). Influence of natural fermentation
on physico‐chemical characteristics of rice noodles. International journal of food science &
technology, 38(5), 505-510.
Lutter, C. K., & Rivera, J. A. (2003). Nutritional status of infants and young children and
characteristics of their diets. The Journal of nutrition, 133(9), 2941S-2949S.
Lyon, B. G., Champagne, E. T., Vinyard, B. T., & Windham, W. R. (2000). Sensory and
instrumental relationships of texture of cooked rice from selected cultivars and postharvest
handling practices. Cereal Chemistry, 77(1), 64-69.
University of Ghana http://ugspace.ug.edu.gh
130
Makowska, A., Mildner-Szkudlarz, S., & Obuchowski, W. (2013). Effect of brewer’s spent grain
addition on properties of corn extrudates with an increased dietary fibre content. Polish Journal of
Food and Nutrition Sciences, 63(1), 19-23.
Mariotti, M., Iametti, S., Cappa, C., Rasmussen, P., & Lucisano, M. (2011). Characterisation of
gluten-free pasta through conventional and innovative methods: evaluation of the uncooked
products. Journal of cereal science, 53(3), 319-327.
Martin,M.& Fitzgerald, M.A. (2002). Proteins in Rice Grains Influence Cooking Properties!
Journal of Cereal Science36(1), 285-294.
Mattissek, R., Schnepel, M. F., & Steiner, G. (1992).Lebensmittelanalytik, Grundzüge. Methoden.
Anwendungen. Zweite, korrigierteAuflage.
Mensah, P. P., Tomkins, A. M., Drasar, B. S., & Harrison, T. J. (1990). Fermentation of cereals
for reduction of bacterial contamination of weaning foods in Ghana. The Lancet, 336(8708), 140-
143.
Mensah, P., Drasar, B. S., Harrison, T. J., & Tomkins, A. M. (1991). Fermented cereal gruels:
towards a solution of the weanlings dilemma. Food and Nutrition Bulletin, 13(1), 50-7.
Meuser, F., GimmLer, N., & Van Lengerich, B. (1992). A system analytical approach to
extrusion. Food extrusion science and technology, 619-630.
Miles, M. J., Morris, V. J., Orford, P. D., & Ring, S. G. (1985). The roles of amylose and
amylopectin in the gelation and retrogradation of starch. Carbohydrate research, 135(2), 271-281.
University of Ghana http://ugspace.ug.edu.gh
131
Mine, Y. (1997).Effect of dry heat and mild alkaline treatment on functional properties of egg
white proteins. Journal of Agricultural and Food Chemistry, 45(8), 2924-2928.
Ministry of Food and Agriculture (2010). Agriculture in Ghana: Facts and Figures 2010.
Statistics, Research and Information Directorate, MOFA, Accra, Ghana.
Mir, J. A., Srikaeo, K., &García, J. (2013). Effects of amylose and resistant starch on starch
digestibility of rice flours and starches. International Food Research Journal, 20(3).
Mok, C.K. (1992). Lactic acid fermentation of rice and its quality improvement strategy. In:
UNIDO International Workshop On Lactic Acid Fermentation of Non-dairy Food and Beverages
References Proceedings, Korea Food Research Institute, Seoul, Korea. pp. 58–80.
Mouquet, C., Salvignol, B., Van Hoan, N., Monvois, J., & Trèche, S. (2003). Ability of a “very
low-cost extruder” to produce instant infant flours at a small scale in Vietnam. Food Chemistry,
82(2), 249-255.
Moursi, M., Mbemba, F., & Trèche, S. (2003). Does the consumption of amylase-containing
gruels impact on the energy intake and growth of Congolese infants?. Public Health Nutrition,
6(03), 249-257.
Moskowitz, H. R. (1995). Food quality: conceptual and sensory aspects. Food Quality and
Preference, 6(3), 157-162.
Mugula, J. K., Narvhus, J. A., & Sørhaug, T. (2003). Use of starter cultures of lactic acid bacteria
and yeasts in the preparation of togwa, a Tanzanian fermented food. International journal of food
microbiology, 83(3), 307-318.
University of Ghana http://ugspace.ug.edu.gh
132
Muhimbula, H. S., Issa-Zacharia, A., & Kinabo, J. (2011). Formulation and sensory evaluation of
complementary foods from local, cheap and readily available cereals and legumes in Iringa,
Tanzania. African Journal of Food Science, 5(1), 26-31.
Mujoo, R., & Ali, S. Z. (1998). Susceptibility of Starch to in vitro Enzyme Hydrolysis in Rice,
Rice Flakes and Intermediary Products. LWT-Food Science and Technology, 31(2), 114-121.
Nagai, T., Staatz, J. M., Bernsten, R. H., Sakyi-Dawson, E. O., &Annor, G. A. (2009). Locally
processed roasted-maize-based weaning foods fortified with legumes: factors affecting their
availability and competitiveness in Accra, Ghana. African Journal of Food, Agriculture, Nutrition
and Development, 9(9).
Nagaraju, V. D., &Manohar, B. (2000). Rheology and particle size changes during Idli
fermentation. Journal of Food Engineering, 43(3), 167-171.
Nehete, J. Y., Bhambar, R. S., Narkhede, M. R., & Gawali, S. R. (2013).Natural proteins:Sources,
isolation, characterization and applications.Pharmacognosy reviews, 7(14), 107.
Newton, J., Wang, Y. J., & Mauromoustakos, A. (2011). Effects of cultivar and processing
condition on physicochemical properties and starch fractions in parboiled rice. Cereal chemistry,
88(4), 414-420.
Nicolau, A., Georgescu, L., & Bolocan, A. (2011). Impact of bio-processing on rice. The Annals
of the University of Dunarea de Jos of Galati. Fascicle VI. Food Technology, 35(1), 19.
Nnam, N.M. (1999). Chemical evaluation of multimixes formulatedfrom some local staples for
use as complementary foods in Nigeria. Plant Foods Human Nutrition 55(1), 255 – 263.
University of Ghana http://ugspace.ug.edu.gh
133
Noosuk, P., Hill, S. E., Farhat, I. A., Mitchell, J. R., & Pradipasena, P. (2005). Relationship
between viscoelastic properties and starch structure in rice from Thailand. Starch‐Stärke, 57(12),
587-598.
Nout, M. J. R. (1993). Processed weaning foods for tropical climates. International journal of
food sciences and nutrition, 43(4), 213-221.
Obesity, W. H. O. (2000). Preventing and managing the global epidemic. Report of a WHO
Consultation. WHO technical report series, 894, 1-253.
Odumodu, C. U. (2007). Optimum fermentation period for micronutrients content of cereal based
complementary food. Pakistan Journal of Nutrition, 6(6), 518-523.
Okadome, H., Kurihara, M., Kusuda, O., Toyoshima, H., Kim, J. I., Shimotsubo, K., Matsuda, T.
& Ohtsubo, K. I. (1999). Multiple measurements of physical properties of cooked rice grains with
different nitrogenous fertilizers. Japanese Journal of Crop Science, 68, 211-216.
Oko, A. O., Ubi, B. E., Efisue, A. A., & Dambaba, N. (2012). Comparative analysis of the
chemical nutrient composition of selected local and newly introduced rice varieties grown in
Ebonyi State of Nigeria. International Journal of Agriculture and Forestry, 2(2), 16-23.
http://dx.doi.org/10.5923/j.ijaf.20120202.04
Oko A. O.,  Ubi, B.E & Dambaba, N. (2012). Rice cooking quality andphysico-
chemicalcharacteristics: a comparative analysis of selected local and newly introduced rice
varieties in ebonyi state, nigeria.Food and Public Health, 2(1),43-49.
Ong, M. H.,&Blanshard, J. M. V. (1995). Texture determinants in cooked, parboiled rice. I: Rice
starch amylose and the fine structure of amylopectin.Journal of Cereal Science, 21(3), 251-260.
University of Ghana http://ugspace.ug.edu.gh
134
Onyango, C., Henle,T., Ziems,A., Hofmann, T. & Bley, T.(2004). Effect of extrusion variables on
fermented maize–finger millet blend in the production of ‘uji’. Lebensm.-Wiss. u.-Technol.
37,409–415.
Osarertin, A. T. E. & Abosede, C. O. (2008). Effect of cooking and soaking on physical, nutrient
composition and sensory evaluation of indigenous and foreign rice varieties in Nigeria. Nutrition
& Food Science, 38(1), 15-21.
Osei-Asare, Y. (2010). Mapping of Poverty Reduction Strategies and Policies Related to Rice
Development in Ghana. Nairobi, Kenya: Coalition for African Rice Development (CARD).
Overseas Development Institute (ODI) (2003). Multi-Agency Partnership for Technical Change in
West African Agriculture: Rice production and Livelihood in Ghana.
Owino, V.O., Kasonka, L.M. , Sinkala, M.M., Wells, J.K., Eaton,S., Darch, T. Coward, A,
Tomkins, A.M.& Filteau, S.M. (2007). Fortified complementary food increases growth and
hemoglobin independently of α-amylase treatment, without reducing breastmilk intake of 9-month
old Zambian infants. American Journal of Clinical Nutrition, 86 (1),1094–1103
Oyarekua, M. A. (2011). Evaluation of the nutritional and microbiological status of co-fermented
cereals/cowpea ‘OGI’. Agriculture and Biology Journal of North America, 2(1), 61-73.
Oyewole, O. B. (1997). Lactic fermented foods in Africa and their benefits. Food control, 8(5),
289-297.
Peris, M., & Escuder-Gilabert, L. (2009). A 21st century technique for food control: Electronic
noses. Analytica chimica acta, 638(1), 1-15.
University of Ghana http://ugspace.ug.edu.gh
135
Perlas, L. A., & Gibson, R. S. (2002). Use of soaking to enhance the bioavailability of iron and
zinc from rice‐based complementary foods used in the Philippines. Journal of the Science of Food
and Agriculture, 82(10), 1115-1121.
Petitot, M., Brossard, C., Barron, C., Larré, C., Morel, M. H., &Micard, V. (2009). Modification
of pasta structure induced by high drying temperatures. Effects on the in vitro digestibility of
protein and starch fractions and the potential allergenicity of protein hydrolysates. Food
Chemistry, 116(2), 401-412.
Ramı́rez-Jiménez, A., Guerra-Hernández, E., & Garcı́a-Villanova, B. (2003). Evolution of non-
enzymatic browning during storage of infant rice cereal. Food chemistry, 83(2), 219-225.
Ratnayake, W. S., & Jackson, D. S. (2008). Thermal behavior of resistant starches RS 2, RS 3,
and RS 4. Journal of food science, 73(5), C356-C366.
Reh,C., Bhat, S.N.,& Berrut, S. (2004). Journal of food chemistry 86(1), 457-464.
Roberts, C. K., & Liu, S. (2009). Effects of glycemic load on metabolic health and type 2 diabetes
mellitus. Journal of diabetes science and technology, 3(4), 697-704.
Rosado, J. L. (2003). Zinc and copper: proposed fortification levels and recommended zinc
compounds. The Journal of nutrition, 133(9), 2985S-2989S.
Rosenthal, A., & Sgarbieri, V. C. (1992). Nutritional evaluation of a fresh sweet corn drum drying
process. Drying, 92, 1419-1425.
Rowland, M. G. (1986). The weanling's dilemma: are we making
progress?ActaPaediatrica, 75(s323), 33-42.
University of Ghana http://ugspace.ug.edu.gh
136
Saalia, F.K., Ankamah, S., Otubuah, B., Barfi, N.K. &Tano-Debrah, K. (2012). Development and
characterization of low viscosity porridge (koko) flour by co-fermenting with millet
malt.Scientific reports 1(12), 1-7.
Sanders, T. A. B., & Manning, J. (1992). The growth and development of vegan children. Journal
of Human Nutrition and Dietetics, 5(1), 11-21.
Sandstedt, R. M., & Abbot, R. C. (1961). A small water-jacketed bowl for the amylograph.
Cereal Science Today, 6, 312.
Sandhu, K. S., & Singh, N. (2007). Some properties of corn starches II: Physicochemical,
gelatinization, retrogradation, pasting and gel textural properties. Food Chemistry, 101(4), 1499-
1507.
Sanni, A. I., Morlon-Guyot, J., &Guyot, J. P. (2002). New efficient amylase-producing strains of
Lactobacillus plantarum and L. fermentum isolated from different Nigerian traditional fermented
foods. International journal of food microbiology, 72(1), 53-62.
Santos, Karina FreireD'eçaNogueira, Silveira, Ricardo Diógenes Dias, Martin-Didonet, Claudia
Cristina Garcia, &Brondani, Claudio. (2013).Storage protein profile and amino acid content in
wild rice Oryzaglumaepatula. PesquisaAgropecuáriaBrasileira, 48(1), 66-72.
https://dx.doi.org/10.1590/S0100-204X2013000100009
Sasaki, T., Kohyama, K., Suzuki, Y., Okamoto, K., Noel, T. R., & Ring, S. G. (2009).
Physicochemical characteristics of waxy rice starch influencing the in vitro digestibility of a
starch gel. Food Chemistry, 116(1), 137-142.
Sefa-Dedeh, S.&Mensah, E. O. (1991). Traditional food-processing technology and high-protein
food production. Food Nutr Bull, 13(1), 43-9.
University of Ghana http://ugspace.ug.edu.gh
137
Schilling, M. A., & Hill, C. W. (1998). Managing the new product development process: Strategic
imperatives. The Academy of Management Executive, 12(3), 67-81.
Sié, M., Sanni, K., Futakuchi, K., Manneh, B., Mandé, S., Vodouhé, R., Dogbe, S., Dramé, K.N.,
Ogunbayo, A., Ndjiondjop, M.N.&Traoré, K. (2012). Towards a rational use of African rice
(OryzaglaberrimaSteud.) for breeding in Sub-Saharan Africa. Genes, genomes and genomics,
6(1), 1-7.
Sievert, D., &Wuesch, P. (1993). Amylose chain association based on differential scanning
calorimetry. Journal of food science, 58(6), 1332-1335.
Sindhu, S. C., & Khetarpaul, N. (2001). Probiotic fermentation of indigenous food mixture: effect
on antinutrients and digestibility of starch and protein. Journal of Food Composition and
Analysis, 14(6), 601-609.
Singh, H., & Soni, S. K. (2001). Production of starch-gel digesting amyloglucosidase by
Aspergillus oryzae HS-3 in solid state fermentation. Process Biochemistry, 37(5), 453-459.
Singh, N., Nakaura, Y., Inouchi, N., & Nishinari, K. (2007). Fine structure, thermal and
viscoelastic properties of starches separated from Indica rice cultivars. Starch‐Stärke, 59(1), 10-
20.
Singh, J., Dartois, A., & Kaur, L. (2010). Starch digestibility in food matrix: a review. Trends in
Food Science & Technology, 21(4), 168-180.
Sodhi, S., N., &Singh, N. (2003). Morphological, thermal and rheological properties of starches
separated from rice cultivars grown in India. Journal of Food Chemistry, 80(1), 9-108.
University of Ghana http://ugspace.ug.edu.gh
138
Soni, S. K., Sandhu, D. K., &Vilkhu, K. S. (1985). Studies on dosa—an indigenous Indian
fermented food: some biochemical changes accompanying fermentation. Food Microbiology,
2(3), 175-181.
SRID (2005). Agriculture in Ghana 2005, Statistics, Research and Information Directorate.
Steinkraus, K. H. (1996). Classification of fermented foods: worldwide review of household
fermentation techniques. Food Control, 8(5), 311-317.
Stone, H. & Sidel, J.L. (2004). Sensory Evaluation Pratices.3.Ed. London: Elsevier Academic
Press, 2004. 377 P. (Food Science and Technology. International Series).
Stone, H., Sidel, J., Oliver, S., Woolsey, A., &Singleton, R.C. (1974) Sensory evaluation by
quantitative descriptive analysis. Food technology 28(1), 24–34
Stone, H., Sidel, J.L. (2007). Sensory research and consumer-led food product development. In:
MacFie H (ed) Consumer-led food product development. CRC Press, Boca Raton, FL, pp 307–
320.
Structure of the Rice Grain (2015). Retrieved from www.riceweb.org/planthtm. Accessed on 27th
January, 2015 at 12:00pm.
Sulieman, M. A., Hassan, A. B., Osman, G. A., El Tyeb, M. M., El Khalil, E. A., El Tinay, A. H.,
& Babiker, E. E. (2008). Changes in total protein digestibility, fractions content and structure
during cooking of lentil cultivars. Pakistan Journal of Nutrition, 7(6), 801-805.
Sveinsdottir, K., Martinsdottir, E., Thorsdottir, F., Schelvis, R., Kole, A., & Thorsdottir, I. (2010).
Evaluation of farmed cod products by a trained sensory panel and consumers in different test
settings. Journal of Sensory Studies, 25(2), 280-293.
University of Ghana http://ugspace.ug.edu.gh
139
Takeuchi, H., & Nonaka, I. (1986). The new product development game. Harvard business
review, 64(1), 137-146.
Tang, M. C., & Copeland, L. (2007). Analysis of complexes between lipids and wheat starch.
Carbohydrate Polymers, 67(1), 80-85.
Tan, Y., & Corke, H. (2002). Factor analysis of physicochemical properties of 63 rice varieties.
Journal of Food and Agricultural Science 82(1), 745-752.
Tomlins, K. I., Manful, J. T., Larwer, P., & Hammond, L. (2005). Urban consumer preferences
and sensory evaluation of locally produced and imported rice in West Africa. Food Quality and
Preference, 16(1), 79-89.
Tongnual, P., & Fields, M. L. (1979). Fermentation and relative nutritive value of rice meal and
chips. Journal of Food Science, 44(6), 1784-1785.
Toyoda, T., Daengsubha, W., Saisith, P., &Kozaki, M. (1979). Acid forming bacteria from
fermented rice noodle. Annual Report of International Center of Cooperative Research and
Development in Microbiology Engineering.
Tran, T. U., Suzuki, K., Okadome, H., Homma, S., & Ohtsubo, K. I. (2004). Analysis of the tastes
of brown rice and milled rice with different milling yields using a taste sensing system. Food
chemistry, 88(4), 557-566.
Trop Rice International Rice Research Institute (1998–2004). Main Milling Practices (pp. 199).
http://www.knowledgebank.irri.org/troprice/Main_Milling_Practices.htm.
Uchimura, T., Takao, T., Kikuchi, K., Niimura, Y., Okada, S., Ohara, N., ...&Kozaki, M. (1991).
Identification of lactic-acid bacteria isolated from fermented rice noodle khanomjeen of Thailand.
University of Ghana http://ugspace.ug.edu.gh
140
Journal of The Japanese Society For Food Science And Technology-Nippon Shokuhin Kagaku
KogakuKaishi, 38(6), 465-475.
UNICEF (1990). Strategy for improved nutrition of children and women in developing countries.
New York, UNICEF.
USAID (2009). Global food security response: West Africa rice value chain analysis,
MicroReport, No. 161, United States Agency for International Development (USAID),
Washington, D.C., USA.
USAID (2011).The Global Food Security Response West Africa Rice Value Chain Analysis:
Ghana Rice Study. Micro-report, USDA, 2011 Grain and Feed Annual Report.
Valous, N. A., Gavrielidou, M. A., Karapantsios, T. D., &Kostoglou, M. (2002). Performance of a
double drum dryer for producing pregelatinized maize starches. Journal of Food
Engineering, 51(3), 171-183.
Vandeputte, G. E., &Delcour, J. A. (2004). From sucrose to starch granule to starch physical
behaviour: a focus on rice starch. Carbohydrate polymers, 58(3), 245-266.
Verity, K., & Edwards, C. A. (1994). Resistant starch in young children. Proceedings of the
Nutrition Society, 53(1A), 105.
Walker, A.F., Pavitt, F. (1989). Energy density of Third World weaning foods. Nutrition
Bulletin, 14(2), 88-101.
Watanabe, T., Yamamoto, A., Nagai, S., &Terabe, S. (1998). Simultaneous measurement of
α‐amylase and glucoamylase activities in sake rice koji by capillary electrophoresis of sodium
dodecyl sulfate‐protein complexes and activity measurement of glucoamylase by in‐capillary
University of Ghana http://ugspace.ug.edu.gh
141
enzyme reaction method.Electrophoresis, 19(13), 2331-2337.
http://dx.doi.org/10.1002/elps.1150191313
Joint WHO/UNICEF/ICCIDD consultation on assessment of iodine deficiency disorders and
monitoring their elimination. A guide for program managers. Geneva: World Health
Organization, 2001:7–9.
William C.F.& Dennis C.W. (2011). Food Microbiology, Fourth edition, McGraw Hill, India, pp.
330.
Winquist, F., Wide, P., &Lundström, I. (1998, September). The combination of an electronic
tongue and an electronic nose for improved classification of fruit juices. In Technical Digest of
Eurosensors XII Conference, Southampton, UK, IOP, Bristol.
Wolever, T. M., Jenkins, D. J., Vuksan, V., Josse, R. G., Wong, G. S., & Jenkins, A. L. (1990).
Glycemic index of foods in individual subjects. Diabetes Care, 13(2), 126-132.
Yousaf, M. (1992). Study on some physicochemical characteristics affecting the cooking and
eating qualities of some Pakistani rice varieties (Doctoral dissertation, M. Sc. Thesis, Department
of Food Technology. University of Agriculture: Faisalabad).
Wang, H. H., Sun, D. W., Zeng, Q., & Lu, Y. (2000). Effect of pH, corn starch and phosphates on
the pasting properties of rice flour. Journal of food engineering, 46(2), 133-138.
Wolever, T.M.S & Mehling, C.  (2002).High-carbohydrate–low-glycaemic index dietary advice
improves glucose disposition index in subjects with impaired glucose tolerance. British Journal of
Nutrition, 87 (2).477–487.
University of Ghana http://ugspace.ug.edu.gh
142
Yousaf, M. (1992). Study on some physicochemical characteristics affecting the cooking and
eating qualities of some Pakistani rice varieties (Doctoral dissertation, M. Sc. Thesis, Department
of Food Technology. University of Agriculture Faisalabad).
Yousif, N. E., & El Tinay, A. H. (2000).Effect of fermentation on protein fractions and in vitro
protein digestibility of maize. Food Chemistry, 70(2), 181-184.
Zhang, G.,& Hamaker, B. R. (2009). Slowly digestible starch: Concept, mechanism, and proposed
extended glycemic index. Critical Reviews in Food Science and Nutrition, 49, 852–867.
Zhang, Y., Liu, W., Liu, C., Luo, S., Li, T., Liu, Y., Wu, D.&Zuo, Y. (2014).
Retrogradationbehaviour of high-amylose rice starch prepared by improved extrusion cooking
technology. Food chemistry, 158, 255-261.
Zhong, F., Li, Y., Ibáñez, A. M., Oh, M. H., McKenzie, K. S., & Shoemaker, C. (2009). The
effect of rice variety and starch isolation method on the pasting and rheological properties of rice
starch pastes. Food Hydrocolloids, 23(2), 406-414.
University of Ghana http://ugspace.ug.edu.gh
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APPENDIX A
BALLOT SHEET (POWDERED SAMPLES)
Panelist Code: ……………    Signature: ……………........ Date: ……………………………
Part One
Four coded samples have been placed before you. Please rate the intensity of each attribute
(appearance, aroma, flavour, after-taste and texture (a. mouthfeel and b.touch sensation))
using the intensity scale to assess each descriptor for each sample.
Sample code ……………..
APPEARANCE
Observe each sample in terms of colour, size, shape and surface texture and rate each attribute on
the respective intensity scale.
a. Yellow
b. Cream
c. White
extremenone
extremenone
extremenone
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d. Beige
e. Coarse
f. Fine
g. Dry
h. Crystalline
i. Fibrous
extremenone
extremenone
extremenone
extremenone
extremenone
extremenone
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Sample code ……………..
AROMA
Hold each sample close to your nose, smell and rate each attribute on the respective intensity
scale.
a. Milky
b. Starchy
c. Vanilla
d. Cardboardy
extremenone
extremenone
extremenone
extremenone
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e. Ricey
f. Gari
FLAVOUR
Put about half a spoonful of each sample into your mouth while moving the sample around in
your mouth to coat the whole oral cavity and all of your tongue while smelling. Then rate each
attribute on the respective scale.
Note: Take a bite of cracker and drink some water between samples at all times throughout
the session.
a. Milky
b. Sweet
extremenone
extremenone
extremenone
extremenone
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c. Maize/Corn
d. Sour
e. Roasted corn-soy bean flour
AFTER-TASTE
a. Sweet
b. Sour
extremenone
extremenone
extremenone
extremenone
extremenone
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Sample code ……………..
Place about half a teaspoonful of sample into your mouth, chew and cover your tongue and the
whole of your oral cavity. Rate the intensity of each attribute on the respective intensity scale.
Note: Take a bite of cracker and drink some water between samples at all times throughout
the session.
TEXTURE (a. mouth-feel)
a. Coarse
b. Fine
c. Gritty
d. Crunchy
extremenone
extremenone
extremenone
extremenone
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Sample code ……………..
TEXTURE (b. touch sensation)
Place half a teaspoon of each sample into a tissue given you and rub the sample between your
thumb, index and second fingers to feel the particles of each sample. Rate the intensity of each
attribute using the respective intensity scale.
a. Coarse
b. Fine
c. Gritty
extremenone
extremenone
extremenone
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BALLOT SHEET (RECONSTITUTED SAMPLES)
Panelist Code: ……………    Signature: ……………........ Date: ……………………………
Part One
Eight coded samples have been placed before you. Please rate the intensity of each attribute
(appearance, aroma, flavour, after-taste and texture(a. mouthfeel and b.touch sensation)) using
the intensity scale to assess each descriptor for each sample.
Sample code ……………..
APPEARANCE
Observe each sample in terms of colour, size, shape and surface texture and rate each attribute on
the respective intensity scale.
j. White
k. Cream
l. Beige
extremenone
extremenone
extremenone
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m. Particulate
n. Smooth
o. Pasty
AROMA
Hold each sample close to your nose, smell and rate each attribute on the respective intensity
scale.
g. Maize-like
h. Starchy
coarsefine
extreme
none
extremenone
extremenone
extremenone
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i. Fermented
j. Cardboardy
k. Ricey
FLAVOUR
Put about half a spoonful of each sample into your mouth while moving the sample around in
your mouth to coat the whole oral cavity and all of your tongue while smelling. Then rate each
attribute on the respective scale.
Note: Take a bite of cracker and drink some water between samples at all times throughout
the session.
f. Rich
extremenone
extremenone
extremenone
extremenone
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g. Sweet
h. Maize/Corn
i. Sour
j. Bland
k. Fermented
l. Ricey
extremenone
extremenone
extremenone
extremenone
extremenone
extremenone
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Sample code ……………..
AFTER-TASTE
c. Sweet
d. Sour
Place about half a teaspoonful of sample into your mouth, chew and cover your tongue and the
whole of your oral cavity. Rate the intensity of each attribute on the respective intensity scale.
Note: Take a bite of cracker and drink some water between samples at all times throughout
the session.
TEXTURE (a. mouth-feel)
a. Particulate
b. Gritty
c. Pasty
extremenone
extremenone
coarsefine
extremenone
extremenone
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Sample code ……………..
TEXTURE (b. touch sensation)
Place half a teaspoon of each sample into a tissue given you and rub the sample between your
thumb, index and second fingers to feel the particles of each sample. Rate the intensity of each
attribute using the respective intensity scale.
d. Particulate
e. Gritty
f. Smooth
g. Pasty
coarsefine
extremenone
extremenone
extremenone
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APPENDIX B
ANALYSIS OF VARIANCE FOR pH
Source df Sum of
squares
Mean
square
F P-value
Main Effects
A: Fermentation Time
B: Treatment
3
1
0.402
0.008
0.133912
0.007812
14.64
0.85
0.027
0.424
Interactions
A*B 3 0.027438 0.009146
Error 0
Total 7
ANALYSIS OF VARIANCE FOR LIGHTNESS VALUE (L*)
Source df Sum of
squares
Mean
square
F P-value
Main Effects
A: Fermentation Time
B: Treatment
3
1
14.2731
0.3528
4.7577
0.3528
5.06
0.37
0.108
0.584
Interactions
A*B 3 2.8231 2.8231 0.9410
Error 0
Total 7
ANALYSIS OF VARIANCE FOR REDNESS VALUE (a*)
Source df Sum of
squares
Mean
square
F P-value
Main Effects
A: Fermentation Time
B: Treatment
3
1
0.964
0.035
0.321
0.035
1.49
0.16
0.376
0.714
Interactions
A*B 3 0.647 0.216
Error 0
Total 7
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ANALYSIS OF VARIANCE FOR YELLOWNESS VALUE (b*)
Source df Sum of
squares
Mean
square
F P-value
Main Effects
A: Fermentation Time
B: Treatment
3
1
8.312
23.702
2.771
23.702
0.75
6.43
0.590
0.085
Interactions
A*B 3 11.055 3.685
Error 0
Total 7
ANALYSIS OF VARIANCE FOR WATER SOLUBILITY INDEX (WSI)
Source df Sum of
squares
Mean
square
F P-value
Main Effects
A: Fermentation Time
B: Treatment
3
1
57.503
4.968
19.168
4.968
2.60
0.67
0.227
0.472
Interactions
A*B 3 22.115 7.372
Error 0
Total 7
ANALYSIS OF VARIANCE FOR WATER ABSOPRTION INDEX (WAI)
Source df Sum of
squares
Mean
square
F P-value
Main Effects
A: Fermentation Time
B: Treatment
3
1
2.712
0.341
0.904
0.341
1.48
0.56
0.378
0.509
Interactions
A*B 3 1.837 0.612
Error 0
Total 7
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