University of Ghana http://ugspace.ug.edu.gh SENSORY AND PHYSICOCHEMICAL EVALUATION OF ‘‘BURKINA’’ MADE WITH COMPOSITE (COW AND TIGER NUT) MILK THIS THESIS IS SUBMITTED TO THE UNIVERSITY OF GHANA, LEGON IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF MPHIL HOME SCIENCE DEGREE BY PEARL NYARKO-MENSAH (10384854) May 2018 University of Ghana http://ugspace.ug.edu.gh DECLARATION I, Pearl Nyarko-Mensah hereby declare that except for the references which have been duly cited, the work in this thesis, “SENSORY AND PHYSICOCHEMICAL EVALUATION OF “BURKINA” MADE WITH COMPOSITE (COW AND TIGER NUT) MILK” was done entirely by me in the Department of Family and Consumer Sciences, School of Agriculture, College of Basic and Applied Sciences, University of Ghana, Legon. This work has never been presented either in whole or in part for any other degree in this University or elsewhere. …………………………………… Pearl Nyarko-Mensah (STUDENT) ………………………………………. ………………………………………. Professor Angelina O. Danquah Professor Firibu K. Saalia (SUPERVISOR) (SUPERVISOR) ………………………………………. Dr. Niilante Amissah (SUPERVISOR) i University of Ghana http://ugspace.ug.edu.gh ABSTRACT “Burkina”, a popular fermented milk beverage containing fermented millet agglomerates, is consumed in West Africa. Consumer behaviour towards “Burkina”, perceptions on its safety and potential for causing food borne illness, affects the distribution and sales of the product. Tiger nut, an underutilized crop in West Africa, with a rich nutty taste and unique mouthfeel has been incorporated into formulations for fermented milk products such as yoghurt, but not “Burkina”. The objectives of this study were to develop “Burkina” with tiger nut milk as a composite ingredient, determine consumers’ behaviour towards “Burkina” and “Burkina” made with composite (cow and tiger nut) milk and determine the physicochemical properties, consumer preference and microbiological quality of the product. “Burkina” was prepared with (0 %, 2 % and 4 %) milk fat, with or without 40 % Tiger nut milk (TNM) and analysed in triplicate for pH, colour, proximate composition and minerals. Students and staff of the University of Ghana were carefully selected for Consumer Focus Group Discussions (CFGDs) using a recruitment questionnaire and an interview guide respectively. Consumer preference for “Burkina” was also determined using an untrained panel. Standard methods for microbiological analysis were used. Descriptive statistics involving frequencies and central tendency were employed in data analysis and reporting. Data collected from the study was subjected to Analysis of Variance (ANOVA) in Statistical Analysis Software (SAS/STAT, University Edition). The global theme obtained from the CFGDs was segregated into sub- themes and the results were thematically analyzed using Attride-Stirling’s method with the aid of ATLAS.ti.7 software. The addition of TNM increased the carbohydrate, protein, fat and ash content of “Burkina”, but moisture content decreased. The pH was acidic (3.78 – 3.98) and was unaffected by the addition of TNM. The L value of “Burkina” decreased (became darker) with the addition of TNM, while mineral values (K, Na, Mg, P) increased but Ca levels decreased as tiger nuts contain less Ca than milk. There were no counts for ii University of Ghana http://ugspace.ug.edu.gh salmonella, coliforms, E. coli and Staphylococcus aureus but there were low counts for yeast and molds (within the acceptable range) in “Burkina” with TNM. “Burkina” flavour was unaffected by the addition of TNM. However “Burkina” with TNM had lower ratings for overall acceptability, aroma, colour, after taste and mouthfeel. Affordability and vendor proximity were major facilitators of “Burkina” patronage, while packaging was an average facilitator. Product safety and storage temperature were major barriers to the purchase and consumption of “Burkina”. The results suggest alternative uses for tiger nuts. Optimizing the amount of TNM added to “Burkina” may create “Burkina” with an enhanced nutritional profile and improved sensory properties. It may also increase the consumption of dairy milk beverages for improved nutrition, while improving upon the quality, safety and appeal of “Burkina” among Ghanaian consumers. . iii University of Ghana http://ugspace.ug.edu.gh DEDICATION This thesis is dedicated to the Almighty God, the Nyarko-Mensah family and my supervisors. It is also dedicated to all researchers and entrepreneurs in this area of research, as well as all those who contributed in diverse ways to make this research come to fruition. iv University of Ghana http://ugspace.ug.edu.gh ACKNOWLEDGEMENTS I wish to express my sincerest gratitude to my Father in Heaven for granting me the grace, strength and wisdom to complete this research. I also express profound gratitude to my supervisors; Dr. Niilante Amissah, Professor Angelina Danquah and Professor F. K. Saalia, for their encouragement, and immense contribution to this work. My appreciation goes to Dr. M.Y.B. Adjei and Dr. A. Parry-Hanson Kunadu from the Department of Nutrition and Food Science for their contributions. I am indebted to the A. G. Leventis Foundation for providing me with the grant for this research. Special thanks go to Dr. Ernest Afrifa-Anane of the Regional Institute for Population Studies, Mr. Crossby Osei Tutu Junior, Mr. Reuben Acheampong, Ms. Nayram Doe, Ms. Matilda Twumasi and Ms. Jacqueline Baaba Acquah of the Department of Family and Consumer Sciences for their support in diverse ways to make this research successful. I wish to express my gratitude to my Dad, Mr. Gerald Nyarko-Mensah who contributed to the success of my research. I am also very grateful to my Mom, Mrs. Thelma Nyarko-Mensah and my siblings, Samantha and Jewell, for their unwavering support. My appreciation goes to Mr. Daniel Apartey of Ghana Atomic Energy, Dr. Lawrence Abbey and Dr. Charlotte Oduro-Yeboah of Food Research Institute for their assistance with the Microbiological Analysis, Proximate Analysis, Mineral Composition and colour analysis. My deepest gratitude to all Lecturers at the Department of Family and Consumer Sciences whose contribution in one way or the other led to the completion of this research. v University of Ghana http://ugspace.ug.edu.gh TABLE OF CONTENTS CONTENT PAGE DECLARATION i ABSTRACT ii DEDICATION iv ACKNOWLEDGEMENTS v TABLE OF CONTENTS vi LIST OF TABLES xii LIST OF FIGURES xiii LIST OF ACRONYMS xiv CHAPTER ONE 1.0 INTRODUCTION 1 1.1 Background Information 1 1.2 Statement of the Problem 4 1.3 Aim of the Study 4 1.4 Objectives of the Study 4 1.5 Hypotheses 5 1.6 Significance of the Study 5 CHAPTER TWO 2.0 LITERATURE REVIEW 6 2.1 Milk 6 vi University of Ghana http://ugspace.ug.edu.gh 2.1.1 Composition of Milk 6 2.1.2 Health Benefits of Milk 9 2.1.3 Uses of Milk 11 2.1.4 Dairy Products 11 2.1.4.1 Fermented Milk 12 2.1.4.1.1 “Burkina” 13 2.1.4.2 Cheese (“Wagashie”) 14 2.1.4.3 Yoghurt 14 2.2 Tiger Nuts 15 2.2.1 Composition of Tiger Nuts 17 2.2.2 Health Benefits of Tiger Nuts 18 2.2.3 Uses of Tiger Nuts 20 2.2.3.1 Tiger Nut Oil 21 2.2.3.2 Tiger Nut Flour 22 2.2.3.3 Tiger Nut Milk 23 2.3 Other Vegetable Milk 24 2.4 Composite Milk 25 2.4.1 Products from Composite Milk 27 2.5 Microbiology of Milk and Dairy Products 28 2.6 Sensory Evaluation of Milk and Dairy Products 28 vii University of Ghana http://ugspace.ug.edu.gh 2.7 Packaging of Milk and Dairy Products 29 CHAPTER THREE 3.0 MATERIALS AND METHODS 31 3.1 Materials 31 3.1.1 Ingredients 31 3.1.2 Tools, Equipment and Chemicals 31 3.2 Methods 31 3.2.1 Preparation of Tiger Nuts for Milk Extraction 31 3.2.1.1 Cleaning and Soaking of Tiger Nuts 31 3.2.1.2 Tiger Nut Treatment 32 3.2.1.3 Milling of Tiger Nuts and Extraction of Tiger Nut Milk 32 3.2.2 Pearl Millet Treatment and Agglomeration 33 3.2.3 Production of ‘‘Burkina’’ Made with Cow’s Milk 35 3.2.4 Preparation of ‘‘Burkina’’ Made with Composite (Cow and Tiger Nut) Milk 35 3.2.5 Packaging and Storage of ‘‘Burkina’’ Samples 36 3.3 Colour Determination of ‘‘Burkina’’ Samples 36 3.4 Determination of pH for ‘‘Burkina’’ Samples 37 3.5 Proximate and Mineral Composition of the Homogenous and Composite 37 Blends of ‘‘Burkina’’ 3.5.1 Protein Determination 38 viii University of Ghana http://ugspace.ug.edu.gh 3.5.2 Ash Determination 39 3.5.3 Moisture Determination 39 3.5.4 Fat Determination 40 3.5.5 Carbohydrate Determination 40 3.6 Mineral Composition of the Homogenous and Composite Blends of “Burkina” 41 3.7 Microbiological Analysis of “Burkina” Samples 41 3.8 Sensory Evaluation 42 3.8.1 Focus Group Discussion 42 3.8.2 Consumer Acceptance Test 42 3.9 Study Design and Data Analysis 43 CHAPTER FOUR 4.0 RESULTS AND DISCUSSION 44 4.1 Proximate Composition of ‘‘Burkina’’ Samples 44 4.1.1 Moisture Content 45 4.1.2 Fat Content 45 4.1.3 Carbohydrate and Protein Content 46 4.1.4 Total Ash Content 46 4.2 Mineral Composition of ‘‘Burkina’’ Samples 47 4.3 pH of “Burkina” Samples 48 ix University of Ghana http://ugspace.ug.edu.gh 4.4 Microbiological Wholesomeness of “Burkina” Samples 49 4.5 Instrumental Colour Analysis of “Burkina” samples 51 4.6 Consumer Focus Group Discussion and Sensory Evaluation of “Burkina” Samples 52 4.6.1 Consumer Focus Group Discussion 52 4.6.1.1. Perceptions of Fermented and Flavoured Milk 53 4.6.1.2 Perceptions of Whole and Skimmed Milk 55 4.6.1.3 Perceptions of ‘‘Burkina’’ 57 4.6.1.4 Facilitators to the Purchasing and Consumption of ‘‘Burkina’’ 60 4.6.1.5 Barriers to the Purchasing and Consumption of ‘‘Burkina’’ 61 4.6.1.6 Perceptions of ‘‘Burkina’’ with Tiger Nut 63 4.6.2 Sensory Evaluation of “Burkina” samples 65 CHAPTER FIVE 5.0 SUMMARY, CONCLUSION AND RECOMMENDATIONS 67 5.1 Summary 67 5.2 Conclusion 68 5.3 Recommendations 68 REFERENCES 69 APPENDICES x University of Ghana http://ugspace.ug.edu.gh Appendix 1: Recruitment Questionnaire for Focus Group Discussion 79 on ‘‘Burkina’’ Product Appendix 2: Consent Form 82 Appendix 3: Analysis of Variance Results for Sensory Attributes 85 Appendix 4: ‘‘Burkina’’ Themes and Codes for FGD 86 Appendix 5: Discussion Guide for Focus Group Discussion 88 xi University of Ghana http://ugspace.ug.edu.gh LIST OF TABLES TABLE PAGE Table 1: The Milk Chemical Composition of Some Mammalian Milk ( % ) 9 Table 2: Proximate Composition of ‘‘Burkina’’ Samples 44 Table 3: Mineral Composition of ‘‘Burkina’’ Samples 48 Table 4: Mean pH of ‘‘Burkina’’ samples 49 Table 5: Microbiological Analyses of ‘‘Burkina’’ Samples (Mean Counts) 50 Table 6: Mean Colour (L, a, b) and ∆ E Values for ‘‘Burkina’’ Samples 51 Table 7: Characteristics of FGD Participants 52 Table 8: Mean Sensory Scores of ‘‘Burkina’’ Samples 66 xii University of Ghana http://ugspace.ug.edu.gh LIST OF FIGURES FIGURE PAGE Figure 1: Types of Tiger Nuts Grown in Ghana 16 Figure 2: Examples of Products made with Tiger Nuts 21 Figure 3: Concept of Composite Dairy Foods including Milk Composites 27 Figure 4: Flow Chart Showing Tiger Nut Milk Extraction Process 33 Figure 5: Flow Chart Showing the Production of Fermented Pearl Millet 34 Agglomerates Figure 6: Understanding the Desirability of “Burkina” 53 Figure 7: Perceptions of Flavoured and Fermented Milk 55 Figure 8: Perceptions of Skimmed and Whole Milk 57 Figure 9: Respondents Perceptions on ‘‘Burkina” 59 Figure 10: Facilitators to the Purchasing and Consumption of ‘Burkina’ 61 Figure 11: Barriers to the Purchasing and Consumption of ‘‘Burkina’’ 63 Figure 12: Perceptions of ‘‘Burkina’’ with Tiger Nut Milk 64 xiii University of Ghana http://ugspace.ug.edu.gh LIST OF ACRONYMS AAS Atomic Absorption Spectrophotometer BA Blood Agar ANOVA Analysis of Variance CFDGs Consumer Focus Group Discussions FAO Food and Agriculture Organisation FCM Full Cream Milk FCMT Full Cream Milk with Tiger Nut Milk FGD Focus Group Discussion GSA Ghana Standard Authority HCl Hydrochloric Acid MC Maconkey Agar NaOH Sodium Hydroxide OA Osteoarthritis OGY Oxytetracycline Glucose Yeast Extract PCA Plate Count Agar PET Polyethylene Terephthalate SM Skimmed Milk SMT Skimmed Milk with Tiger Nut Milk SSM Semi-skimmed Milk xiv University of Ghana http://ugspace.ug.edu.gh SSMT Semi-skimmed Milk with Tiger Nut Milk TNM Tiger Nut Milk UHT Ultra High Temperature USA United States of America USDA United States Department of Agriculture WHO World Health Organisation XLD Xylos Lysine Deoxycholate Agar xv University of Ghana http://ugspace.ug.edu.gh CHAPTER ONE 1.0 INTRODUCTION 1.1 Background Information The addition of milk to diets is being advocated to improve human nutrition. Milk is known to deteriorate quickly in high temperatures and therefore requires processing to extend shelf- life, to enable the final product reach distant markets. Once milk is processed, its shelf life may be extended to two weeks, depending on milk quality, packaging and storage temperature (Bille et al., 2000). Products obtained from cow’s milk include ice cream, cheese, yoghurt and milk-based desserts. Some of these products are made through fermentation, separation of milk components or both (Pamplona-Roger, 2006). ‘‘Burkina’’, also known as “Brukina”, is a fermented dairy beverage that contains fermented millet agglomerates (Caiquo & Mensah, 2013). ‘‘Burkina’’ has its origins from ‘Burkina’ Faso and its original name is 'Deger' (Appiah, 2013). Some West African countries also refer to the beverage as “nunu de fura” (Caiquo & Mensah, 2013). ‘‘Burkina’’ is popular among consumers in Ghana especially within Accra because of its resemblance to fresh yoghurt. ‘‘Burkina’’ forms part of a family of fermented beverages (such as yoghurt, kefir, koumiss, sour milk), which dates back to early civilization around 10,000 BC, when human beings progressed from hunting and gathering to food processing (Rašić & Kurmann, 1978; Pederson, 1979). The beverage is popular in Northern Ghana and is making inroads in popularity in Southern Ghana, especially in Accra where it is sold in Supermarkets, Stores and at Traffic Lights (GNA, 2013). The main ingredients for the preparation of ‘‘Burkina’’ are fresh or powdered cow milk or a combination of both, millet (pearl millet), sugar and sometimes salt for taste (Osei-Onomah, 2014). ‘‘Burkina’’ drinks are packaged and sold in 1 University of Ghana http://ugspace.ug.edu.gh transparent plastic bottles or polyethylene bags (Appiah, 2013). The beverage can be consumed immediately after processing or stored in a refrigerator for a maximum of two weeks (Appiah, 2013; Johnson et al., 2013). ‘‘Burkina’’ production results in a stable and viscous final product. ‘‘Burkina’’ produces a mouth feel of a thick smooth (yoghurt-like) texture with small lumps and a grainy feel of millet (Caiquo & Mensah, 2013). Due to the fermentation of millet and milk, this beverage has a rather sour taste with pH of 4.6 (Caiquo & Mensah, 2013). ‘‘Burkina’’ has a network of aggregated casein particles (casein micelles) held together in chains. It also has a suspension of tiny particles of millet (Caiquo & Mensah, 2013). ‘‘Burkina’’ is a very nutritious beverage, consisting of proteins, essential vitamins (Vitamin A, B6, B12, D, riboflavin, pantothenic acid, niacin, thiamine, folate), dietary fiber, carbohydrates, fat, as well as minerals (calcium, magnesium, manganese, potassium, iron, phosphorus, zinc and copper). Some studies have even proven the probiotic potential (due to the fermentation process) of ‘Burkina’ (Caiquo & Mensah, 2013). ‘‘Burkina’’ may however cause food poisoning when it is prepared and packaged under unhygienic conditions (Amadou et al., 2011). Most vendors, unfortunately, have little or no knowledge about food safety and hygiene practices posing a health hazard to consumers (FAO/WHO, 2012). Tiger nut (Cyperus esculentus), locally known in Ghana as “Atadwe”, is an underutilised crop with potential for utilization in food products due to its nutrient composition and health benefits. Tiger nuts are a rich source of phosphorus, potassium, magnesium, iron and zinc (Chiemela et al., 2010). There are two main types grown in Ghana; the Kwahu type (yellow and brown in colour) and the Fante type (brown in colour). Some of the health benefits of tiger nuts indicated by researchers include; its aid in the reduction of hypertension, cardiovascular diseases and stroke (Belewu & Belewu, 2007; Esteshola & Oraedu, 1996), aid in the prevention of digestive tract disease such as colon cancer (Caiquo & Mensah, 2013), 2 University of Ghana http://ugspace.ug.edu.gh ideal for diabetics (Type 2), celiac and lactose intolerant people (Chevailler, 1996; Lu & Wang, 2017), remedy for indigestion, flatulence and diarrhoea (Chevailler, 1996), and promotion of good skin, bone development, fertility and muscle contraction (Chevailler, 1996). Tiger nuts have been incorporated into many food products such as: biscuits and cakes from tiger nut composite flour (Ade-Omowaye et al., 2008, Chiemela et al., 2010, Frimpong, 2016), yogurt (Sanful, 2009), drinks (Abraham, 2013), fortified weaning foods (Ikepeme et al., 2012), desserts (Nyarko-Mensah et al., 2015) and cheese (Tijani, 2014). Some researchers [Sanful, (2009); Tijani, (2014)] posited in their studies that panelists in sensory tests of dairy products that incorporated tiger nuts showed a preference for products with up to 50 % tiger nut. Pearl millet (Pennisetum glaucum), is an indigenous cereal crop grown in West Africa for its edible grains and straw (Desikachar, 1996). Pearl millet is also a useful food which can be made into fermented ‘‘Burkina’’s (roti), fermented foods (kisra and gallettes), thin and thick porridges (toh), steam-cooked dishes (couscous); non-alcoholic beverages, and snacks (Desikachar, 1996). The millet grains are also used as feeds for local animals. Pearl millet is used as brewer’s grain as it is richer in calcium, magnesium, iron and copper than most cereals but poorer in potassium, sodium, lead and manganese (Chukwu & Abdulir, 2008). This study sought to prepare ‘‘Burkina’’ which is safe for consumption, incorporate tiger nut milk into the formulation and processing of ‘‘Burkina’’ and to determine the physicochemical and sensory properties of ‘‘Burkina’’ made with or without tiger nut milk. 3 University of Ghana http://ugspace.ug.edu.gh 1.2 Statement of the Problem ‘‘Burkina’’ is a popular fermented dairy product that contains fermented millet agglomerates. However, recent research has shown that depending upon the processing and packaging conditions used, “Burkina” may be unsafe for consumption with the potential for causing food borne illnesses due to contamination during and after processing. Preparing ‘‘Burkina’’ under hygienic conditions may improve the safety of ‘Burkina’ and incorporating tiger nut in the final product may also create a new product with sensory properties that may appeal to Ghanaian consumers. Incorporation of tiger nut milk into “Burkina” will not only increase the nutritional value of the product but may also add on to the health benefits as well. This may improve the patronage of ‘Burkina’ and increase the utilization of tiger nuts. 1.3 Aim of the Study The aim of the study was to incorporate tiger nut milk into the processing method for ‘‘Burkina’’ prepared under hygienic conditions and determine the physicochemical and sensory properties of ‘‘Burkina’’ with incorporated tiger nut milk. 1.4 Objectives of the Study The specific objectives were to: 1. Develop “Burkina” with tiger nut milk as a composite ingredient. 2. Determine the physicochemical and sensory properties of “Burkina” and “Burkina” made with tiger nut milk. 3. Determine consumers’ perception on ‘Burkina’ and ‘Burkina’ made with tiger nut milk. 4 University of Ghana http://ugspace.ug.edu.gh 1.5 Hypotheses Ho1: The addition of tiger nut milk to the processing of ‘‘Burkina’’ does not affect the physicochemical properties of ‘‘Burkina’’. Ho2: The addition of Tiger nut does not influence the sensory characteristics of “Burkina” made with composite milk. 1.6 Significance of the Study This study is significant because it may contribute to: 1. Documenting an optimized protocol for processing and packaging “Burkina” with tiger nut milk to improve product shelf life and consumer safety. 2. The addition of value to cow milk and tiger nuts and encourage an increase in the consumption of cow milk and tiger nuts (an underutilized crop in Ghana). 3. Providing opportunities for entrepreneurship and income generation from both cow milk and tiger nuts. 5 University of Ghana http://ugspace.ug.edu.gh CHAPTER TWO 2.0 LITERATURE REVIEW 2.1 Milk Mammalian females have a mammary gland with a lactating function which is to secrete a white liquid known as “milk” (Grădinaru et al., 2015). All mammalian females, including humans, will normally produce milk to feed their offspring until they are ready for solid food. Milk is one of the major foods for humans, and an important preliminary base in different human productive activities (Robinson, 1994). Milk consists of major ingredients (water, lipids, sugar and proteins) and minor ingredients (minerals, vitamins, hormones and enzymes). The concentration of these ingredients vary among species, with the major ones being lipids (2 % – 55 %), proteins (1 % – 20 %), lactose (0 % – 10 %) (FitzGerald & Meizel, 2003). Cattle are the primary source of mammalian milk in most parts of the world, except the Indian subcontinent and portions of the Mediterranean region, Middle East and Africa, where buffalos, sheep and goats make a vital contribution to national milk production (Tamime, 2006). The Middle East, Northern and Eastern Africa’s deserts use camels for their milk production. Reindeer in Lapland, and mares in Central Asia are the other species used in obtaining milk (Tamime, 2006). 2.1.1 Composition of Milk Milk contains water, fat, protein, carbohydrate (lactose), and minerals (ash) as its major components (Robinson, 1994). However, there are other extremely important micronutrients such as vitamins, essential amino acids, and trace minerals. Several other chemicals (over 250) have also been recognised in milk (Robinson, 1994). The Food and Drug Authority of 6 University of Ghana http://ugspace.ug.edu.gh United States stated that milk used for beverages should contain at least 8.25 % milk solids and at least 3.25 % milk fat (Fox, 2003). Species, geographic position, and new-born needs influence milk composition. Milk is as enriched in its composition as new-born requirements for a quick gain in weight are. The milk sugar proportion is related to brain development, and milk fats are in a higher concentration in animals located in cold areas (Maloş et al., 2002). With the exception of the iron, copper and Vitamin C content, milk could be considered a complete food for human nutrition needs (Banu, 2002; Rusu, 2005). Water represents the largest component of milk, being important for its solvent properties and a good vehicle for other milk ingredients (Fox, 2003). Fats or oils, which are known collectively as lipids, are components of biological fluids, tissues and foods which are dissolvable in an apolar solvent (Fox, 2003). Milk fats are the most adaptable compounds, being under the influence of species, breed, lactation stage, feeding, season, and health condition (Rotaru & Moraru, 1997; Şindilar 1998). Milk nitrogen compounds can be protein or non-protein. Milk and dairy products contain all essential amino acids and represent an important source of proteins of high nutritive value. The protein content greatly affects the properties of milk and milk products more than any other constituent (Fox, 2003). A major milk protein is casein, which exists as a multi-subunit protein complex dispersed throughout the fluid phase of milk. Under certain conditions the casein complexes are disrupted, causing curdling of the milk. Curdling results in the separation of milk proteins into two distinct phases, a solid phase (the curds) and a liquid phase (the whey) (Fox, 2003). Casein and whey proteins are the main groups of proteins which make up about 80 % and 20 % respectively of total milk protein. The acid whey contains two groups of proteins; 7 University of Ghana http://ugspace.ug.edu.gh lactalbumins and lactoglobulins (Fox, 2003). Milk carbohydrates consist of lactose and other sugars in a low amount (such as glucose, galactose). They are the second largest compounds in milk (Banu 2002; Iurcă 1998; Mihaiu & Mihaiu 1998). Despite their large numbers, milk enzymes are in small concentrations, located at the lipoprotein membrane of fat globules, at the casein micelle, or in solution. Milk contains almost all of the liposoluble (A, D, E, K) and hydrosoluble (B and C) vitamins in their well-proportioned amounts (Grădinaru et al., 2015). Milk pigments are from inner and outer origins. The most crucial pigments of animal origin, lacto Flavin and riboflavin colour milk in a greenish-blue and yellowish-beige, respectively. The outer layer pigments are taken from animal feed or due to milk adulteration with milk microorganisms containing pigment (Grădinaru et al., 2015). The most important outer layer pigment is carotene. On the other hand, xanthophyll and chlorophyll can also be found in milk. Gases such carbon dioxide, nitrogen and oxygen are in larger quantities than ammonia and hydrogen sulphide in freshly milked milk (Grădinaru, 2015). Milk minerals are characterised either by soluble or insoluble salts (chlorides, phosphates, citrates), or by bound-forms by milk proteins, especially caseins (Banu, 2002; Ciotău 2006). Table 1 shows the composition of fresh fluid milk and other dairy products. 8 University of Ghana http://ugspace.ug.edu.gh Table 1: The Chemical Composition of Some Mammalian Milk (%) Species Fats Proteins Lactose Minerals Total Water Solids Cow 3.5 3.1 4.9 0.7 12.2 87.8 (Holstein) Cow(Jersey) 5.5 3.9 4.9 0.7 15.0 85.0 Sheep 5.3 5.5 4.6 0.9 16.3 83.7 Goat 3.5 3.1 4.6 0.8 12.0 88.0 Human 4.5 1.1 6.8 0.2 12.6 87.4 Source: Jensen, 1995. 2.1.2 Health Benefits of Milk According to Antinoro (2012), potassium, an important component of milk, can provide health benefits such as; protection against muscle wasting, osteoporosis, cardiovascular diseases and kidney stones. Milk consumption has been attributed to its crucial role in bone health. The role milk plays in the development of knee osteoarthritis (OA) was observed radiographically by Bing et al. (2014). From the study, it was concluded that regular milk intake was positively connected to a decreased progression in OA in women (Bing et al., 2014). Fat content ranges from 2.8 % to 8.1 %, depending on the breed of the cattle, nutritional aspects, individual characteristics, lactation period, milk production hygiene and season. It is also one of the most crucial constituents in bovine milk (Miciński et al. 2018). According to Miciński et al. (2018) the exceptional nutritional value of bovine milk can be accredited to the presence of short and medium-chain fatty acids which are important sources of energy for 9 University of Ghana http://ugspace.ug.edu.gh the muscles, heart, liver, kidneys, blood platelets and nervous system. Bovine milk does not pose an obesity risk; prevents ulcerative colitis, cancer, atherosclerosis and hypertension; has anti-inflammatory and antibacterial effects, and boosts natural immunity. Miciński et al. (2018) postulated that milk contains cholesterol. The cholesterol is a lipid derivative which steadies and hardens the cell membranes, forms the cell cytoskeleton, protects nerve fibers and acts as a precursor of steroid hormones, bile acids and vitamin D3. Bovine milk lipids, on the other hand, do not exert hypercholesterolemic or atherogenic effects in the human body (Miciński et al., 2018). The American Heart Association however stated that, milk comprises saturated fat, which can raise the levels of cholesterol up. According to the USDA National Nutrient Database, a one-cup serving of whole milk comprises 9 grams of total fat, which includes 6 grams of saturated fat (Miciński et al., 2018). Reduced fat milk, such as skimmed milk (2 %), contains about half the amount of total and saturated fat as whole milk. The fats drop to 2.4 grams of total fat and 2 grams of saturated fat in 1 % fat milk. The American Heart Association has therefore suggested limiting saturated fat intake to less than 7 percent of total daily calories (Miciński et al., 2018). Some claims have been made about the likely health benefits that could theoretically be derived from the intake of raw milk as against that of pasteurized milk (Miciński et al., 2018). However, recent scientific reviews by different international groups have posited that there is no reliable scientific evidence to back the proposed health benefits of raw milk. For instance, it has been said that milk has probiotic effects. According to Sanders (2008), the term "probiotic" should be used only for products that contain enough live microbes which have been acknowledged in target-host research to convene a health benefit. Probiotics must be recognized to the level of strain, must be characterized for the specific health target, and 10 University of Ghana http://ugspace.ug.edu.gh must be formulated into products using strains and doses shown to be effective. Sanders (2008) therefore postulated that raw milk does not meet this definition. 2.1.3 Uses of Milk Milk can be manufactured into various products such as cream, butter, yogurt, kefir, ice cream, and cheese. It can again be used to make casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additives and industrial products by modern processing (Harness, 2018). It can also be used as a skin softening ingredient for facial or full body treatment and as a mild makeup remover as it contains naturally cleansing enzymes. Since the creamy base of milk makes it a great moisturizer, it is a substitute for shaving cream and is also helpful to areas often irritated by shaving (Harness, 2018). Other uses for milk include; shining up leather bags or shoes, polishing of silverware, and removing ink stains from clothing. Milk, when used as a marinade on fish, masks the ‘fishy’ aftertaste and makes it taste fresh in the mouth (Harness, 2018). 2.1.4 Dairy Products Dairy products are a type of food produced from or containing the milk of mammals, primarily cattle, water buffalo, goat, sheep and camel (Lu & Wang, 2017). Examples of dairy products include: powdered milk or milk powder (which is produced by evaporating water from whole, reduced fat or skimmed milk); condensed milk (milk concentrated by evaporation); infant milk (which is powdered milk with specific additives for feeding infants); skimmed milk containing about 0.1 % fat and is made when all the cream (milkfat) is removed from whole milk; buttermilk which is the liquid left over after producing butter from cream and is often dried as livestock feed (Lu & Wang, 2017). Examples of other dairy products include cheese, 11 University of Ghana http://ugspace.ug.edu.gh produced by coagulating milk, separating curds from whey and letting the curds ripen, generally with specific bacteria and sometimes moulds; Butter, consisting mostly of milk fat is produced by churning cream; Ghee, which is a form of clarified butter, made by gentle heating of butter and removal of the solid matter, and Cream cheese produced by the addition of cream to milk which is then curdled to form a rich curd or cheese. Curds are the soft, curdled part of milk (or skim milk) used to make cheese (Tijani, 2014). Yoghurt is made from milk fermented by Streptococcus salivarius spp thermophilus and lactobacillus spp bulgaricus and sometimes with an additional bacteria, such as Lactobacillus acidophilus (FitzGerald & Meisel, 2003). Ice cream is made from cream that is frozen slowly with milk, flavours and emulsifying additives (dairy ice cream). Ice milk is a low-fat version of ice cream. Whey is the liquid milked from curds and used for further processing or as a livestock feed (Wong, 2013). 2.1.4.1 Fermented Milk Fermented milk products are dairy products that have been cultured with lactic acid bacteria such as Lactobacillus, Lactococcus and Leuconostoc (Caplice & FitzGerald, 1999). Fermentation is used for many purposes, which include, extending the shelf life of foods, producing desirable taste and flavour, enhancement of nutritional value, producing required physicochemical properties, improvement of food safety and food security (Caplice & FitzGerald, 1999). Fermented food and beverages were first produced thousands of years ago and remain an important part of man’s diet, supplying about 20 % - 40 % of food worldwide (Campbell-Platt, 1994). A range of different Lactobacilli strains have been grown in laboratories allowing for a vast range of cultured milk products with varied tastes (Campbell- Platt, 1994). 12 University of Ghana http://ugspace.ug.edu.gh According to Guarner & Schaafsma (1998), probiotics are live microbes which positively influence the intestinal microflora of their host. Fermented dairy foods including yoghurt and cheese are a preferred medium for health promoting bacteria as they contain lactose and peptides (Schiffrin & Blum, 2002). They provide the most suitable nourishment for the conveyance of these beneficial bacteria to the human gut, once the environment is suitable to sustain these cultures (Ricke & Pillai, 1999; Schiffrin & Blum, 2002). The consumption of fermented dairy foods as functional foods is currently on the increase because of the live bacteria, as well as their highly digestible nature (FitzGerald & Meisel, 2003). 2.1.4.1.1 ‘‘Burkina’’ ‘‘Burkina’’ is a fermented food drink made from millet and cow milk. The product originated from Burkina Faso, hence the name, and was initially confined to the three Northern regions of Ghana but is now seen all over the streets of Accra and other regional capitals of Ghana (Caplice & FitzGerald, 1999). The product is also refered to as “deger” or “nunu de fura” in some parts of West Africa. ‘‘Burkina’’ emerged from two already existing indigenous products namely “nunu” which is a spontaneously fermented milk and “fura”, a traditional food made from spontaneously fermented millet (Caplice & FitzGerald, 1999). Mashing and mixing the two together and adding sugar and sometimes spices gave rise to the drink now known as ‘‘Burkina’’ (Caplice & FitzGerald, 1999). The cooking, fermentation and pasteurisation processes involved in the production of ‘‘Burkina’’ when done hygienically, give rise to a microbiologically safe product with a refrigerated shelf life of about two weeks (Campbell-Platt, 1994). “Burkina” is a nutritious product rich in proteins, carbohydrates, minerals and essential vitamins. Some studies have confirmed the probiotic nature of ‘‘Burkina’’ owing to the fermentation process (Caiquo & Mensah, 2015; Caplice & FitzGerald, 1999). 13 University of Ghana http://ugspace.ug.edu.gh 2.1.4.2 Cheese (“Wagashie”) Cheese is a dairy food obtained from milk that is produced in a vast range of flavours and textures. Cheese is obtained from the coagulation of casein (milk protein) with rennet (enzyme) after acidification and comprises of proteins and fat from milk, usually from cows, buffalo, goats, or sheep (Sessou et al., 2015). Curds are separated from whey and pressed into a more solid form. Cheeses may have molds on the rind, the outer layer, or throughout; depending on the type. Majority of cheese melt at cooking temperature (Sessou et al., 2015). Different types of cheese are produced worldwide from various countries. The styles, textures and flavours of cheese depend on the extent of pasteurization, the butterfat content, ageing, processing, bacteria and mold content (Rusu, 2005). “Wagashie” is a type of cheese made from cow’s milk. It is a speciality of northern Benin in West Africa and is commonly made by the Fulani people. It is relatively soft in texture and mild in flavour and is frequently used in cooking. It is commonly sold in the Northern regions of Ghana (Arthur, 2016). The name is not to be confused with “Wagashi” which refers to a type of Japanese confectionary (Morisaki & Suda, 2017). “Wagashie” is a generally creamy to white soft cheese that is brine pickled and without a rind. The cheese is salty and slightly sour and sold in pieces of ½ pound (0.227 kg) to 1 pound (0.454 kg) (Arthur, 2016). 2.1.4.3 Yoghurt Yoghurt is known to be one of the popular fermented foods which contains Lactobacillus sp. (Analie & Bennie, 2001). Examples of such products are yoghurt mousse, reduced probiotic yoghurts, fat content yoghurts, drinkable yoghurts, yoghurt shakes, yoghurt ice-cream etc. (Fiszman & Salvador, 1999). The balance of microflora in the gut is believed to be improved by live bacteria in yoghurt, as it competes with the pathogens in the gut for nutrients and 14 University of Ghana http://ugspace.ug.edu.gh space, thereby enhancing one’s health (Fuller 1989; Fuller, 1992; Ledenbach & Marshall, 2009). During the reduction process involved in the conversion of bile into non-carcinogenic bile acids by the probiotics in yoghurt, harmful compounds like nitrites and nitrates are disengaged before they convert to nitroamines (Commane et al., 2005). Liong & Shah (2006), posited that the consumption of yoghurt can aid in the reduction of cholesterol in the blood; as the live cultures in yoghurt are able bind the bile acids or assimilate the cholesterol or both (Guarner & Schaafsma, 1998). People who are either lactose intolerant or have some kind of protein allergy can consume yoghurt as the culturing process makes it much easier to digest (Bertrand-Harb et al., 2003). 2.2 Tiger Nuts Tiger nut (Cyperus esculentus L.), is a member of the family Cyperaceae. Though popularly called “chufa” in many places it has other common names, such as earth nut, tiger nut, yellow nutsedge and “Zulu” nut. It is also called “ayaya” in Hausa and “ofio” in Yoruba (Umerie & Enebeli, 1997; Pascual et al., 2001). Tiger nut is known to have trade names like yellow nutgrass, ground almond, Zulu nut, edible rush, chufa and rush nut (Esteshola & Oraedu, 1996). It belongs to the same genus as the papyrus plant (very common plant in seasonally flooded wetlands) and is a multicultural perennial crop (Bamishaiye, 2011). In the tropics, it is found largely in India and West Africa (Cobley, 1962). Tiger nuts were used to preserve the bodies of Egyptian Pharoahs (Watt & Breyer-Brandwijk, 1962). The tuber has been acclimatized in Ghana, Nigeria and Sierra Leone (Anon, 1992). The brown and yellow varieties of the tiger nuts can be found on the Nigerian market (Okafor et al., 2003). The yellow variety is highly desired because it is larger, more attractive, sweeter 15 University of Ghana http://ugspace.ug.edu.gh and juicier. Its milk also contains higher protein and lower fat levels, as well as less anti- nutritional factors; especially polyphenols (Consejo, 2006). In Ghana tiger nut is called “atadwe” by the “akans”, “atangme” by the “Gas”, “fie” by the “Ewes” and “nansaxa” by the “Dagombas” (Dokosi, 1998). The black and brown varieties are the main types cultivated in Ghana. Based on shape, colour and size of the nuts, Tetteh & Ofori (1998) identified seven types, designated as Kwahu I, II, III and IV and Fanti I, II and Ill. Anyidoho (2006) observed that the brown types were only planted in the forest areas of Kwahu in the Eastern Region while both the brown and the black types were planted in Bawjiase in the Central Region of Ghana. Tiger nuts are grown at places like Aduamoa in the Kwahu South District, Asukese, Odomasua, and Demso in the Afram Plains, Agona Kwanyaako, Bawjiase, and Elmina in the Central Region, and around Techiman in the Brong-Ahafo Region. Fante type of tiger nut Kwahu type of tiger nut Figure 1: Types of Tiger Nuts Grown in Ghana 16 University of Ghana http://ugspace.ug.edu.gh 2.2.1 Composition of Tiger Nuts The average nutritional figures for the tubers have been quoted as protein, 3.77 % - 6.72 %; crude fiber, 4.81 % - 8.91 % and sucrose, 19.02 % - 13.4 % by Coskuner et al., (2002) and Pascual et al., (2001) respectively. Excluding histidine, Bosch et al., (2005) has reported that tiger nuts contain higher essential amino acids (mg/g protein) than those recommended by the FAO/WHO for meeting the nutritional needs of adult. Tiger nuts have a good amount of some essential minerals like magnesium, 43µg/g; potassium, 265µg/g; zinc, 158µg/g and 20- 28 % of a yellowish non-drying oil (Fatoki et al., 1995). Dubois et al., (2007) have also reported that the main fatty acids present in tiger nut oil are 14:0 (0.2 %), 18:0 (3.2 %), 20:0 (0.4 %), 16:1 (0.3 %), 18:1 (72.6 %), 18:2 (8.9 %), and 18:3 (0.4 %), similar to olive and hazelnut oils. Ezeh et al., (2014) posited that the fatty acid profiles of tiger nuts, olive, avocado and hazel nut oils are similar. The fatty acid profile of tiger nuts is also highly stable due to its low content of tocopherol, phytosterol and polyunsaturated fatty acid. The phospholipids composition is also higher (3.1 % – 5.4 %) compared with soy bean oil. According to Ezeh et al., (2014), raw tiger nut contains 76.60 mg of iodine and 0.03 mg KOH/g oil of acid values; while roasted tiger nut oil was found to contain vanillin and to a smaller extent 2, 3‐dihydro‐ 3, 5‐dihydroxy‐6‐methyl‐4H‐pyran‐4‐one and 5‐ethylfurfural. These compounds in the roasted tiger nut oil contribute to the overall aroma of the oil. Tiger nut is also suitable for use as fuel in the coating industry due to its low viscosity. Tiger nut oil has a good nutritional value with the potential of being beneficial to its farmers, dealers and processors once it is exploited (Ezeh et al., 2014). 17 University of Ghana http://ugspace.ug.edu.gh 2.2.2 Health Benefits of Tiger Nuts Cyperus esculentus, which is high in dietary fibre is suitable for the management of many diseases including coronary heart disease, colon cancer, and gastrointestinal disorders. In addition, these tubers are said to be carminative, emmanogogue, aphrodisiac, diuretic, tonic, and stimulant (Adejuyitan, 2011). It has also been stated that tiger nut has been used in the treatment of heavy digestion, flatulence, diarrhoea (as it contains digestive enzymes like catalase, lipase and aminase) and excessive thirst. Tiger nut milk without sugar is recommended for diabetics due to the content of carbohydrates and Arginine (liberates the hormone that produces insulin) (Adejuyitan, 2011). The high non-soluble fiber content of the tiger nuts helps diabetics to regulate their sugar levels in the blood. Recent studies have demonstrated that the fiber does not elevate the sugar levels in the blood as carbohydrates do (Tiger Nut Traders S.L, 2010). The health advantages include decline of low density lipoprotein-cholesterol, which is suitable for sportsmen and women and people who want to lose weight. It is a measure for preventing cysts, prostate cancer, hernia, rectum deformation as it is known to promote urine production, and to prevent fibrosis as well as blockage at the tip of the fallopian tube (Bamishaiye, 2011). Nursing mothers are also advised to eat the soaked tubers as it will enhance breast milk production (El-Shenawey, 2012). The fibre content is higher than that of the oat bran, cabbage, carrot, plums and chia seeds and helps in the prevention of constipation. It also serves as an appetite suppressant, which will enable body weight management (Tiger Nuts Traders S.L, 2010). 18 University of Ghana http://ugspace.ug.edu.gh Cardiologists have also recommended eating non-saturated fats of vegetable fats. Tiger nut oil, having a similar lipid profile as olive oil, is considered as one of the healthiest oils (Tiger Nuts Traders S.L, 2010). Also, tiger nuts help to control blood pressure and prevent cancer and heart diseases. Tiger nut contains high amounts of arginine. This helps the body produce nitric oxide that leaves the blood vessels dilated and promotes normal blood flow (Tiger Nuts Traders S.L, 2010). Tiger nut helps to reduce the risk of heart diseases since it contains vitamin E and high amounts of oleic acids. The vitamin E protects the human body from the formation of free radicals which are harmful and can cause the death of the body cells (Tiger Nuts Traders S.L, 2010). Another health benefit of tiger nut is its natural source of magnesium. The human body obtains 13 % to 17 % of the daily recommended dose of magnesium when 100 g of tiger nut is consumed. This mineral remains active in the body and contributes to over 300 biochemical reactions in one’s body (Tiger Nuts Traders S.L, 2010). Consuming 25 g of tiger nuts provides the body with 139 mg of potassium, which is the same quantity a potato or an avocado will give; but exceeds the potassium levels of a banana. Potassium is known to promote proper functioning of cells and organs in the body. It also regulates the contractions of the muscles responsible for digestion (Tiger Nut Traders S.L, 2010). Proteins are important for the human body. Diverse studies have shown that tiger nut has an amount of protein which is 8 % higher than wholemeal wheat. Also, tiger nuts contain more amino acids than the World Health Organisation standards for proteins (The Tiger Nut Traders S.L, 2010). Finally, with a few tiger nuts, a healthy vegetable milk, which is lactose-free and rich in Vitamin C, Vitamin E and calcium, can be prepared in the kitchen. Consuming tiger nuts can 19 University of Ghana http://ugspace.ug.edu.gh cure diarrhoea and flatulence, help prevent colon cancer and heart attacks among others (Bamishaiye, 2011). 2.2.3 Uses of Tiger Nuts In Spain and Latin American countries, tiger nut is used in making the popular milk drink 'horchata de chufa' (Coskuner et al., 2000; Cortes et al., 2004). It is a characteristic product of Spain and of great monetary importance. Production is estimated at 40 - 55 million litres per year (Arranz et al., 1998). In the United States of America however, tiger nut has been used mainly to attract and feed water fowls, cranes and ducks (Mosquera et al., 1996). In Africa, tiger nuts are an important food crop for many people. They are eaten raw after washing or after it has been softened by soaking in water. It has also been reported to be roasted and chewed like roasted groundnuts or grated and used for the production of ice creams, biscuits or as a substitute for coffee (Abbiw, 1990; Dokosi, 1998). They are also used to produce non- alcoholic milky looking beverages (Sanful 2009; Ukwuru & Ogbodo, 2011). Common products derived from raw tiger nuts are skinned tiger nuts, peeled tiger nuts, tiger nut flour, tiger nut milk and tiger nut oil. The tiger nut milk may be made into cheese, yoghurt and ice cream, either as a pure product or composite product by combining with cow milk. Tiger nut flour may be combined with other ingredients to manufacture products such as tiger nut cheese cake (Ukwuru & Ogbodo, 2011). 20 University of Ghana http://ugspace.ug.edu.gh Figure 2 illustrates some products made from tigers: Skinned Tiger nuts Peeled Tiger nuts Tiger Nut Flour Tiger Nut Milk Tiger Nut cheesecake Tiger Nut Oil Figure 2: Examples of Products made with Tiger Nuts 2.2.3.1 Tiger Nut Oil To ensure that the tiger nut oil maintains all of its unique nutritious qualities, tiger nut oil extraction is done by a cold process. Over 4000 years ago, the Egyptians used tiger nut oil in preference to olive oil; as it is generally considered as a healthier substitute (Ukuru et al., 2011). The oil, golden brown in colour, has a rich nutty taste and can serve as a constituent of 21 University of Ghana http://ugspace.ug.edu.gh beauty products. The high oleic acid and low acidic nature of the oil is excellent for the skin. The oil can also be used for cooking (Ukuru et al., 2011). The colour and the nutty aroma make it ideal for frying and for use as bio-diesel. The oil is resistant to chemical decomposition at high temperature and the quantity needed for oil captivation is lower as compared with other oils (Lasekan & Abdulkarim, 2012). Tiger nut oil is very suitable for making cosmetics because of its high Vitamin E content which is an antioxidant and prevents ageing of the cells. Some of the cosmetics made from the tiger nut include bath milk and soap (Lasekan & Abdulkarim, 2012). The major benefit of Vitamin E in cosmetics is that it helps in the healing process of the skin. As Vitamin E is captured by the epidermis layer of the skin, it can be used for treating sun burn or in sunscreen to shield from the sun. Another benefit is that, it can be used in the treatment of scars, acne, and wrinkles as it speeds up cell regeneration. It also helps the skin to retain its natural moisture content (Lasekan & Abdulkarim, 2012). 2.2.3.2 Tiger Nut Flour Tiger nut flour has an exceptional taste, which is ideal for different uses such as biscuits, cakes, ‘‘Burkina’’ and other pastries (Ade-Omowaye, 2008). To produce flour out of tiger nuts, the nuts are cleaned, sorted to select the good ones, washed, oven dried and milled into flour. Tiger nut flour is a rich source of oil and some valuable mineral elements such as iron and calcium, which are essential for body growth and development. It also contains a moderate amount of protein (Oladele & Aina, 2007). According to Oladele and Aina (2007), the low bulk density, setback and breakdown viscosities displayed by tiger nut flour enables its use without fear of retrogradation. 22 University of Ghana http://ugspace.ug.edu.gh 2.2.3.3 Tiger Nut Milk The tiger nuts are pressed for its milk and used to make a beverage known as “horchata de chufa” in Spain or “kunnu aya” in Northern Nigeria (Belewu & Abodunrin, 2006). Tiger nut can be processed into varieties of tiger nut milk products like natural tiger nut milk, pasteurized tiger nut milk, sterilized tiger nut milk, ultrahigh temperature tiger nut milk, condensed tiger nut milk and concentrated tiger nut milk. Tiger nut milk can be used by people having milk allergies such as galactosemia, and lactose intolerance (Ukwunu & Ogbono, 2011). Yoghurts are also produced from tiger nut milk through a fermentation process. It can also be made into pudding for dessert. Tiger nut milk is also very popular in some South American countries (Cortes et al., 2004; Corrales et al., 2012). The refreshing non-alcoholic beverage of milky appearance is normally produced from dried nuts which are ground and extracted with water (Kay, 1987). The milk beverage has a pH in the range 6.3 - 6.8 and is rich in starch (Cortes et al., 2004, Belewu & Belewu, 2007). Heating the tiger nut milk beverage above 72 °C therefore results in changes in the physical and organoleptic characteristics due to the gellification of the starch (Cortes et al., 2004). The physical, chemical and sensory characteristics of the tiger nut milk beverage have been found to depend on factors, such as the variety of tuber and procedure for beverage production (Belewu & Belewu, 2007; Navarro et al., 1984). The nutritional value of a typical fresh tiger nut milk with 10 % sugar added has been reported as 3 % fat, 1 % protein, 3 % starch, and other carbohydrates making up 20 % (De Venanzi, 1991). The composition of fatty acids in the drink have been found to be comparable with that of olive oil, with oleic acid constituting about 75 % while palmitic and the other unsaturated fatty acids mainly linoleic and linolenic comprise 12.5 % and 10 % respectively (Belewu & Belewu, 2007). In a study on the composition of tiger nut milk by Cortes et al., 23 University of Ghana http://ugspace.ug.edu.gh (2004) arginine, glutamic acid and aspartic acids were the major acids recorded. The following essential amino acids; isoleucine, leucine, lysine, methionine, phenylanine, threonine, tryptophan and valine were also found to be in appreciable quantities. The flavour of horchata de chufa has been described by researchers as nutty, pleasant and refreshing, chalky coconut, and vanilla-like (Reid et al., 1972; Barber, 1981; Linssen et al., 1989; De Venanzi, 1991). 2.3 Other Vegetable Milk The use of plant materials in the production of dairy-like milk is one possibility that has been identified as a means of meeting the ever increasing demand for proteins, vitamins, minerals, carbohydrates and health beneficial ingredients that would have been derived from consuming dairy milk (Edwards, 1998). Non-dairy or vegetable milk are the general names of plant based milk, which are obtained by water extraction of plant materials such as oil seeds and 41 legumes with a colour unique to every plant material (Edwards, 1998). Vegetable milks are colloidal emulsions and suspensions which have particles or droplets with at least one linear dimension in the size range of 1 nm to about 1 mm (Dickinson, 1992). The composition of the emulsion is usually the small fat or oil droplets, stabilized with surface- active agents such as proteins and lipids. The suspensions, however, are the undissolved solid particles, such as protein, starch, fiber and other cellular material, which are present in the aqueous solution (Dickinson & Stainsby, 1988). While the insoluble particles in the solution can aggregate and form sediments, the less stable droplets in emulsion can also merge and increase in size over time (Dickinson & Stainsby, 1988). Non-dairy milk has attracted a lot of interest because of its potential as a low cost and healthy alternative to cow milk (Wong, 2013; Diarra et al., 2005). In comparison to cow milk, they have no significant quantities of 24 University of Ghana http://ugspace.ug.edu.gh cholesterol or lactose, which makes them an attractive alternative for people conscious of their health and/or diet, vegetarians, and those who are lactose intolerant (Benward & Benward, 2000). The intensification in the demand for non-dairy milk products by consumers has led to the development of alternatives to animal milk products such as infant formulas (Benward & Benward, 2000); low sugar and low calorie milks for dietetic and diabetic purposes (Demirag et al., 1999); and non-dairy fermented products (Martensson et al., 2000; Shirai et al., 1992). Vegetable milk has been used for a long time in many societies, both as a standard drink, and as an alternative to dairy milk. Common examples include soy milk, almond milk, rice milk and coconut milk (Purdy, 2017). This kind of milk contains no lactose or cholesterol, and is typically fortified with calcium and vitamins, particularly vitamin B12. However, there are differences in their protein content depending on the plant source (Wong, 2013). In the United States, soy milk was long the most common non-dairy milk, at the same time, around 2010, almond milk became quite well known, and eventually outperformed soy milk in 2013 (Wong, 2013). Other common vegetable milk in the US are rice and coconut milk. Vegetable-based milk make up 9.3 % of the aggregate milk market. In Europe soy and oat milk are prominent (Purdy, 2017). There is likewise hemp milk, cashew nut milk, hazelnut milk, and milk from peas and lupin. Vegetable milks are utilized in the production of ice- cream, vegetable cream and yoghurt (Purdy, 2017). 2.4 Composite Milk According to the European Commission, “Composite Products” are defined in Article 2(a) of Commission Decision 2007/275/EC as “a foodstuff intended for human consumption that 25 University of Ghana http://ugspace.ug.edu.gh contains both processed products of animal origin and products of plant origin and includes those where the processing of primary product is an integral part of the production of the final product”. For this guidance, the composite products of animal origin must be processed before being mixed with that of plant origin. ‘Dairy products’ means processed products obtained from the processing of raw milk or from the further dispensation of such processed products (United Kingdom Food Standards Agency, 2017). Milk product is a product obtained by any processing of milk, which may contain food additives, and other ingredients functionally necessary for the processing (Purdy, 2017). Composite milk product is defined as “a product of which the milk, milk products or milk constituents are an important part in terms of amount in the final product, as consumed, provided that the constituents not derived from milk are not intended to take the place in part or in whole of any milk constituent” (Codex Alimentarius Standard 206. 2014). From the above definition, milk from non-dairy sources such as tiger nut milk does not by itself constitute composite milk and will be termed as such only when the tiger nut milk is mixed with processed milk of animal origin. Composite milk may also consist of a combination of milk from different animal sources (cow, sheep, goat), different plant sources or both animal and plant sources in varying proportions (Wong, 2013). This is usually done for different purposes depending on the intended use. Some composite milk is developed to reduce lactose intolerance and others are formulated to suit product specifications or achieve a desired nutritional or physicochemical specification. Others are produced to provide several food options for the consumer (Wong, 2013). 26 University of Ghana http://ugspace.ug.edu.gh 2.4.1 Products from Composite Milk Figure 3 illustrates the concept of composite dairy products and shows the various combinations of milk sources and non-milk sources that may be possible. The composite milk product ‘‘Burkina’’ covered by this study comprises processed cow milk and tiger nut milk as the milk sources and millet as the non-dairy source. The two milk sources combined constitute composite milk as per the definition in section 2.4 above. Cheese is a dairy product made from milk by coagulating the milk protein (casein). It is made up of milk proteins and fat. Amid generation, the milk is fermented, and a catalyst (rennet) is added to facilitate coagulation. The solids are separated and squeezed to form the product (Tijani, 2014). Herbs, flavours or wood smoke might be utilized as flavour enhancing agents. The yellow to red shade of numerous cheeses are made by including annatto. Different food items, such as dark pepper, garlic and cranberries, might be added to a few cheeses to produce a desired flavour (Fankhauser, 2007). Other products made with composite milk include Ice cream, Yoghurt, and Flavoured Milk (Fankhauser, 2007). Figure 3: Concept of Composite Dairy Foods including Milk Composites Source: https://www.slideshare.net/oshnic/composite-dairy-foods/1 27 University of Ghana http://ugspace.ug.edu.gh 2.5 Microbiology of Milk and Dairy Products The constituents of milk, water, fats, proteins and vitamins allow for the growth of a variety of bacteria, especially psychotropic bacteria that are able to grow under cold conditions (Speake, 2015). Raw milk, pasteurized milk, cheese, and other dairy products support different and diverse groups of microorganisms which cause product spoilage. Light can also contribute to the spoiling of dairy products (Speake, 2015). There are many techniques, however, such as pasteurization and special packaging, which are used to protect these dairy products from adverse effects of microbial growth and light (Speake, 2015). Farmers, dairy processors, and consumers use many methods to measure the degree of spoilage and gauge milk quality. Preventing microbial growth and extending shelf life can alleviate cost for producers, retailers and consumers, but can also limit the environmental impact of dairy production and consumption (Lu & Wang, 2017). Spoilage microorganisms include aerobic psychotropic gram-negative bacteria, yeasts, molds, hetero-fermentative lactobacilli, and spore-forming bacteria. Psychrotrophic bacteria can produce large amounts of extracellular hydrolytic enzymes, and the extent of recontamination of pasteurized fluid milk products with these bacteria is a major determinant of their shelf life (Lu & Wang, 2017). Fungal spoilage by dairy foods is manifested by the presence of a wide variety of metabolic by- products, causing off-odours and flavours, in addition to visible changes in colour or texture (Ledenbach & Marshall, 2009). 2.6 Sensory Evaluation of Milk and Dairy Products Alvarez (2015) suggest that descriptive sensory evaluation methods which are used to evaluate the characteristics of milk and dairy products to monitor processing conditions and determine product quality are a valuable tool, especially for industry, because they are fast, 28 University of Ghana http://ugspace.ug.edu.gh practical, and simple. They further suggest that the sensory evaluation methods of dairy products are evolving like other techniques (Alvarez, 2015). Sensory quality is the ultimate measure of product quality and success. Sensory analysis comprises a variety of powerful and sensitive tools to measure human responses to foods and other products. Selection of the appropriate test, test conditions, and data analysis, result in the generation of reproducible, powerful, and relevant results (Drake, 2010). Appropriate application of these tests enables specific product and consumer insights and the interpretation of volatile compound analyses to flavour perception (Drake, 2010). 2.7 Packaging of Milk and Dairy Products The type of packaging material used for dairy products is of critical importance because of its impact on quality, safety, cost, and marketing of dairy to consumers. Recent interest has shifted towards novel applications such as smart or intelligent packaging, modified atmosphere and active packaging, and sustainability (Karaman et al., 2015). The addition of shelf life extending compounds to packaging films rather than directly to food can be used to provide continued inhibition for product stabilization. For further processed foods with greater than one-week shelf life, active packaging can provide an added level of protection downstream in the distribution cycle (Dawson, 2011). Direct addition of antimicrobials for instance, will have a strong initial effect but will have little effect later in the distribution cycle since the antimicrobial will react with food components or be absorbed into the food bulk. For non-fluid foods, the deteriorative reactions occur primarily at the food surface. Thus, less antimicrobial compounds will be needed when used in the package since the compound will be released at the location of need, the food surface (Dawson, 2011). 29 University of Ghana http://ugspace.ug.edu.gh According to Bertelsen (2012), prior to commercial use of bio-based primary packaging materials several concerns must be addressed. First of all, the bio-based material must remain stable during storage of the food products, maintaining the mechanical and/or barrier properties. Ideally, the materials should biodegrade efficiently on disposal. Thus, environmental conditions conducive to biodegradation must be avoided during storage, whereas optimal conditions for biodegradation must exist after discarding (Dawson, 2011). In order to reduce deterioration of the food products it is also important that the bio-based packaging material meets the requirements of the individual food products (Bertelsen, 2012) 30 University of Ghana http://ugspace.ug.edu.gh CHAPTER THREE 3.0 METHODOLOGY 3.1 MATERIALS 3.1.1 Ingredients The ingredients used included milk powder, tiger nuts, pearl millet and sugar. These were purchased from a local market in Accra. 3.1.2 Tools, Equipment and Chemicals Some examples of tools, equipment and chemicals used in the “Burkina” production include; a home food processor, stainless steel food containers, sieves, sensory cups, spoons and Milton sterilizing tablets which were purchased from local vendors. 3.2 METHODS 3.2.1 Preparation of Tiger Nuts for Milk Extraction 3.2.1.1 Cleaning and Soaking of Tiger Nuts The tiger nuts were thoroughly washed under running water to remove dirt and carefully hand-sorted to separate wholesome tiger nuts from unwholesome ones and other unwanted material like stones. Tiger nuts with bruises and those that where soft, mouldy, had holes in them or were discoloured, were discarded. This was done to reduce microbial load, remove bad tiger nuts and ensure product quality and safety (Nyarko-Mensah et al., 2015). 31 University of Ghana http://ugspace.ug.edu.gh 3.2.1.2 Tiger Nut Treatment The soaked tiger nuts were washed again, sterilised with Milton solution for 15 minutes (one Milton Tablet per 5 L of water, per manufacturer’s instruction), blanched in boiling water (100 ˚C) for 5 minutes and allowed to cool. This was done to further reduce the microbial load on the tiger nuts. Blanching tiger nut tubers helps to improve the colour and enhance the flavour of the milk extract (Frimpong, 2016). It also reduces aggregation and settling of the biological polymers of the milk extract; thereby improving its colloidal stabilisation (Nyarko- Mensah et al., 2015). 3.2.1.3 Milling of Tiger Nuts and Extraction of Tiger Nut Milk The sterilised tiger nut tubers were placed in an H-Kitchen Universal Fritter Model QS513 and milled at high speed for 10 minutes. Milled tiger nut tubers (400 g) were weighed and 400 mL of purified water was added to the tiger nuts. The tiger nut slurry obtained was filtered through a 200 µm mesh nut milk bag (30.48 cm x 30.48 cm) to obtain tiger nut milk. The filtrate was filtered again with a 200 µm mesh nut milk bag to obtain a tiger nut milk colloid (Nyarko-Mensah et al., 2015). The filtered tiger nut milk was heated to a temperature of 56 ˚C for 15 seconds to reduce microbial load and enhance filtrate flavour and taste (Figure 4). The process for milling the tiger nuts and extracting the tiger nut milk is outlined in Figure 4. 32 University of Ghana http://ugspace.ug.edu.gh Selected Whole Tiger Nuts Sorting & Washing Soaking (18 hrs) Washing Wet milling (10 min at high speed) Water (1:1) Slurrying () Filtering (200 µm N ut Milk B a g) () Pasteurisatio n (56 ˚C for 15 seconds) Tiger Nut Milk Extract Figure 4: Flow Chart Showing Tiger Nut Milk Extraction Process 3.2.2 Pearl Millet Treatment and Agglomeration The Pearl millet were sorted to remove unwanted material, washed under clean running water and soaked for 24 hours to remove anti-nutrients and aid digestion. The pearl millet was washed again and wet milled with a hand mill into a coarse flour which was exposed to air to ferment for 2 hours. Water was added to the pearl millet flour (10 mL : 100 g) and agglomerated by hand in a 1 mm mesh sieve. The agglomerate was then steamed for 30 33 University of Ghana http://ugspace.ug.edu.gh minutes and allowed to cool (Figure 5). The production of Pearl millet agglomerates is outlined in Figure 5. Pearl Millet Sorting Washing Soaking (24hrs) Washing Coarse Wet Milling Spontaneous Fermentation (2 hrs) Salt & Sugar Agglomeration (1 mm mesh ) Steaming (30 min) Cooling Fermented Pearl Millet Agglomerates Figure 5: Flow Chart Showing the Production of Fermented Pearl Millet Agglomerates 34 University of Ghana http://ugspace.ug.edu.gh 3.2.3 Production of ‘‘Burkina’’ made with Cow’s Milk ‘‘Burkina’’ was produced using the method of Otwe (2015) with modifications (which are described below). Three different samples of “Burkina” were prepared using whole milk powder, semi-skimmed milk powder and skimmed milk respectively. Each one of these was classified as a homogenous mixture. Milk powder [whole or semi-skimmed (234 g)] was added to 900 mL of purified water to form reconstituted whole and semi-skimmed milk respectively. ‘‘Burkina’’ from skimmed milk was prepared using Ultra-High Temperature (UHT) pasteurised skimmed milk. The milk (whole, semi-skimmed and skimmed) were pasteurised at 72 ˚C, cooled to 43 ˚C and inoculated with 90 g of culture. The culture was obtained from a commercial “Burkina” product. The inoculated milk (whole, semi-skimmed and skimmed) were incubated at 35 ˚C for 9 hours to form ‘nunu’ milk which varied in thickness and colour (based on the fat content of the milk). Fermented products were homogenized with a 20 µm mesh sieve to obtain a fine consistency. Fermented Pearl Millet agglomerates (20 g) and sugar (8.5 g) were added to each of the ‘nunu’ milk samples. The product was kept refrigerated until used. 3.2.4 Preparation of ‘‘Burkina’’ made with Composite (Cow and Tiger Nut) Milk. “Burkina” made with composite milk was made using the method of Otwe (2015) with modifications (which are described below). Milk powder [whole or semi-skimmed (140.4 g)] was added to 540 mL of purified water and stirred to obtain 600 mL of reconstituted whole or semi-skimmed milk. The skimmed milk ‘‘Burkina’’ product was made using Ultra-High Temperature (UHT) pasteurised skimmed milk. The reconstituted whole milk, reconstituted semi-skimmed milk or UHT skimmed milk were pasteurised at 72 ˚C for 15 seconds. Tiger 35 University of Ghana http://ugspace.ug.edu.gh nut milk extract was prepared as indicated in figure 4 (refer to section 3.2.1.3). Composite milk was prepared by adding 400 mL (40 %) of tiger nut filtrate to 600 mL (60 %) of whole, semi-skimmed and skimmed milk. The composite milk was inoculated with 90 g of the commercial ‘‘Burkina’’ culture and incubated at 35 ˚C for 9 hours to form ‘nunu’ milk. The ‘nunu’ milk obtained varied in thickness and colour and was homogenised with a 20 µm mesh sieve to obtain a finer consistency. After homogenisation, 20 g of millet agglomerates (see section 3.2.2) and 8.5 g of sugar were added to the composite milk, stirred and kept refrigerated until analysed for colour, proximate and mineral composition, microbiology and sensory attributes. 3.2.5 Packaging and storage of “Burkina” samples The ‘‘Burkina’’ samples made with or without tiger nut were packaged in 330 mL polyethylene terephthalate (PET) bottles, sealed and refrigerated at 6 ˚C until analysed. 3.3 Colour Determination of ‘‘Burkina’’ samples The difference in colour of the homogenous and composite ‘‘Burkina’’ samples were measured using a modified method of Yadav et al. (2012). Colour of the samples were determined with a Hunter Lab Colour Analyzer (CR310 Chromameter, Konica Minolta, Tokyo, Japan 76981007) to obtain the L (lightness), a (redness) and b (yellowness) values. ‘L’ ranges from 0 (black) to 100 (white) and both ‘a’ and ‘b’ values range from negative (-) to positive (+). Ten millilitres of each sample was taken and evenly spread in a petri dish. The colour analyser was calibrated with a standard white tile background. The standard values for the calibrations were as follows: L = 97.63, a = -0.48, b = + 2.12 36 University of Ghana http://ugspace.ug.edu.gh The probe was placed on the petri dish containing the “Burkina” sample to obtain the L.a.b. values. ∆ E value (size of total colour difference) was determined using the equation below: ∆ E = √ (∆ L) 2 + (∆ a) 2 + (∆ b) 2 (Morrison & Laignet, 1983) Where ∆ L = Sample L value – Standard value, ∆ a = Sample a value – Standard value and ∆ b = Sample b value – Standard value. The ∆ E value however does not give information on how the colours differ. 3.4 Determination of pH for ‘‘Burkina’’ Samples ‘‘Burkina’’ pH was determined according to the method of Chinma et al. (2010) with modifications in the volume of sample used (30 ml instead of 50 ml). Standard buffer solutions of pH 4, 7 and 10 were used to calibrate the Mettler Toledo Seven Compact pH meter. “Burkina” samples (30 mL per sample) were measured and poured aseptically into 50 mL beakers. The pH meter was dipped into the beaker containing the samples and readings were recorded. Recalibration of the pH meter was done after each reading was taken to ensure accuracy of results. 3.5 Proximate and Mineral Composition of the Homogenous and Composite Blends of ‘‘Burkina’’ The protein, ash, moisture and fat content of the ‘‘Burkina’’ samples were determined using the Kjeldahl, mojonnier, dry ashing, air-oven, and dye-binding assay methods respectively. Crude carbohydrate was determined from the difference between the sum of the other 37 University of Ghana http://ugspace.ug.edu.gh components and 100 %. The other minerals (phosphorus, magnesium, potassium and sodium), were determined using Atomic Absorption Spectrophotometry (AAS). 3.5.1 Protein Determination. To determine the protein content of the ‘‘Burkina’’ samples, the following analyses were done using the Association of Analytical Communities (AOAC) 991.20 (2005) method: “Burkina” sample (1 g) without moisture was digested with 20 mL of concentrated sulphuric acid (H2SO4) and heated on a digester until the solution changed from black to greenish blue; indicating the end point of the reaction. This reaction was enhanced with a catalyst (500 g of potassium sulphate, 8 g of copper sulphate and 8 g of selenium powder). Ammonium sulphate was obtained from this reaction. Protein distillation and titration involved the separation of the ammonium salt from the concentrated H2SO4. In strong alkaline solution, gaseous ammonia is purified and trapped in standard acid solution. The reagents used were 0.01 N hydrochloric acid (HCl) and 40 % sodium hydroxide (NaOH). Tashiro Indicator (1 g Methyl red + 0.5g Methylene blue dissolved in 200 mL of 70 % ethanol) was used to determine the end point of titration. To begin the process, purified water was used to clean the distillation apparatus for a few minutes. The Kjedahl extract was then diluted with 30 ml purified water. Boric acid 2 % (5 mL) was poured into a conical flask and 2 drops of Tashiro indicator was added to it and placed under a condenser (the tip of the condenser dipped into the receiving acid in order to avoid any ammonia loss). The digestion tube was attached to the distilling end. A 5 mL aliquot of the digested sample was measured and 5 mL of 40 % NaOH was added from an automatic burette. Distillation continued for about 4 minutes; producing 40 mL of distillate. The conical flask was lowered and the tip of the condenser was washed into the conical flask 38 University of Ghana http://ugspace.ug.edu.gh for 1 minute. The distillate was removed and titrated with 0.01 N HCl to a green end point. The percentage nitrogen (% N) was calculated as: % N = ( B - T) X 0.01N HCl X Vol Ext X 100 X 14/W X Aliquot X 1,000 ) % N = ( 0 - T) X 0.01N HCl X 40 mL X 100% X 14/1,000 mg X 5 mL X 1,000 ) Where: B is the titration value for blank T is the sample titration value. W is the weight of “Burkina” sample in milligram. To convert to crude Protein, the % N was multiplied by 6.25. 3.5.2 Ash Determination In determining the ash content of the samples, AOAC 945.46 (2005) method was used. An empty crucible was weighed and the value x recorded. “Burkina” sample (10 g) was placed in the crucible and the weight of the crucible and sample y was recorded. The crucible was then placed in a furnace for 24 hours at 600 ˚C. The weight of the crucible and ashed sample m was determined after 24 hours. Percentage ash was calculated using the formula below: 𝑚−𝑥 New % ash = × 100 𝑦−𝑥 3.5.3 Moisture Determination AOAC (2005) method was adopted for this analysis. The weight of an empty aluminium dish x was determined. “Burkina” sample (10 g) was weighed and placed in the dish and the weight y recorded. The aluminium dish containing the “Burkina” sample was placed in an 39 University of Ghana http://ugspace.ug.edu.gh oven at 105 ˚C for 24 hours then cooled at ambient temperature. Then the weight of the aluminium dish with “Burkina” sample was determined and the value m recorded. Percentage moisture was calculated using the formula below: 𝑦−𝑚 New % moisture = × 100 𝑦−𝑥 3.5.4 Fat Determination AOAC 989.05 (2005) method was used to determine fat content. An empty thimble was weighed and the value recorded as a before it was filled with 10 g of the ‘‘Burkina’’ sample and the weight recorded as b. The thimble was covered with cotton, and weighed before extraction and the value recorded as c. The thimble was then suspended in the chamber of an extractor containing petroleum sprint at 50 ˚C. The extraction was done for an hour before the thimble was brought out and dried at ambient temperature. The weight of the dried sample after extraction was recorded as d. Percentage fat was calculated using the formula below: 𝑐−𝑑 % fat = * 100 𝑏−𝑎 3.5.5 Carbohydrate Determination The percentage of protein, ash and fat were summed up and subtracted from the difference between a hundred percent and percentage moisture as indicated by Harold et al. (1981). Percentage carbohydrate was calculated using the formula below: % Carbohydrate = (100 - % moisture) – (% Protein + % Ash + % Fat) 40 University of Ghana http://ugspace.ug.edu.gh 3.6 Mineral Composition of the Homogenous and Composite Blends of ‘‘Burkina’’ The mineral content of the various ‘‘Burkina’’ samples was determined using the Atomic Absorption Spectrophotometry method. Samples were analyzed in solution form. To analyze for a given element, a lamp was chosen that produced a wavelength of light that is absorbed by the element being analysed for. Sample solutions were aspirated into the flame. If any ions of the given element were present in the flame, they would absorb light produced by the lamp before it reached the detector. The amount of light absorbed depended on the amount of the element present in the sample. Absorbance values for unknown samples were compared to calibration curves prepared by running known samples. 3.7 Microbiological Analyses of “Burkina” samples Microbiological analyses of the samples were done using the AOAC International (2002) method. Petri dishes used for the analyses were all autoclaved for an hour before they were used. The media used were Plate Count Agar (PCA) for total counts, Maconkey Agar (MA) for coliform counts, Blood Agar (BA) for Staphylococcus aureus counts, Oxytetracycline Glucose Yeast Extract (OGY) for yeast and mold counts, Xylose Lysine Deoxycholate Agar (XLD) for salmonella counts and Eosin Methylene Blue Agar (EMB) for E.coli counts. Each one of them had specific weights measured and diluted with distilled water according to the manufacturer’s instructions. The diluted media were heated on a Bunsen burner and placed in a water bath at 45 ˚C to prevent them from setting. Peptone (7.5 g) was diluted with 500 mL of water to form an isotonic peptone water solution; of which 90 mL was pipetted into smaller volumetric flasks and 9 mL into several test tubes. The removable pipette tips, the test tubes and flasks containing the peptone water were autoclaved for an hour as well. To avoid 41 University of Ghana http://ugspace.ug.edu.gh contamination during analysis, the outer layer of the container with the “Burkina” sample was first cleaned with cotton soaked in alcohol before opening it. “Burkina” sample (10 g) was then weighed into a stomacher bag and 90 mL of peptone water added and homogenized with a stomacher blender. Appropriate six-fold serial dilutions were prepared. The pour plate method was used. With this, a bacterial solution was poured into an empty plate to be inoculated. Melted nutrient agar was poured into the empty plate and swirled for uniformity. 3.8 Sensory Evaluation 3.8.1 Focus Group Discussion A Focus Group Discussion (FGD) was done with 41 panelists at the Department of Family and Consumer Sciences Product Development Laboratory. The FGD was a qualitative study that was geared towards understanding the desirability of ‘‘Burkina’’ and consumers’ perception on drinking ‘‘Burkina’’ made with flavoured milk. The discussion also focused on the packaging and safety of ‘‘Burkina’’. The FGD was done with an interview guide. The 41 panelists were split into six different Focus Groups and asked to sign an informed consent form before the discussions began. Each Focus Group consisted of a minimum of 6 participants and a maximum of 8 participants. The participants were informed that the discussion would be audio recorded and were given an opportunity to ask for clarification before their session began. 3.8.2 Consumer Acceptance Test A consumer acceptance test was done with 43 untrained panelists who were either consumers or non-consumers of ‘‘Burkina’’. A preference test was used to measure factors such as the 42 University of Ghana http://ugspace.ug.edu.gh appearance, colour, aroma, taste, mouthfeel and flavour. The test consisted of rating each ‘‘Burkina’’ product, based on the factors above, using a 9-point Hedonic scale. Panelists were presented with 50 mL ‘‘Burkina’’ samples made with whole milk, semi-skimmed or skimmed milk and Tiger nut composite versions of these milk types. The samples were coded with random 3 digit codes and served simultaneously. Instructions were given to the panelists to cleanse their palate with water before and after assessing each sample. The evaluations were conducted in a well-lit room with white fluorescent lights. 3.9 Study Design and Data Analyses A two factor experimental design (2 3 ) was used for this study. With the exception of Sensory Evaluation, all experiments were carried out in triplicates. Analysis of Variance (ANOVA) was performed with significance of means tested at the 95 % confidence limit using the Statistical Package for Social Sciences (SPSS) version 24.0 (Softonic International S.A). Illustrations with tables were done using Microsoft Office Excel 2013. Thematic analysis of consumer focus group discussion was carried out using the Attride-Stirling 2001 method, with the aid of ATLAS.ti.7. 43 University of Ghana http://ugspace.ug.edu.gh CHAPTER FOUR 4.0 RESULTS AND DISCUSSION 4.1 Proximate Composition of ‘‘Burkina’’ Samples The proximate composition of the ‘‘Burkina’’ samples determined included moisture, ash, protein, fat and carbohydrate. The values were reported as percentage dry-matter basis except for moisture content values. Table 2 shows the proximate composition of the ‘‘Burkina’’ samples. Table 2: Proximate Composition of “Burkina” samples Sample Moisture Ash (%) Protein (%) Fat (%) Carbohydrate (%) (%) FCM 80.18 ± 0.39a 3.81 ± 0.42b 5.85 ± 0.02c 2.74 ± 0.11c 7.42 ± 0.23a FCMT 75.42 ± 0.41b 4.91 ± 0.03a 7.91 ± 0.18a 4.04 ± 0.14a 7.72 ± 0.19a SSM 84.89 ± 0.62a 3.45 ± 0.09b 4.61 ± 0.19d 1.31 ± 0.09d 5.74 ± 0.18b SSMT 78.03 ± 0.81b 4.46 ± 0.14a 6.46 ± 0.20b 3.44 ± 0.08b 7.61 ± 0.15a SM 86.29 ± 0.69a 3.11 ± 0.17b 4.04 ± 0.13d 1.04 ± 0.12d 5.52 ± 0.27b SMT 79.71 ± 0.69b 4.11 ± 0.11a 6.13 ± 0.15b 3.03 ± 0.13b 7.02 ± 0.22a FCM (Full Cream Milk), SSM (Semi-Skimmed Milk) and SM (Skimmed Milk) are homogenous ‘‘Burkina’’ samples while FCMT (Full Cream Milk with Tiger Nut), SSMT (Semi-Skimmed Milk with Tiger Nut) and SMT (Skimmed Milk with Tiger Nuts) are ‘‘Burkina’’ samples containing 40 % tiger nut milk. Values are means and standard deviations of triplicate analysis. The values were reported as % dry matter, except for moisture content values. Means in the same column with the same letter are not significantly different; p ≤ 0.05. 44 University of Ghana http://ugspace.ug.edu.gh 4.1.1 Moisture Content Moisture content of the ‘‘Burkina’’ samples was determined as the mass of water in a given mass of ‘‘Burkina’’ samples removed by evaporation. The moisture content of the samples ranged from 75.42 % - 86.29 %. ‘‘Burkina’’ samples with tiger nuts, [Full Cream Milk with Tiger Nuts (FCMT), Semi-Skimmed Milk with Tiger Nuts (SSMT) and Skimmed Milk with Tiger Nuts (SMT)] had lower moisture levels (p ≤ 0.05) compared with ‘‘Burkina’’ samples without Tiger Nuts [Full Cream Milk (FCM), Semi-Skimmed Milk (SSM) and Skimmed Milk (SM)] (Table 2). There was no effect of milkfat levels [Full cream (4 %), Semi- Skimmed (2 %) and Skimmed (0 %)] on ‘‘Burkina’’ moisture levels. 4.1.2 Fat Content The incorporation of tiger nut milk into the ‘‘Burkina’’ samples led to an increase in ‘‘Burkina’’ fat levels (p ≤ 0.05). ‘‘Burkina’’ samples with tiger nuts (FCMT, SSMT and SMT) had higher fat levels (p ≤ 0.05) compared with ‘‘Burkina’’ samples without tiger nuts (FCM, SSM and SM). It was observed from Table 2 that the incorporation of 40 % tiger nut milk into the “Burkina” samples increased the fat content of the product. This can be attributed to the fact that tiger nut is rich in fatty acids (Dubois et al., 2007; Ezeh et al., 2014). The fat levels were within the range 1.4 % – 4.5 % as reported by Chinedu et al., (2012). The fat content of the samples may be a useful indicator of their flavour and may influence the processing, packaging and storage of the ‘‘Burkina’’ products (Chinedu et al., 2012). 45 University of Ghana http://ugspace.ug.edu.gh 4.1.3 Carbohydrate and Protein Content The carbohydrate content of ‘‘Burkina’’ samples was estimated by difference after the sum of all the other proximate analysis components (Table 2) had been subtracted from 100 %. ‘‘Burkina’’ samples with tiger nuts had higher carbohydrate contents (p ≤ 0.05) compared with ‘‘Burkina’’ samples without tiger nuts. Carbohydrate content of ‘‘Burkina’’ without tiger nuts made from semi-skimmed and skimmed milk were lower than in the full cream version without tiger nuts (p ≤ 0.05). The carbohydrate content of the samples ranged from 5.52 (SM) – 7.72 % (SST) and are within the range reported by Frimpong (2016). Incorporation of tiger nuts into ‘‘Burkina’’ resulted in higher protein levels. Protein levels were higher in ‘‘Burkina’’ made with tiger nuts (p ≤ 0.05) compared with ‘‘Burkina’’ made without tiger nuts. ‘‘Burkina’’ made with full cream milk had higher protein levels (p ≤ 0.05) than ‘‘Burkina’’ made with skimmed and semi-skimmed milk (Table 2). Higher carbohydrate and protein levels may make tiger nuts useful for food fortification programs (Grosso et al., 2008). Carbohydrates contribute to the taste and flavour of the products and help in the development of the characteristic colour of the products (Grosso et al., 2008). 4.1.4 Total Ash Content The total ash was determined by the combustion of the ‘‘Burkina’’ samples (with and without tiger nuts) and measured as the mineral content of the milk samples (Blitz et al., 2009). The total ash content determined for the six samples differed significantly (p ≤ 0.05) as observed in Table 2. Incorporation of tiger nuts into ‘‘Burkina’’ resulted in higher ash levels (p ≤ 0.05). All ‘‘Burkina’’ samples with tiger nuts (FCMT, SSMT and SMT) had higher ash levels (p ≤ 0.05) than ‘‘Burkina’’ samples without tiger nuts (FCM, SSM and SM). Tiger nuts are 46 University of Ghana http://ugspace.ug.edu.gh high in minerals such as magnesium, potassium and phosphorous (Abraham, 2013) which would contribute to the high ash levels. There was no effect of milk fat levels on the ash content of ‘‘Burkina’’. Minerals are important in food for their nutritional and physiological roles. However, some of them (such as magnesium and zinc) catalyse oxidative activity in foods containing fat and often cause undesirable colour changes, oxidize ascorbic acid and create off-flavours and taste defects through fat oxidization in foods such as milk products (Blitz et al., 2009). 4.2 Mineral Composition of “Burkina” Samples The mineral composition determined included potassium, sodium, magnesium, phosphorus and calcium. Table 3 shows the results obtained from the analyses. It is observed in Table 3 that the mineral content of the ‘‘Burkina’’ samples were high even though there were significant differences across all the minerals examined (p ≤ 0.05). This is not surprising as both cow and tiger nut milk are well known for their high mineral content (Sanful, 2009). The variations in the minerals examined can be attributed to several factors such as the incorporation of tiger nut milk to some of the samples. Tiger nut milk has high mineral content, so it can be observed from Table 3 that the tiger nut composite milk samples (FCMT, SSMT, and SMT) had relatively higher mineral values with the exception of calcium. Milk is known to be rich in calcium. It is therefore not surprising that the ‘‘Burkina’’ samples without tiger nut had higher values than those made with composite milk. Minerals are important in food for their nutritional and physiological roles. However, they can be a disadvantage as they can cause off flavours and colours when there is poor handling or storage (Blitz et al., 2009). 47 University of Ghana http://ugspace.ug.edu.gh Table 3: Mineral Composition of “Burkina” Samples Sample Potassium Sodium Magnesium Phosphorus Calcium (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) FCM 18.39 ± 0.39b 2.22 ± 0.06a 1.786 ± 0.00e 12.20 ± 0.28d 38.40 ± 0.91a FCMT 21.35 ± 0.13a 1.99 ± 0.01b 4.69 ± 0.25b 12.63 ± 0.17d 24.50 ± 5.10b SSM 18.79 ± 0.42b 1.31 ± 0.04c 2.65 ± 0.05d 13.50 ± 0.22c 31.63 ± 2.56a SSMT 21.40 ± 0.29a 2.16 ± 0.22a 5.28 ± 0.12a 14.80 ± 0.17b 25.47 ± 1.15b SM 15.36 ± 0.45c 0.71 ± 0.16d 3.09 ± 0.23c 15.03 ± 0.42a 36.65 ± 1.15a SMT 22.34 ± 0.59a 1.17 ± 0.05c 4.73 ± 0.04b 13.07 ± 0.68c 21.42 ± 1.06b Means in the same column with the same letter are not significantly different; P ≤ 0.05. FCMT = full cream milk with 40 % tiger nuts, SSMT = semi-skimmed milk with 40 % tiger nuts, SMT = skimmed milk with 40 % tiger nuts, FCM = full cream milk, SSM = semi-skimmed milk, SM = skimmed milk. 4.3 pH of ‘‘Burkina’’ Samples The pH of the “Burkina” samples was acidic (3.78 – 3.98) but was not affected by fat content or the addition of tiger nut milk (Table 4). The pH of food is very important in food applications, food preservation, food packaging and storage (Egbebi & Bademosi, 2011; Fekria et al., 2012). The pH of food products also influences sensory parameters such as taste, colour, texture, and flavour (Andrés-Bello et al., 2013). During food processing, pH affects many processes such as coagulation, enzymatic activities, mortality of microorganisms, and chemical reactions such as fermentation. Thus the knowledge of pH effects and its control during processing are important for product safety and quality (Andrés- Bello et al., 2013). 48 University of Ghana http://ugspace.ug.edu.gh Table 4 depicts the mean pH of “Burkina” samples: Table 4: Mean pH of ‘‘Burkina’’ Samples ‘‘Burkina’’ Sample pH FCM 3.85 ± 0.53 FCMT 3.98 ± 0.24 SSM 3.91 ± 0.12 SSMT 3.82 ± 0.09 SM 3.93 ± 0.05 SMT 3.78 ± 0.45 Values are means and standard deviations of triplicate analysis. FCMT = full cream milk with 40 % tiger nuts, SSMT = semi-skimmed milk with 40 % tiger nuts, SMT = skimmed milk with 40 % tiger nuts, FCM = full cream milk, SSM = semi-skimmed milk, SM = skimmed milk. Skimmed milk contains 0 % milk fat, semi- skimmed milk contains 2 % milk fat and full cream milk contains 4 % milk fat 4.4 Microbiological Wholesomeness of ‘‘Burkina’’ Samples ‘‘Burkina’’ samples were analysed to ascertain microbiological wholesomeness. This was to ensure that the samples could be consumed without adverse effects such as food poisoning or food infection due to the presence of harmful microorganisms in the ‘‘Burkina’’ samples. Table 5 shows the mean count of microorganisms in the ‘‘Burkina’’ samples. 49 University of Ghana http://ugspace.ug.edu.gh Microbiological counts were observed in the “Burkina” samples (Table 5). However, these counts were not significant to pose a health risk to consumers. The products were considered to be safe for consumption because the counts did not exceed the maximum permissible amount stated by the Ghana Standards Authority (GSA, 2010). There was a significant difference (p ≤ 0.05) between samples containing tiger nut milk and samples without tiger nut milk. Samples containing tiger nut milk were the only samples to have counts for yeast and molds. Since the tiger nut tubers, which are already rich in nutrients, were respiring when stored, the combination of heat, moisture and nutrient provided the congenial environment for yeast and mold growth. However, the counts did not exceed acceptable amounts considered to be safe for human consumption (GSA, 2010). Table 5: Microbiological Analyses of ‘‘Burkina’’ Samples (Mean Counts) Agar/Microorganism FCM SSM SM FCMT SSMT SMT PCA 3 3 3 3 3 3 9.8x10 8x10 8.7x10 9x10 9.4x10 8.8x10 Coliform 0 0 0 0 0 0 Staph. aureus 0 0 0 0 0 0 Salmonella 0 0 0 0 0 0 E. coli 0 0 0 0 0 0 Yeast & mold 0 0 0 3 3 3 1.0x10 1.1x10 1.0x10 50 University of Ghana http://ugspace.ug.edu.gh 4.5 Instrumental Colour Analysis of ‘‘Burkina’’ samples L value is measured from 0 – 100, with 0 representing black and 100 representing white on the scale. L values were significantly lower (p ≤ 0.05) for ‘‘Burkina’’ made with composite milk. The addition of Tiger nut milk resulted in a darker ‘‘Burkina’’ drink (Table 6). The ‘b’ values were all positive (Table 6), indicative of the fact that the ‘‘Burkina’’ samples had shades of yellow colouration. However, ‘a’ values were both positive and negative (Table 6), indicative of the fact that ‘‘Burkina’’ samples had shades of red and green (Minolta, 1991). There were higher ‘b’ values in the composite ‘‘Burkina’’ samples compared with their respective formulations without Tiger Nuts. This may be due to the transfer of some pigment colour from the outer layer of Tiger nuts. The Tiger nut variety used had yellowish colour which may have contributed to the higher ‘b’ values recorded (Minolta, 1991). The mean colour (L, a, b) and ∆E values for ‘‘Burkina’’ sample are shown in the table below: Table 6: Mean colour (L, a, b) and ∆E values for ‘‘Burkina’’ samples ‘‘Burkina’’ L A b ∆E Samples FCM 83.29 ± 0.23 a -3.01 ± 0.32a 13.53 ± 0.24a 18.50 FCMT 81.39 ± 0.14 b -2.28 ± 0.21b 14.97 ± 0.06b 40.71 SSM 86.58 ± 0.08c -2.87 ± 0.13b 12.80 ± 0.11c 15.55 SSMT 82.32 ± 0.07 d 2.84 ± 0.05c 14.55 ± 0.15b 19.99 SM 88.58 ± 0.15c 2.22 ± 0.16d 12.68 ± 0.28 e 14.09 SMT 81.39 ± 0.14d 2.28 ± 0.21d 14.43 ± 0.06b 20.56 Values are means and standard deviations of triplicates. Means in the same column with different superscripts are significantly different (p ≤ 0.05) FCMT = full cream milk with 40 % tiger nuts, SSMT = semi-skimmed milk with 40 % tiger nuts, SMT = skimmed milk with 40% tiger nuts, FCM = full cream milk, SSM = semi-skimmed milk, SM = skimmed milk 51 University of Ghana http://ugspace.ug.edu.gh 4.6 Consumer Focus Group Discussion and Sensory Evaluation of ‘‘Burkina’’ Samples Participants in the Focus Group Discussions (FGD) were between 18 and 50 years old with most of them between 18 – 24 years old. There were twice as many females as males in the FGD. The participants were students, workers or National Service personnel of the University of Ghana. The characteristics of the participants are elaborated in Table 7 below: Table 7: Characteristics of FGD Participants Characteristics No. of Participants N = 41 Sex Male 13 Female 28 Age 18-24 30 25-30 7 31-4 0 4 Occupation Student 29 Staff 6 Teac hing Assistant/National 6 Service Personnel 4.6.1 Consumer Focus Group Discussion The consumer focus group discussion centered on the panelists’ understanding of the desirabilty of “Burkina” and their perception on drinking “Burkina” with flavoured milk. The 52 University of Ghana http://ugspace.ug.edu.gh results for this discussion were coded into a global theme (Understanding the desirability of “Burkina”). The global theme was then broken down into sub-themes (Figure 6). Figure 6 demonstrates the key points associated with understanding the desirability of “Burkina”. Figure 6: Understanding the desirability of “Burkina” 4.6.1.1 Perceptions of Flavoured and Fermented Milk To determine whether consumers really understood what constituted ‘‘Burkina’’ milk beverage and their perception on flavoured ‘‘Burkina’’, the panelists were asked what they understood by the terms ‘fermented’ and ‘flavoured’ milk. It was observed that five out of six focus groups pointed out that fermented milk was milk that had either gone bad or expired. One of the focus groups mentioned that the milk is usually unrefrigerated, another focus group mentioned that there was bacterial action. Two of the focus groups raised sourness as an attribute of fermented milk. It was generally observed that some points raised in a 53 University of Ghana http://ugspace.ug.edu.gh particular focus group were also raised in a different focus group. Some focus groups also raised certain points which were unique to their group. A panelist from Focus Group 1 said: “I think that it is milk that has ‘expired’ and has lost its taste and has become sour; the original taste is no longer there” {Focus Group 1}. Another panelist in Focus Group 3 explained fermented milk as: “It is a sort of milk that bacteria action has worked on and it is milk that has stayed over its required period and due to respiration, it has changed its form, from one state to another affecting the taste and sometimes the appearance and texture of it” {Focus Group 3}. Based on themes (Figure 6) derived from these focus groups, it can be said that most of them knew what the term means since Benítez-Páez and Sanz (2017) and Roginski (2003) have mentioned sourness, bacterial action and similarity to milk going bad as some characteristics of fermented milk. Flavoured milk, on the other hand was described as ‘milk with additives added’ by one focus group and ‘milk with added flavour’ by five of the groups. Some panelists defined it as: “Anything being added is flavoured milk and it gives a particular scent” {Focus Group 4}. “Additives or preservatives added to it” {Focus Group 2}. Figure 7 indicates the responses given by the focus group panelists on their perception on flavoured and fermented milk. 54 University of Ghana http://ugspace.ug.edu.gh Figure 7: Perception of Flavoured and Fermented Milk Numbers in brackets represent the total number of focus groups with similar themes. Note that the themes with figures attached may appear in more than one focus group. 4.6.1.2 Perceptions of Whole and Skimmed Milk Majority of the focus groups (5) described skimmed milk as ‘milk with its fat extracted from it’ and one other group described it as ‘milk without cholesterol’. The focus group with a misconception about the term mentioned that it is ‘milk that has been pasteurized’. A panelist from focus group 3 in describing skimmed milk said: “I think it is milk with fat taken out of it, but I think it is boiled and after a while, when a layer is formed on top of the milk, the layer is removed because that layer is normally the fat” (Focus Group 3) A different panelist from focus group 1 also said: “It doesn’t have fat and doesn’t have too much cream” (Focus Group 1) 55 University of Ghana http://ugspace.ug.edu.gh Whole milk on the other hand was described as ‘raw unprocessed milk’ (3 FGD), ‘creamy milk’ (1 FGD) or ‘milk with its fats intact’ (4 FGD) (Figure 7). Some excerpts from the focus group discussions are as follows: “If skimmed milk means all the fats have been removed from it, then full milk has all the fats intact.” (Focus Group 2) “Full cream milk is the raw milk from the cow that has gone under no form of processing.” (Focus Group 6) Two of these definitions were right as Lu & Wang (2017) described skimmed milk as “milk which tends to contain around 0.1 % fat and is made when all the cream (also called milkfat) is removed from whole milk”. Lu & Wang (2017) also described whole milk as “milk with all the cream intact”. The definition of full cream milk from the panellist from Focus Group 6 could be classified as a misconception since Lu & Wang’s definition did not state that full cream milk is unprocessed milk. Figure 8 indicates the perceptions the panellists had on whole and skimmed milk: 56 University of Ghana http://ugspace.ug.edu.gh Figure 8: Perceptions of Skimmed and Whole Milk Numbers in brackets represent the total number of focus groups with similar themes. Note that the themes may appear in more than one focus group. 4.6.1.3 Perceptions of “Burkina” The following themes arose when the panelists were asked about their perceptions, source and packaging of ‘‘Burkina’’: “Burkina” composition, flavouring, colouring, texture, and source, as well as beliefs associated with the packaging, purchasing and consumption of “Burkina”. All six focus groups described ‘‘Burkina’’ as a milk beverage containing millet. Below are some statements made by the focus group panelists to buttress the above point: “I know it’s a local name for milk and millet. It is a milk and millet meal”. (Focus Group 3) “The millet is what makes it ‘Burkina’, milk without millet is not ‘Burkina’” (Focus Group 4) When asked about the type of flavoured ‘‘Burkina’’ the panelists would want to try, the following flavours came up: vanilla, banana, strawberry, chocolate, pineapple, tiger nut. 57 University of Ghana http://ugspace.ug.edu.gh Four of these groups mentioned that the milk used for ‘‘Burkina’’ production could be either fresh or in a powdered form: “I think its fresh milk but they sometimes add powdered milk” (Focus Group 2). Other attributes mentioned in the various focus groups included a white or creamish colour (run across all groups) and its thickness compared with porridge. Two of the focus groups however associated ‘‘Burkina’’ as a Northern food or food made by mostly northerners: “It’s a Northern food”. (Focus Group 5) The panelists also mentioned that they purchased their ‘‘Burkina’’ products from either University of Ghana campus (5 Focus groups), on the streets in traffic, at Madina or Kaneshie. The above descriptions about “Burkina” is however in line with the definition that Caiquo & Mensah (2013) gave which is: ‘‘Burkina’’ produces a mouth feel of a thick smooth (yoghurt- like) texture with small lumps and a grainy feel of millet’. Research conducted by Osei- Onumah (2014), also indicated that “Burkina” can be made with either fresh milk, milk powder or both. Caplice & FitzGerald (1999) also posited in their research that “Burkina” is a beverage that is indigenous to the three northern regions and is currently sold on the streets of Accra. Since Northerners are known to be the main producers of “Burkina”, it was not surprising that one of the panelists mentioned that it was a northern food and others also said it was sold at Madina and Kaneshie. 58 University of Ghana http://ugspace.ug.edu.gh When asked about panelists’ take on ‘Burkina’ made with skimmed milk, some groups felt it will be a healthier option. Other groups also mentioned that it might be tastier and lighter. The panelists associated skimmed milk with low fat content and believed that the reduction was a healthier option. Five of the focus groups mentioned that ‘‘Burkina’’ is usually packaged in a plastic bottle and sold on ice in ice chests or bigger plastic containers. Three groups however mentioned they would like to try ‘‘Burkina’’ packaged in a cup. One person from focus group five stated that: “If they have a small ice chest and it is covered. Plastic bottles are also fine.”(Focus Group 5) The thematic mapping on the panelists’ perceptions of “Burkina” is presented in Figure 9. Numbers in brackets represent the total number of focus groups with similar themes. Note that the themes with figures attached may appear in more than one focus group. Figure 9: Respondents’ Perceptions on “Burkina” 59 University of Ghana http://ugspace.ug.edu.gh 4.6.1.4 Facilitators to the Purchasing and Consumption of “Burkina” All focus groups indicated that there were certain facilitators that promoted the purchase and consumption of ‘‘Burkina’’. Proximity and affordability were major facilitators as they were mentioned by five of the focus groups (Figure 10). Below are some of the statements made by the panelists: “I don’t think I will walk all the way to night market for it but if it’s near me obviously I will by it.” (Focus Group 3) “if it is by my office and it is at an affordable cost, I will buy it every day, more than once a day.” (Focus Group 2 ) Two focus groups mentioned packaging as a facilitator, as it influences the aesthetics of the products and the desire to purchase it. Two focus groups also mentioned the quantity, quality and cost of the product as a facilitator. There was a group that mentioned allergies as one of the factors that will serve as deterrence to the consumption of ‘‘Burkina’’ but then the FGD stated that once the allergen is removed the desire to consume ‘‘Burkina’’ will be present: “I have allergies, so I can’t take so much, but if it is removed, I will double it.”(Focus Group 1) One group also mentioned that they will consider the tribe of the seller before purchasing the product. “I will buy ‘Burkina’ from the Northerner, if there are two people selling ‘Burkina’. I won’t buy from any other person aside Northerners”(Focus Group 2) 60 University of Ghana http://ugspace.ug.edu.gh Facilitators to purchasing and consumption of “Burkina” are summarized in Figure 10. Proximity and Affordability [5] Numbers in brackets represent the total number of focus groups with similar themes. Note that the themes may appear more than one focus group. Figure 10: Facilitators to the Purchasing and Consumption of “Burkina” 4.6.1.5 Barriers to the Purchasing and Consumption of “Burkina” Certain barriers deter people from consuming ‘‘Burkina’’. Some of these barriers were made known by the panelists during the focus group discussion (Figure 11). All focus groups mentioned the safety and hygienic state of the product as the major barrier since most people are sceptical when it comes to ‘‘Burkina’’ consumption. One Focus Group mentioned that they would not buy from the streets because they do not trust the source of the ‘‘Burkina’’: “I just cannot buy from people by the road side, I don’t trust their source of production” (Focus Group 3) 61 University of Ghana http://ugspace.ug.edu.gh The next major barrier is the temperature of the product. This barrier was observed in five of the focus groups. The panelists in those groups explained that they will prefer their product cold since it appealed to their taste and the product’s cold state will reduce the rate of microbial activity. The third major factor which was observed in four of the focus groups was the poor packaging of the product: “I think I wouldn’t buy if they are using a plain rubber. But if it comes in a good packaging I’ll buy it.” (Focus Group 3) Consumers have the behaviour of opting for products with attractive packaging. It is therefore expected that such a barrier would be brought up. Two of the focus groups mentioned that their dislike for millet and the smell of fresh milk will prevent them from buying and consuming ‘‘Burkina’’. It was observed in a single focus group that lactose intolerance or the presence of any allergen and inconsistencies in the taste of ‘‘Burkina’’ would deter them from ‘‘Burkina’’ consumption. These barriers have been summarized in Figure 11 below: 62 University of Ghana http://ugspace.ug.edu.gh Numbers in brackets represent the total number of focus groups with similar themes. Note that the themes may appear more than one focus group. Figure 11: Barriers to the Purchasing and Consumption of “Burkina” 4.6.1.6 Perceptions of “Burkina” with Tiger Nut The panelists in the focus groups were asked about their perception on consuming ‘‘Burkina’’ incorporated with tiger nut milk (Figure 12). Five groups mentioned they will love the product since they will be tasting the rich nutty taste the tiger nuts would add. Below are some statements made by two different 63 panelists from focus groups 5 and respectively: “Since there is tiger nut milk already, it is possible to have tiger nut ‘Burkina’ and the taste will be interesting.” (Focus Group 5) “This might be great because I have heard of tiger nut milk” (Focus Group 4) Two of the focus groups however mentioned that the original ‘‘Burkina’’ taste would be altered and were a bit sceptical about trying such a product. “it will alter the taste of the original ‘Burkina’.” (Focus Group 1) 63 University of Ghana http://ugspace.ug.edu.gh Numbers in brackets represent the total number of focus groups with similar themes. Note that the themes may appear more than one focus group. Figure 12: Perceptions of “Burkina” with Tiger Nut Milk 64 University of Ghana http://ugspace.ug.edu.gh 4.6.2 Sensory Evaluation of ‘‘Burkina’’ Samples Sensory scores given by panelists ranged from 6.15 - 8.83 an indication of different levels of liking. ‘‘Burkina’’ samples had significant differences in all sensory attributes but flavour. The mean liking scores for the homogenous and composite ‘‘Burkina’’ samples were significantly different with the exception of flavour. This could be attributed to the fact that most of the panelists liked the rich nutty flavour of the tiger nuts. Results in Table 8 also indicated that the means from the mouthfeel of ‘‘Burkina’’ made with composite milk were significantly different as these products had a decreasing level of thickness as the milk fat content decreased. Amongst the ‘‘Burkina’’ samples made with composite milk, the product containing the full cream milk was rated the highest (7.54) since the panelists preferred a thicker beverage (Table 8). The homogenous ‘‘Burkina’’ sample however had its mouthfeel rated as the best (8.85) since it was perceived to feel thicker, creamier and smoother on the tongue. The pH of a product is known to have an influence on the level of sourness and the aftertaste of a product (Andrés-Bello et al., 2013). Though the pH of the ‘‘Burkina’’ samples were not significantly different from each other, the panelists preferred the aftertaste/sourness of the samples without the tiger nut milk most. Though the homogenous “Burkina” samples had the highest rating from the panelists, incorporation of tiger nut milk into “Burkina” is recommended as it would provide consumers with additional minerals. Also, consumers can also enjoy the health benefits associated with consuming tiger nuts. Table 8 shows the mean liking scores of the sensory attributes and the mean overall acceptability scores for the six (6) ‘‘Burkina’’ samples. 65 University of Ghana http://ugspace.ug.edu.gh Table 8: Mean Sensory Scores of ‘Burkina’ Samples Attribute SM SMT SSM SSMT FCM FCMT Overall 8.05a 6.99c 8.23a 7.46b 8.26a 7.46b acceptability Colour 7.23b 5.14d 8.02a 5.53d 8.08a 6.15c Aroma 7.78b 6.28c 8.08a 6.30c 7.77b 6.77c Flavour 8.02a 8.23a 8.15a 8.21a 8.83a 8.15a Mouth feel 8.30a 6.09c 8.54a 6.28c 8.85a 7.54b Aftertaste/ 8.38a 6.30c 8.69a 6.84c 8.54a 7.15b sourness 9 = Like Extremely; 5 = Neither Like nor Dislike; 0 = Dislike Extremely (means in the same row with the same letter are not significantly different; P ≤ 0.05). FCMT = full cream milk with 40 % tiger nuts, SSMT = semi- skimmed milk with 40 % tiger nuts, SMT = skimmed milk with 40 % tiger nuts, FCM = full cream milk, SSM = semi-skimmed milk, SM = skimmed milk 66 University of Ghana http://ugspace.ug.edu.gh CHAPTER FIVE 5.0 SUMMARY, CONCLUSION AND RECOMMENDATIONS 5.1 Summary This research studied the incorporation of tiger nut milk into the production of ‘‘Burkina’’, as well as homogenous ‘‘Burkina’’ samples (‘‘Burkina’’ without tiger nut milk), at different levels of milk fat content. The study developed a process for incorporating tiger nut milk into the process for making ‘‘Burkina’’ and followed a one factor design in which the tiger nut milk (40 %) was incorporated into ‘‘Burkina’’. The ‘‘Burkina’’ made from homogenous and composite milk had three fat contents, full cream milk, semi-skimmed and skimmed milk. The tristimulus colour (L.a.b - values), pH, mineral and proximate compositions, microbiology and sensory characteristics of both homogenous and composite mixtures of ‘‘Burkina’’ were analysed. Moisture content increased with decreasing amount of fat content. Mineral content was higher in ‘‘Burkina’’ with incorporated tiger nut milk compared with ‘‘Burkina’’ from homogenous milk. “Burkina” pH, which was acidic, was not affected by fat content or the addition of tiger nut milk. The significantly lower Tristimulus L values and the relatively higher ‘b’ values for ‘‘Burkina’’ made with tiger nut milk (40 %) implied that the colour was affected by the addition of tiger nut milk (40 %) to the ‘‘Burkina’’. There were no counts for salmonella, coliforms, E. coli and Staphylococcus aureus but there were acceptable low counts for yeast and molds in ‘‘Burkina’’ containing tiger nut milk. Though all six ‘‘Burkina’’ samples were generally accepted by the panelists, the ‘‘Burkina’’ samples without tiger nut milk had the highest rating. 67 University of Ghana http://ugspace.ug.edu.gh 5.2 Conclusion Composite milk can be formulated using Tiger nut milk and cow’s milk. ‘‘Burkina’’ made with composite tiger nut milk and cow’s milk had improved physicochemical attributes. Results from the proximate and mineral analyses of “Burkina” containing tiger nut milk indicated an increase in the protein, carbohydrate, fat and other mineral composition with the exception of calcium content. The results from the consumer FGD indicated that “Burkina” is a fermented milk beverage which should contain agglomerated millet. Certain factors such as packaging, proximity to source of “Burkina”, food safety, income and colour of the beverage influence the rate of consumption of the beverage. Also, “Burkina” incorporated with tiger nut milk was perceived to be a healthy option as well as the ones made with skimmed milk. Consumers also loved the rich nutty taste of the “Burkina” with tiger nut milk. Incorporation of tiger nut milk into “Burkina” will increase the nutritional content of the product and provide consumers with the health benefits associated with tiger nuts. . 5.3 Recommendations 1. This research focused only on the physicochemical and sensory properties of “Burkina” made with tiger nut milk. The effect of short and long-term storage should therefore be conducted on ‘‘Burkina’’ samples to estimate the shelf life of the product in order to determine how storage affects the physicochemical and sensory attributes of ‘‘Burkina’’. 2. This research focused only on substituting cow’s milk with tiger nut milk. The Focus Groups suggested flavour options such as banana, strawberry, chocolate and pineapple for ‘‘Burkina’’. 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The nuts of Cyperus esculentus. International Journal of BioResource Technology, 8: 215-216. 124. United Kingdom Food Standards Agency (2017). Composite products questions and answers. Codex Alimentarius Standards STAN-206-1999. General Standard for the use of Dairy terms. Retrieved on November 12, 2017, from https://www.food.gov.uk/sites/default/files/media/document/compositeproductsqand a.pdf 125. Watt, J.M. & Breyer-Brandwijk, M. G. (1962). The Medicinal and Poisonous Plants of South Africa. 2nd Improved Impression (2000). Briza Publications, Pretoria. 126. Wong, V. (2013). "Soy Milk Fades as Americans Opt for Drinkable Almonds". BusinessWeek. Retrieved on 5th May, 2018, from http://www.businessweek.com/articles/2013-08-21/soy-milk-fades-as-americans-opt- for-drinkable-almonds#r=hpt-fs 127. Yadav, D. N; Thakur, N., & Sunooj, K.V. (2012). Effect of Partially De-Oiled Peanut Meal Flour (DPMF) on the Nutritional, Textural, Organoleptic and Physico- Chemical Properties of Breads. Food and Nutrition Sciences. 3:471-476. 78 University of Ghana http://ugspace.ug.edu.gh APPENDICES Appendix 1: RECRUITMENT QUESTIONNAIRE FOR FOCUS GROUP DISCUSSION ON ‘BURKINA’ PRODUCT Thank you for showing an interest in this project. Kindly read this information sheet carefully before deciding whether or not to participate. If you decide not participate, there will be no disadvantage to you of any kind and we thank you for considering our request. The aim of this project is to select, recruit and screen potential panelists to be a ‘selected participant’ of a Focus Group Discussion under the project topic ‘Physicochemical and Sensory Evaluation of ‘Burkina’ made with Composite Milk’. By participating in this focus group discussion, you will get the emotional benefit that comes with giving your candid opinion on developing a ‘Burkina’ product which will have nutritional and some health benefits to the general populace. This test will take place at the Product Development Laboratory of the Department of Family and Consumer Sciences Annex on Wednesday, 18th April and Thursday, 19th April, 2018 (3 sessions each day). The schedule for each session is as follows (Circle the most convenient time for you): DATE SESSION TIME Wednesday, 18th of April, 1st 8am-10am 2018 2nd 12pm-2pm 3rd 3pm-5pm Thursday, 19th of April, 2018 1st 8am-10am 2nd 12pm-2pm 3rd 3pm-5pm Please circle or tick the appropriate response to all questions asked and fill in the open ended questions. A. DEMOGRAPHIC INFORMATION 1. Age Group o 18-24 o 25-30 o 31-40 o 41-50 o 51-60 2. Gender o Male o Female 3. Occupation 79 University of Ghana http://ugspace.ug.edu.gh o Lecturer o Teaching and Research Assistant o Student (please indicate level)…………………….. o Other (please specify)……………………………. 4. Place of residence (please specify)………………………… B. SCREENING (Kindly circle answer where appropriate) 1. Which of these foods are you allergic to? (circle as many as apply) a. Milk b. Millet c. Sugar d. None 2. Are you lactose intolerant? a. Yes b. No c. Maybe Kindly end here if you did not select “None” and “No” for questions 1 and 2 respectively. 3. Which of the following products do you consume? (check all that apply) frequency Most Product preferred Daily Weekly Biweekly Monthly Once (check a Year only one) Fresh milk (pasteurised) Processed Milk (Secondary Processing) Fermented Milk Yoghurt Cheese Ice cream Other (please specify) …………………………. 4. What do you like about the product(s) you selected? ………………………………………………………………………………………… ………………………………………………………………………………………… 5. What do you like about your most preferred or liked dairy product? ………………………………………………………………………………………… 6. Have you heard of the name ‘Burkina’? a. Yes b. No c. Maybe 7. Have you consumed ‘Burkina’ before? a. Yes b. No c. Maybe 80 University of Ghana http://ugspace.ug.edu.gh If the answer to question 7 is no, please skip to section C. 8. Is ‘Burkina’ a product that you enjoy consuming? a. Yes b. No c. Maybe 9. How often do you consume ‘Burkina’? a. Daily b. Weekly c. Monthly d. Once a year e. Twice a year 10. How much ‘Burkina’ can you consume at a sitting? a. 330 ml b. 500ml. c. 1 litre d. other (please specify) …………… 11. How do you like your ‘Burkina’ in terms of level of sweetness? a. Very sweet b. Moderately sweet c. Less sweet d. No sweetness 12. How do you like your ‘Burkina’ in terms of sourness? a. Very sour b. Moderately sour c. Less sour d. No sourness SECTION C Please provide us with your names, telephone numbers and email addresses so that we can reach you to remind you when the test date is almost due. Name ……………………………………………………………………………………. Telephone number Email address …………………………… …………………………………………… THANK YOU FOR YOUR PARTICIPATION!!!! 81 University of Ghana http://ugspace.ug.edu.gh Appendix 2: CONSENT FORM Project Title: Physicochemical and Sensory Evaluation of ‘‘Burkina’’ made with Composite (Cow and Tiger Nut) Milk. Principal Investigator: Pearl Nyarko-Mensah Address: Department of Family and Consumer Sciences, College of Basic and Applied Sciences, University of Ghana, Legon, Accra. General Information about Research The sensory aspect of this study seeks to involve the use of human subjects to investigate the acceptability of the ‘Burkina’ product as the panelists express the views and perception. This will involve you participating in a moderated focus group discussion on ‘Burkina’ in a relaxed atmosphere. The responses obtained from you will help us to optimize the product. This discussion will last for at most 120 minutes but not less than 45 minutes. Prior to the evaluation, the researcher will give you a few instructions and also an opportunity to ask questions related to the test. You will be served with samples to taste so you can indicate your degree of likeness for them. Kindly read this form and ask any questions before agreeing to be part of the study. Possible Risks and Discomforts This study will take place in the Food Product Development Laboratory at the Department of Family and Consumer Sciences Annex. There are no possible risks from tasting ‘Burkina’ samples unless you are allergic to milk and/or are lactose intolerant. Possible Benefits By participating in this consumer test, you will get the emotional benefit that comes with giving your candid opinion on developing a ‘Burkina’ product which will have nutritional and some health benefits to the general populace. Confidentiality The data you provide to us will be kept confidential by the research team. You will never be personally identified in any work published as a result of your participation in any consumer test without your prior consent. We will protect your personal information and not hand this to any third party. Compensation At the end of the study, you will be given a token to show our appreciation for your time spent on the project. This may be fruit juice/ice cream with meat pie or biscuit. You should 82 University of Ghana http://ugspace.ug.edu.gh understand that there is no economic benefit to you for participating in a sensory study, only the emotional benefit of knowing that you have contributed significantly to the development and improvement in the quality of our underutilized crops. This benefit cannot be overlooked. Additional Cost There is no additional cost to you for participating in a sensory study organized by the Department of Family and Consumer Sciences. Voluntary Participation and Right to Leave the Research Although we will like that you stay for the duration of the test, you should know that your participation is purely voluntary hence you have every right to withdraw without penalties. This will not negatively affect your personal relationship with the investigator, the department or the university as a whole. Termination of Participation by the Researcher It is possible that for some tests you sign up to participate in, some exclusion criteria will exempt you from participating. You will be notified of such studies at the onset. If in the middle of a test the investigator realizes that you are not capable of completing a test the investigator may ask you to discontinue the test. This does not have any negative consequence on your relationship with the investigator, the department or the university. You should understand that such decisions are made purely on the basis of preserving the scientific quality of the data we collect from our volunteering participants and have no personal bias to you. Notification of Significant New Findings To preserve the scientific quality of the data we collect in sensory testing, we are unable to disclose too much information about the products we test at the onset of the project. However, if your interest in the product is raised through your participation in the project, we can provide additional information about the product to you at the end of the project. You will have to leave your details with the investigator to share such information about the product with you at the end of the study. Contacts for Additional Information on product For information and questions about this study please contact: Pearl Nyarko-Mensah Department of Family and Consumer Sciences, University of Ghana Email: pnyarko-mensah@st.ug.edu.gh Tel: 0206595106 83 University of Ghana http://ugspace.ug.edu.gh VOLUNTEER AGREEMENT The above document describing the benefits, risks and procedures for the sensory evaluation of foods has been read and explained to me. I have been given an opportunity to have any questions about the research answered to my satisfaction. I agree to participate as a volunteer. _______________________ ______________________________________________ Date Name and signature of volunteer If volunteers cannot read the form themselves, a witness must sign here: I was present while the benefits, risks and procedures were read to the volunteer. All questions were answered and the volunteer has agreed to take part in the research. _______________________ _________________________________________________ Date Name and signature of witness I certify that the nature and purpose, the potential benefits, and possible risks associated with participating in this research have been explained to the above individual. _______________________ __________________________________________________ Date Name & Signature of Person Who Obtained Consent 84 University of Ghana http://ugspace.ug.edu.gh Appendix 3: Analysis of Variance Results for Sensory Attributes Appearance / color P- values 40% TN added to SSM vs SSM only 0.000 40% TN added to FCM vs FCM only 0.000 40% TN added to SM vs SM only 0.000 Taste 40% TN added to SSM vs SSM only 0.000 40% TN added to FCM vs FCM only 0.162 40% TN added to SM vs SM only 0.000 Mouthfeel 40% TN added to SSM vs SSM only 0.000 40% TN added to FCM vs FCM only 0.389 40% TN added to SM vs SM only 0.000 Aroma 40% TN added to SSM vs SSM only 0.000 40% TN added to FCM vs FCM only 0.510 40% TN added to SM vs SM only 0.000 Flavor 40% TN added to SSM vs SSM only 0.000 40% TN added to FCM vs FCM only 0.073 40% TN added to SM vs SM only 0.000  TN means tiger nut  SSM means semi skimmed milk  FCM means full cream milk  SM means skimmed milk  P- value was compared to level of significant or alpha 0.05. 85 University of Ghana http://ugspace.ug.edu.gh APPENDIX 4: ‘‘Burkina’’ Themes and Codes for FGD Code-Filter: All ______________________________________________________________________ HU: ‘Burkina’ File: [C:\Users\Grace\Desktop\Ernest docs\People\Pearl Malaika\MPhil analysis\’Burkina’.hpr7] Edited by: Super Date/Time: 2018-05-08 08:15:10 ______________________________________________________________________ Barriers to purchase - allergies/lactose intolerence Barriers to purchase - dislike for millet Barriers to purchase - dislike of scent of fresh milk Barriers to purchase - packaging Barriers to purchase - poor taste Barriers to purchase - quantity vrs cost Barriers to purchase - safety and hygienic perceptions Barriers to purchase - temperature ‘Burkina’ - milk and millet ‘Burkina’ color - white ‘Burkina’ color - white and creamy ‘Burkina’ flavor - banana, chocolate, strawberry ‘Burkina’ flavor - chocolate ‘Burkina’ flavor - fanice ‘Burkina’ flavor - no flavor ‘Burkina’ flavor - strawberry. ‘Burkina’ flavor - vanilla ‘Burkina’ flavor - vanilla, banana, strawberry, chocolate pineapple. ‘Burkina’ ingredients - Milk, millet, sugar ‘Burkina’ ingredients - sorghum ‘Burkina’ make_ fresh milk ‘Burkina’ make_ fresh milk and powdered milk ‘Burkina’ make_ powdered and processed milk ‘Burkina’ make_ thickness ‘Burkina’ taste_ sour Consume ‘Burkina’_ desire for it Difference - powdered milk expensive Difference_ depends on amount of milk added Difference_ no difference Difference_ powdered tastes nicer Difference_color powdered milk yellow, Difference_fresh milk taste nicer Fermented milk - bacteria action on milk Fermented milk - gone bad/expired Fermented milk - milk unrefrigerated Fermented milk - taste sour Flavored ‘Burkina’_ depends on flavor Flavored ‘Burkina’_ fruity Flavored ‘Burkina’_ like for it Flavored ‘Burkina’_ promotes variety Flavored milk - additives added Flavored milk - something added Flavoured milk - flavour added Handle - Keep in freezer Milk flavors - Apple, mango, chocolate, strawberry packaging - bottle Packaging - cup with spoon Packaging - ice chest 86 University of Ghana http://ugspace.ug.edu.gh Packaging - tetrapack perceived texture of ‘Burkina’ - btwn countre milk and koko perceived texture of ‘Burkina’ - countre milk perceived texture of ‘Burkina’ - koko perceived texture of ‘Burkina’ - koko and tom brown Perception of ‘Burkina’ - milk drink Perception of ‘Burkina’ - Northern food Perception of ‘Burkina’ with Skimmed milk - fat removed Perception of ‘Burkina’ with Skimmed milk - healthier Perception of ‘Burkina’ with Skimmed milk - light texture Perception of ‘Burkina’ with Skimmed milk - tastier Perception to purchase - high cost Perception to purchase - packaging Perception to purchase - proximity, affordability and desire Perception to purchase - quality Perception to purchase - remove allergic attributes Perception to purchase - tribe of vendor Perception_ ‘Burkina’ with tiger nuts - likeness Perception_ ‘Burkina’ with tiger nuts - taste altered. Perception_ ‘Burkina’ with tiger nuts - tiger nut milk Preference for 509 Preference for 509 and 019 Safety - Not safe Skimmed milk - fats extracted Skimmed milk - no idea Skimmed milk - pasteurized milk Skimmed milk - without cholesterol Source of ‘Burkina’_ both stationary and mobile vendors on the street Source of ‘Burkina’_ Campus Source of ‘Burkina’_ campus and market Source of ‘Burkina’_ markets Source of ‘Burkina’_ Muslim community Source of ‘Burkina’_ On the street Storage - a week Storage - drink it immediately Storage - less than a week Whole milk - fats intact Whole milk - unprocessed raw milk Whole milk - very creamy 87 University of Ghana http://ugspace.ug.edu.gh Appendix 5: Discussion Guide for Focus Group Discussion Introduction My name is Pearl Nyarko-Mensah and I will be your moderator for today. The purpose of this discussion is to talk about Burkina and to understand your opinion on the desirable attributes of Burkina and what you would consider as a good packaging for the safety of the product. Information about characteristics and unique attributes of this product are needed to improve the product and to complete the research. Your views and concerns will provide this information which is guaranteed absolute confidentiality. However, the discussion will be recorded to make sure every information is captured. RULES 1. This discussion will last between 75 to 90 minutes depending on your cooperation and the kind of information we get. 2. There are no right or wrong answers. Every answer is correct. 3. As much as possible let us respect each other’s views and comments because these views are helpful in the modification of our product. 4. Please avoid interrupting each other when talking to ensure clarity. 5. All phones should be put on silence so as to prevent interference with the recorder. 6. Please be audible and speak with confidence. 7. Any questions before we begin the discussion? We will like to start by getting to know your names. QUESTIONS Perception on Milk and Burkina 1. What do you know about skimmed milk and whole milk? 2. What do you understand by the term fermented milk? 3. What do you understand by the term flavoured milk? Probe: Kindly give some examples and the type of flavours. Fanyogo, Vita milk, Country milk, etc. 4. In your opinion, what is Burkina? What do you know about the ingredients used in making Burkina? Probe for what type of milk: fresh milk or powdered milk or both milk. 5. Are there any differences between the fresh milk and powdered milk Burkina? Probe: taste, colour, texture, etc 6. What are the key quality attributes that make a Burkina product? Probe: millet added, texture, sourness, tingling effect, colour, etc. 7. Where do you normally get Burkina from? Where do you get the Burkina you consume from? 8. What is your take on having Burkina made with skimmed milk? 88 University of Ghana http://ugspace.ug.edu.gh 9. Are there any barriers to the purchase and consumption of Burkina? What are some of the barriers to the purchase and consumption of Burkina? Probe: safety, proximity, cost, temperature, religious beliefs, allergies etc 10. If the barriers are removed, will it affect your purchase and consumption of Burkina and by how much? Why? 11. How will you feel about having flavoured Burkina? 12. What kinds of flavoured Burkina will you like to consume? Probe: banana, tiger nuts, strawberry, guava, etc. Probe for tiger nuts if it is not mentioned. 13. Do you consume tiger nuts? In what form do you consume the tiger nuts? Mention the forms 14. What is your opinion about tiger nut flavoured Burkina? Packaging and Safety 1. How do you handle the Burkina you purchase? For how long do you store the Burkina you purchase? 2. What is your take the Burkina samples sold on the streets? Would you say they are safe for consumption? Why? 3. What will you say will be an ideal packaging for Burkina with regards to food safety? 89