EFFECT OF DIFFERENT MARINADES ON QUALITY 
CHARACTERISTICS OF CHEVON JERKY 
 
 
BY 
 
GIFTY MOORE ARTHUR 
(10507201) 
 
 
 
 
THIS THESIS IS SUBMITTED TO THE UNIVERSITY OF GHANA, LEGON 
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD 
OF MASTER OF PHILOSOPHY DEGREE IN ANIMAL SCIENCE 
 
 
 
 
 
 
 
JULY, 2017
DECLARATION 
I hereby declare that this thesis which is submitted to the Department of Animal 
Science, College of Basic Applied Sciences, University of Ghana, for the award of 
Master of Philosophy in Animal Science degree is the result of my own investigation. 
This thesis has not been submitted or presented for another degree elsewhere, either in 
part or in whole, except for other people‘s work which was duly cited and 
acknowledged. 
 
 
 
STUDENT 
NAME: GIFTY MOORE ARTHUR 
SIGNATURE:……………………………… 
DATE:……………………………………… 
 
 
SUPERVISOR                                                           CO - SUPERVISOR 
NAME: DR. S. OHENE – ADJEI                           PROF ANNA. R. BARNES 
SIGNATURE:…………………………  ……………………………… 
DATE:……………………………………   ……………………………… 
 
i 
 
DEDICATION 
This work is dedicated to my son Jethro Nana Eduah Ansah,my husband Raymond 
Ansah, my parents Mr. George Edward Moore Arthur and Madam Bernice Eshun, my 
siblings James Moore Arthur, Mrs. Constance Irene Cofie and Mrs. Patience Bernette 
and lastly to my niece Princess Lisa Cofie. 
 
 
  
ii 
 
ACKNOWLEDGEMENTS 
I am very grateful to the Almighty God, the creator and designer for the wisdom and 
knowledge he has bestowed on me. Dr. S. Ohene - Adjei my supervisor also deserves 
special commendation for his priceless dedication and support geared towards this 
dissertation. I also wish to thank Prof. A. R. Barnes my co- supervisor, for the advice 
and proof reading. My profound gratitude goes to Dr. Patrick Arthur of the 
Department of Biochemistry for his support and advice. I will also wish to thank Dr. 
Raphael A. Ayizanga for his support, advice and encouragement. I will also like to 
acknowledge the entire staff of the Faculty of Agriculture, College of Basic and 
Applied Science, especially those in the Animal Science Department for their support, 
encouragement and guidance. 
 
Finally, I will like to acknowledge Akua Kumi Yeboah, Mrs. Sarah Afia Addo, 
Madam Rebecca Otoo and Madam Esther Akomaning, Alex Addo, Gifty Ziema 
Bumbie, my fellow graduate students and my sensory panelists for the diverse ways in 
which they contributed to the success of this dissertation. It is my prayer that all your 
heart desires will be accomplished by God and he will crown all your effort with 
success. 
 
  
iii 
 
TABLE OF CONTENTS 
Declaration ................................................................................................................. i 
Acknowledgements .................................................................................................. iii 
Table of contents ...................................................................................................... iv 
List of tables ............................................................................................................. ix 
List of figures ............................................................................................................ x 
Abstract .................................................................................................................... xi 
CHAPTER ONE........................................................................................................ 1 
1.0 Introduction ................................................................................................. 1 
1.1 Problem Statement ...................................................................................... 4 
1.2 Objectives ................................................................................................... 5 
1.3 Justification ................................................................................................. 5 
1.4 Hypothesis .................................................................................................. 6 
CHAPTER TWO ....................................................................................................... 7 
2.0 Literature Review ........................................................................................ 7 
2.1 History of Jerky ........................................................................................... 7 
2.2 Manufacturing Process ................................................................................ 8 
2.3 Marinade ..................................................................................................... 9 
2.3.1 Functionality of Marinades ................................................................. 10 
2.4 Acidic Marinades ...................................................................................... 11 
2.4.1 Tenderisation Action of Acidic Marinades in Meat ............................. 11 
2.4.2 Antimicrobial Effect of Acidic Marinades .......................................... 13 
iv 
 
2.5 Enzymatic Marinades (Exogenous Proteolytic Enzymes) ........................... 15 
2.6 Papain .................................................................................................... 18 
2.6.1 Myofibrillar and Connective Tissue Degradation by Papain................ 19 
2.7 Marinating Techniques and Duration ......................................................... 20 
2.7.1 Marinating Methods ........................................................................... 20 
2.7.2 Immersion .......................................................................................... 20 
2.7.3 Multi-needle Injection Marinating ...................................................... 21 
2.7.4 Vacuum or Manual Tumbling ............................................................. 22 
2.8 Marinade Ingredient Functionality ............................................................. 23 
2.8.1 Spices ................................................................................................. 23 
2.8.2 Salt (sodium chloride) ........................................................................ 24 
2.8.3 Soy Sauce ........................................................................................... 25 
2.8.4. Sweeteners ......................................................................................... 26 
2.9 Preservation of Meat.................................................................................. 27 
2.9.1 Odka .................................................................................................. 29 
2.9.2 Qwanta ............................................................................................... 29 
2.9.3 Biltong ............................................................................................... 29 
2.9.4 Kilishi ................................................................................................ 30 
2.10 Drying of Meat .......................................................................................... 30 
2.10.1 Methods of Drying Meat .................................................................... 31 
2.10.2 Natural or Traditional Drying Method ................................................ 32 
v 
 
2.10.3 Sun Drying ......................................................................................... 32 
2.10.4 Solar Drying ....................................................................................... 32 
2.11 Artificial Heat Source ................................................................................ 33 
2.11.1  Smoke House Drying ...................................................................... 33 
2.11.2  Oven Drying ................................................................................... 34 
2.11.3  Freeze Drying ................................................................................. 34 
2.12 Rehydration Rate ....................................................................................... 36 
2.13 Microbiology of Meat and Meat Products .................................................. 36 
2.14 Food Safety Concerns of Jerky .................................................................. 37 
2.15 Principles of Preservation of Shelf-Stable Dried Meat Products ................. 39 
2.16 Shelf-Stability and Hurdle Effect ............................................................... 40 
2.17 Packaging .................................................................................................. 42 
2.18 Eating Qualities of Meat ............................................................................ 44 
CHAPTER THREE ................................................................................................. 50 
3.0 Materials and Methods .............................................................................. 50 
3.1 Experimental Design ................................................................................. 50 
3.2 Sample Preparation .................................................................................... 50 
3.2.1 Treatments ......................................................................................... 51 
3.2.2. Marination .......................................................................................... 51 
3.2.3 Drying ................................................................................................ 51 
3.3 Measurement ............................................................................................. 52 
vi 
 
3.3.1 pH Measurement ................................................................................ 52 
3.3.2 Sensory Evaluation ............................................................................. 52 
3.3.3. Rehydration Ratio .............................................................................. 53 
3.3.4 Microbiological Analysis .................................................................... 54 
3.4 Statistical Analysis .................................................................................... 55 
CHAPTER FOUR ................................................................................................... 56 
4.0. Results ...................................................................................................... 56 
4.1 Sensory Evaluation .................................................................................... 56 
4.1.1 Effect of Treatments on Chevon Jerky Tenderness ............................. 56 
4.1.2 Effect of Treatments on Chevon Jerky Chewiness .............................. 59 
4.1.3 Effect of Treatments on Chevon Jerky Juiciness ................................. 61 
4.1.4 Effect of Treatments on Chevon Jerky Flavour ................................... 63 
4.1.5 Effect of Treatment on Chevon Jerky Acceptability ............................ 65 
4.2 Microbiological Evaluation ....................................................................... 67 
4.2.1 Effect of Treatment on Total Plate Count............................................ 68 
4.2.2 Effect of Treatment on E.coli .............................................................. 69 
4.2.3 Effect of Treatment on Staphylococcus aureus ................................... 69 
4.2.4 Effect of Treatment on Yeast and mould ............................................. 70 
4.3 Moisture content (%) ................................................................................. 71 
4.4 Rehydration Characteristics ....................................................................... 73 
 
vii 
 
CHAPTER FIVE ..................................................................................................... 75 
5.0 Discussion ................................................................................................. 75 
5.1 Sensory Evaluations .................................................................................. 75 
5.2 Microbiological Evaluation ....................................................................... 79 
5.3 Moisture Content (%) (Drying curve) ........................................................ 82 
5.4 Rehydration Rate ....................................................................................... 85 
CHAPTER SIX ....................................................................................................... 87 
6.0 Summary, Conclusions and Recommendations .......................................... 87 
6.1 Summary ................................................................................................... 87 
6.2 Conclusions ............................................................................................... 90 
6.3 Recommendations ..................................................................................... 90 
References ............................................................................................................... 91 
 
 
 
 
 
 
 
 
 
  
viii 
 
LIST OF TABLES 
Table 1: Enzymes Classified as ―Generally Recognised As Safe‖ (GRAS) for Meat 
Tenderisation ........................................................................................................... 18 
Table 2: Treatments of chevon jerky with papain and vinegar at various concentration 
levels ....................................................................................................................... 51 
Table 3: Frequency (%) of panelist‘s response on tenderness scale of chevon jerky . 57 
Table 4: Frequency (%) of panelist‘s response on the effect of storage period on 
tenderness of chevon jerky ....................................................................................... 58 
Table 5: Frequency (%) of panelist‘s response on chewiness scale of chevon jerky .. 59 
Table 6: Frequency (%) of panelist‘s response on the effect of storage period on 
chewiness of chevon jerky ....................................................................................... 60 
Table 7: Frequency (%) of panelist‘s response on juiciness scale of chevon jerky .... 61 
Table 8: Frequency (%) of panelist‘s response on the effect of storage period on 
juiciness of chevon jerky ......................................................................................... 62 
Table 9: Frequency (%) of panelist‘s response on flavour scale of chevon jerky ...... 63 
Table 10: Frequency (%) of panelist‘s response on the effect of storage period on 
flavour of chevon jerky ............................................................................................ 64 
Table 11: Frequency (%) of panelist‘s response on acceptability scale of chevon jerky
 ................................................................................................................................ 65 
Table 12: Frequency (%) of panelist‘s response on the effect of storage period on 
acceptability of chevon jerky ................................................................................... 66 
Table 13: Effect of treatments on microbial count (log CFU/g meat sample) of 
vacuum packaged chevon jerky stored for 30d ......................................................... 67 
Table 14: Effect of storage time on microbial count (log CFU/g meat sample) of 
vacuum packaged chevon jerky stored for 30d ......................................................... 68 
ix 
 
LIST OF FIGURES 
Figure 1: The effect of papain and vinegar on moisture content of chevon jerky during 
drying ...................................................................................................................... 71 
Figure 2: Effect of treatments on rehydration on percent moisture content (%MC) of 
chevon jerky ............................................................................................................ 73 
 
 
 
  
x 
 
ABSTRACT 
This study was carried out to investigate the effect of different marinades on quality 
characteristics of chevon jerky. Chevon (Hindquarter muscle) was treated with 
marinades containing different levels of vinegar (0, 2.5% or 5% v/v) and papain (0, 
0.004g/0.04gw/v). A 3x3 factorial design which composed of nine treatments with 
three replicates was used. Chevon was cut into 1.5cm x 1.5cm cubes and samples 
o
were marinated for 12h and dried in an oven for 10h at temperature of 65 C. Sensory 
and microbial characteristics, drying rate and rehydration ratio were determined. The 
samples for sensory analysis were vacuum packaged after drying and stored at room 
temperature. Due to the risk of mould growth on samples from treatments containing 
papain only (T2 and T3) after 15d of storage in a preliminary work, sensory 
evaluation was conducted on samples stored for 1d and 15d. Panelists were presented 
with randomly coded cooked samples and the tenderness, chewiness, juiciness; 
flavour and overall liking of the samples were evaluated using 8 point hedonic scale. 
The result of sensory properties showed that out of the nine treatments tested, papain 
(0.04g) was effective in tenderising the chevon jerky compared with all the other 
treatments. Samples were ranked as very tender to extremely tender while samples 
treated with vinegar (5%) was ranked as moderately tough to slightly tough.  Samples 
from control (T1) obtained the highest acceptability score of 52.78% and was ranked 
as ―very like to extremely like‖ whereas papain 0.004g +vinegar 2.5% (T5) was the 
least scored 38.88% and was ranked as ―slightly like to moderately like‖. No 
significant (p > 0.05) differences were observed among treatments for chewiness, 
juiciness and flavour. However, juiciness improved with longer storage time at 15d. 
Samples evaluated at 1d were rated as ―extremely dry to very dry‖ (24.69%) but were 
ranked as ―very juicy to extremely juicy‖ (24.08%) at 15d. Samples for microbial test 
xi 
 
were also vacuum packaged and stored at room temperature. Additionally, microbial 
quality analysis was conducted at 1d, 15d and 30d of storage and the effects of the 
nine treatments on the growth of four different microbes (total plate count, 
Staphylococcus aureus, E.coli, yeast and mould) during storage were investigated. As 
storage period increased from 15 to 30d total plate count increased from1.59 to 
1.93log cfu/g, while E.coli count declined from 0.19 to 0.09log cfu/g. Additionally, 
Staphylococcus count decreased from 1.96 to 0.00log cfu/g and lastly as storage 
period progressed from 15d to 30d yeast and mould count declined from 1.17 to 
0.30log cfu/g. Drying rate was determined by change in % moisture content per unit 
time during drying for 10h. The analysis showed that all the test samples recorded 
lower moisture content compared to that of the control (T1) after drying. Samples 
from vinegar (2.5%) recorded the least (1.71%) moisture content whereas the highest 
(3.61%) was observed in control (T1) samples. Rehydration studies were carried out 
on sample (1.5cm x 1.5cm) to distilled water ratio of 1:40 for 300min under ambient 
condition. As rehydration time progressed from time 0 to 300min there was an 
increase in weight among all test samples. Samples from control (T1) recorded the 
least moisture uptake of 9.83 whereas samples from vinegar 2.5% (T4) recorded the 
highest moisture uptake (19.94) after rehydration. Overall, the results of this study 
indicate that although overall likeness score favoured the control treatment, it is 
possible to improve meat toughness using papain to produce meat with acceptable 
sensory attribute than vinegar. Also, the drying process resulted in a jerky product 
with low moisture content which inhibited microbial growth; however, vinegar can be 
used in jerky production to add flavour to the product. 
xii 
 
CHAPTER ONE 
1.0 Introduction 
Meat is an excellent source of many important nutrients; however, it is subject to high 
rate of deterioration. It is also an ideal environment for bacterial to thrive due to its 
high protein and moisture contents (Bhaisare et al., 2014). Microbial deterioration of 
meat begins soon after exsanguinations. The quantity of spoilage microorganism 
present in fresh meat at the time of processing has an impact on product‘s shelf life. 
Bacteria, mould and yeast are the three common microorganisms found in meat. The 
moulds and yeast growing on meat are aerobic whereas bacteria thriving in meat 
could be aerobic, anaerobic or facultative (Jay et la., 2008). Some additional 
organisms of concern affiliated with meat in general are Salmonella, Escherichia coli, 
Staphylococcus aureus etc (Romans et al., 1994).Therefore, meat processing methods 
such as refrigeration, canning and drying aim at limiting microbial growth at the least, 
making it possible to extend shelf life and also introduces variety of meat products. 
The process of freezing may decrease the number of microorganisms during storage. 
However, some species of bacteria found during refrigerated storage such as 
Pseudomonas, Brochothrix thermosphacta and lactic acid bacteria (LAB) 
(Lactobacillus, Carnobacterium, and Leuconosto) etc can survive this process and 
resume growth (Labadie, 1999; Ellis and Goodacre, 2001; Pin, et al., 2002). On the 
other hand most traditional products have relied on salting and drying as a means of 
meat preservation.  
 
Jerky is a form of processed meat in which fresh meat is dried to prevent it from early 
deterioration. The meat may be cut into smaller pieces or minced and then mould into 
strips or put into narrow casings (Nummer et al., 2004). Salt, spices or marinades are 
1 
 
used to inhibit microbial growth and to flavour the meat (USDA - FSIS, 2004).  Jerky 
can be processed from basically any defatted meat such as beef, chicken, pork 
(Calicioglu et al., 2003; Pegg et al., 2006; Han et al., 2007) and chevon. 
 
Quality characteristics of meat products deteriorate due to microbial growth and 
rancidity of lipids in the course of storage (Aguirrezabal et al., 2000). The intent of 
processing and preservation is to mitigate such processes to extend the shelf life of 
processed meat products. To attain stability, jerky is dehydrated to water activity 0.70 
to 0.85 (Quintion et al., 1997), without the need for refrigeration due to the control of 
the growth of bacteria at low water activity. However, despite the imposition of this 
hurdle (low water activity) in jerky manufacturing, the connection of jerky products 
with food borne disease outbreaks (CDC, 1995; Eidson et al., 2000) has raised 
questions about their safety. In order to address this challenge, vinegar can be used to 
effectively control pathogens in jerky products (Calicioglu et al., 2002a). Acetic acid 
(vinegar) is usually used in the meat manufacturing sectors as an organic chemical to 
decontaminate meat (Ricke, 2003). Acetic acid exerts its action based primarily on its 
acidifying influence. It manifests this acidifying action only in an undissociated form 
(Sofos et al., 1998). Acetic acid efficacy in arresting development or destroying food 
pathogenic bacteria could differ among treatments based on the percentage of 
undissociated acid at a given pH. Generally, all products treated with organic acids 
could restrict microbes‘ development or existence; however the degree of their 
existence is based on the types of organism harboured in the meat and the kind and 
quantity of organic acid, especially its buffering capacity. 
 
2 
 
Whole muscle jerky is tough due to the low moisture content to prevent microbial 
growth. Some restructured jerky products have a tender texture yet high in fat and 
water activity, which induced lipid rancidity and microbial growth (Quinton et al., 
1997). On the other hand, whole muscle jerky can also be reconstituted in water to 
soften it; however, it is time consuming. According to Huffman et al. (1996) a very 
tender meat is considered as the most essential eating property by consumers. 
Researchers have shown that meat tenderness is chiefly linked with the structural 
firmness of myofibrillar and connective tissue proteins (Marsh and Leet, 1966; 
Nishimura et al., 1995). Several methods, including mechanical tenderisation, 
elevated-temperature storage, calcium chloride injection, electrical stimulation, 
organic acids treatments and enzymatic tenderisation, have also been used to enhance 
meat tenderness (Moeller et al., 1976; Savell et al., 1981; Koohmaraie et al., 1988; 
Koohmaraie, 1992; Hwang et al., 2000). Jerky toughness can be altered by the 
application of enzymatic tenderisers such as papain and bromelain. Papain is an 
enzymatic protease with very broad specificities and degrades connective tissue and 
myofibrillar proteins, sometimes leading to excessive tenderisation and distortion of 
sensory attribute (texture) of product (Miller et al., 1989). Chen et al. (2006) reported 
that papain tenderise meat within a short time and is superior because of safety issues 
such as pathogenicity, compared to the other procedures of meat tenderisation. 
Similarly, bromelain is an enzymatic protease that exists naturally in pineapple plant 
and has been applied broadly as a meat tenderiser (Omojasola et al., 2008). However, 
Sullivan and Calkins (2010); Rawdkuen and Benjakul (2012) reported that papain is 
most effective in improving meat tenderness than bromelain. The two most often used 
enzymes in marinades are papain and bromelain. 
3 
 
A marinade is a sauce which is designed to flavour and tenderise meats. Additionally, 
they improve meat juiciness and also enhance protection and shelf life of processed 
meat products through inhibition of microbial development (Alvarado and McKee, 
2007). The efficacy of most marinades is based on the ingredients that are used 
(organic acids, soy sauce, essential oils, salts, tenderisers and spices). Therefore, there 
is the need to explore the benefits of marinades to enhance meat quality. The 
Government of Ghana‘s policy is to increase small ruminant production and has 
supported 90 farmers in the Central, Western and Eastern regions with superior breeds 
of 650 sheep and 450 goats under the West Africa Agricultural Productivity 
Programme (WAAPP) (Ablordeppey and Osabutey, 2015). There is the possibility of 
a potential increase in chevon production and value addition will be required to 
improve marketability of the raw meat, therefore the need to introduce jerky as a form 
of meat preservation. 
 
1.1 Problem Statement 
Most animals slaughtered in Ghana for meat consumption are over aged and meat 
tenderness decreases as animals increase in age. The decreased tenderness is due to 
increase in collagen cross-linking which is regarded as the chief determinants of meat 
texture. Meat from over aged animals require longer cooking time for it to tenderise, 
chewing such meat is also difficult and it will as well require a longer digesting time. 
Since jerky is dried to a low water activity in order to inhibit microbial growth, one 
might anticipate that using whole muscle from over aged animals would result in very 
tough and coarse textured jerky. Additionally, despite the low water activity there 
have been several reports on the outbreak of food borne diseases connected with the 
consumption of snack meat products (CDC, 1995; Eidson et al., 2000). Hence, this 
4 
 
has raised questions about their safety, since jerky is consumed without further 
cooking. There is a dearth of knowledge in the use and effect of acidic and enzymatic 
marinades in the meat processing industry. 
 
1.2 Objectives 
The general objective of this study is: 
To evaluate the effect of acidic (vinegar) and enzymatic (papain) marinades on quality 
characteristics of chevon jerky (produced by oven drying). 
 
The specific objectives are: 
1. Evaluate the effect of the marinades on sensory characteristic of chevon jerky.  
2.  Compare the effect of the treatments on microbial characteristics and shelf life 
of chevon jerky during storage. 
 
1.3 Justification 
There is an ongoing programme by the Government of Ghana supporting farmers with 
improved breeds of sheep and goat, which is aimed at increasing small ruminant 
production in the country. With the possibility of a potential increase in chevon 
production, value addition will be required to improve marketability of the raw meat. 
Jerky manufacturing is simple and cheap way to dry fresh meat to prevent it from 
deteriorating. With regard to introduction of pathogens into meat through the use of 
non-meat ingredients, papain is superior compared to other bacterial derived enzymes 
used as meat tenderisers. Additionally, papain tenderise meat within a short time and 
is most often more effective compared to other enzymatic tenderisers such as 
bromelain, ficin and B. subtilis proteases. On the other hand, vinegar is an organic 
5 
 
acid which effectively control pathogens in meat products. Marinades enhance quality 
of meat products, therefore, there is the need to explore the benefits of marinades to 
produce jerky products with desired sensory quality and microbiologically safe. 
 
1.4 Hypothesis 
1. Addition of acidic and enzymatic marinades will improve microbial 
characteristics, sensory attributes and shelf life of chevon jerky. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6 
 
CHAPTER TWO 
2.0 Literature Review 
2.1 History of Jerky 
Around the year 1550s jerky was identified with the indigenous tribe (Quechua) from 
the Southern part of America and also previously from the Inca empire. They called 
meat that has been burnt ‗charki‘. The Quechua used meat from the alpaca and llamas 
with the fat and bone removed, the meat was then cut into strips and pounded thin and 
tumbled with salt. The meat was then sun dried or smoked over a fire. The Spanish 
Conquistadors developed the process and finally called it Charqui. After the Spanish 
captured the Northern part of America they noticed that the indigenous were drying 
meat from buffalo, elk and deer, within some short period the local people acquired 
the Spanish word, Charqui, only adding their tone and the name ―jerky‖ was given 
birth. This technique of preserving meats assisted the populace to eat food rich in 
protein and energy and was easily available during the lean season. The dominant 
staple food that was consumed by ancient American pioneers and cowboys was jerky 
(Easy Recipe, 2014).With the advancement of time the Americans realised that it is 
possible to prepare more appetizing products by the incorporation of different 
seasonings, eating it out of pleasure relative to need. Jerky is the leading snack food in 
the world due to the different flavours, shapes and various types of meats that have 
been used in the production of the product (Easy Recipe, 2014). 
 
 
7 
 
2.2 Manufacturing Process 
Processing of fresh meat into jerky as a way of prolonging shelf life of a meat product 
started before the origination of cold storage and preservatives. Normally, lean meats 
are used in manufacturing jerky and excess fat are trimmed off, as fat serves as a 
shield that prevent moisture loss, thus causing deterioration as the fat becomes rancid. 
The meats are sliced into very thin strips from 1/8" to 1/4" thick. Meat cut into thin 
strips to a large extent reduce drying time. It is relatively easier to cut frozen meat 
using an electric slicer or knife. Slicers produce consistent sizes of meat strips. Jerky 
that are easy to chew are produced from meats that are cut across the grain (Bell, 
1996). Apart from sliced jerky strips, another common form of jerky is the jerky 
snack stick or snack strip.  First, lean cuts meats are minced using a meat mincer, 
which is then followed by incorporating spices into the minced meat either by hand or 
with a meat mixer. The spiced minced meat is stuffed into jerky gun or cannon to 
produce snack stick or snack strip (―How to make jerky,‖ 2017). 
 
Contemporary manufactured jerky is usually marinated in seasonings or spice rub or 
solution. Historically, as a way of extending the shelf life and introducing taste to 
jerky products, dry cure rub or solution was used. In addition, the ingredient that is 
used also affects the final colour of the product as well as act as an antimicrobial 
agent, which prevents the growth of harmful bacteria (Bell, 1996). Sodium chloride is 
commonly used as the basic preservative for jerky, however, modern marinade 
solutions contains acids such as vinegar and citrus juice which can also destroy 
bacteria(―How to make jerky,‖ 2017). A common curing solution consists of water 
and salt plus sodium nitrite. The salt dehydrates the meat whereas the sodium nitrite 
inhibits the development of rancidity and stabilises the colour. Pink colour of meat 
8 
 
can be improved using sodium ascorbate (Bell, 1996). Fresh meat weight of about 
453.6grams will reduce to 113.4gafter it has been processed into jerky (Nummer et 
al., 2004). 
 
2.3 Marinade 
A marinade is a sauce which is designed to flavour and tenderise meats. Marination is 
a procedure whereby meat is submerged in a marinade sauce which prolongs its 
storage life and improves flavour qualities (Lemos et al., 1999). Acid marinades 
contain   vinegar, lemon juice or wine. Whiles enzymatic marinades are made with 
ingredients such as bromelain from pineapple or papain from papaya (Corriher, 2012). 
In addition alkaline marinade consists of salt and phosphate (Barbut et al., 1989). The 
efficacy of most marinade sauces largely rely on their ingredients that is used (salt, 
phosphates, organic acids, tenderisers, sugar, seasonings and flavourings) (Xiong and 
Kupski, 1999; Smith and Acton, 2001). Soy sauce, worcestershire sauce, teriyaki 
sauce, lemon juice, pepper, monosodium glutamate (MSG) or garlic powder are the 
basic flavourings used in marinades. Sweetness that is added to marinade solutions 
includes sucrose, dextrose, brown sugar and dark corn syrup.  Hickory and onion salt 
are also used to enhanced flavour (Bell, 1996). In order to enhance jerky tenderness, 
tenderising agents such as polyphosphates or papain enzyme can be added. The use of 
these tenderising agents is restricted, because it prolongs the time needed for drying 
(Bell, 1996). Meats are marinated in the refrigerator in order to avoid microbial 
contamination (―How to make jerky,‖ 2017).  
 
9 
 
2.3.1 Functionality of Marinades 
 Ke et al. (2009) reported that a food acidulant such as citric acid is used in marinade 
to enhance water-holding capacity and tenderness of muscle. It controls the activity of 
pro-oxidant metals by acting as achelator. Vinegar is employed in the meat 
manufacturing sector as a decontaminant (Ricke, 2003). Manteuffel- Gross and 
Ternes (2009) stated that ―common house-hold marinating ingredients are vinegar and 
fresh citric juices such as grapefruit, lemon, lime, and orange. Other marinades 
commonly used on game meats are teriyaki sauce, soy sauce, and red wines, alone or 
in combination‖. With regard to alkaline marinade, ―Phosphates used in meat and 
meat products have several functions, especially functions such as the adjustment of 
pH, buffer properties, sequestration of selected cations, changing the ionic charges 
distributions, changing the ionic strength of environment and/or bacteriostatic effects‖ 
(Nguyen et al., 2011). In addition salt in alkaline marinade performs several functions 
such as preventing the growth of bacteria and enhancing meat flavour. Furthermore, 
salt has a great influence on meat ionic strength and can extract myosin from 
myofibrillar structures in meat. According to Knight and Parsons (1988) and Ranken 
(2000), salts could enhance swelling of protein structure but they (on their own) do 
not solubilise much protein‖.  Phosphate removes the link between actin and myosin 
however; it can barely activate proteins on its own (Feiner, 2006). Previous study by 
Froning and Sackett (1985) has shown the combined influence of salt and phosphate 
on meat to reduce weight loss during heating, improving texture and water holding 
capacity. In addition phosphate and salt combine synergistically inhibited Escherichia 
coli growth (Dickson et al., 1994). 
 
10 
 
2.4 Acidic Marinades 
Food additives used to acidified foods are normally studied and used in food 
production. Organic acids used in the preparation of acidic marinades include acetic 
acid, lactic acid, citric acid and wine or fruit juices (Stanton and Light, 1990; Lewis 
and Purslow, 1991; Burke and Monahan, 2003). Soy sauce, acetic, citric, ascorbic, 
and tartaric acids are examples of food additives that can be used to acidify meat 
proteins (Calhoun et al., 1996). In addition they enhance meat flavour and colour. 
 
2.4.1 Tenderisation Action of Acidic Marinades in Meat 
The process through which acidic marinades tenderise meat include many factors 
such as swelling of the meat which result in weakening of structures, increased 
activity of cathepsins and increased  gelatinisation in the presence of heat and low pH 
(Berge et al., 2001; Offer and Knight, 1988).Water holding capacity exerts direct 
effect on meat tenderness. Whiles meat pH value is very vital because it has an impact 
on water holding capacity (Goli et al., 2007), since water-holding capacity differ with 
muscle pH.  Hamm and Deatherage (1960) reported that water holding capacity of 
fresh meat increases quickly as pH decreases below the electrically neutral state of 
muscle (5.1), which increases the relative number of positive charged protein groups. 
Furthermore, muscle pH value higher than 6.0 and lower than 4.0 will cause reactive 
groups that are available to greatly increase its water bind capacity (Gault, 1985). 
Additionally, Rao and Gault (1989) stated that stromal proteins swelled and retained 
moisture when meat was acidified below its isoelectric point, whiles myofibrillar 
proteins swelled and retained it moisture at a pH levels of 4.0 and below. Adding 
positive or negative charges result in repulsion of muscle fibres which creates space in 
which water can be held (Foster, 2004). 
11 
 
Berge et al. (2001) found that meat tenderness was enhanced when organic acids were 
injected pre-rigor and postmortem. The meat pH decreased rapidly to about 5.0 which 
were initiated by the addition of organic acid; however, swelling or moisture content 
increase was not achieved. It can be concluded that cathepsin activity was principally 
responsible for the tenderising effect of the meat. The explanation corresponds with 
the above observation. Similarly, Stanton  and Light (1990) injected bovine muscle 
with lactic acid immediately after slaughter, the lactic acid caused rapid pH decline in 
prerigor meat and increased degradation of perimysial collagen. Injection of lactic 
acid marinade into muscle prerigor achieved both an earlier post-mortem activation of 
muscle cathepsins and accelerated more uniform distribution of acid throughout the 
meat. Also Ertbjerg et al. (1999) confirmed the above report, that lowering meat pH 
favoured increased release and activities of lysosomal cathepsin. Also lysosomal 
activity increased with increased in the concentration of the acid used.  Lysosomal 
cathepsin (B and L) cleave both myofibrillar (Ouali et al. 1987; Mikami et al. 1987) 
and collagenous proteins (Etherington et al. 1974; Mason et al. 1984).  Offer and 
Knight (1988) reported that collagen solubility was achieved when cross-links 
disintegrated. Again Offer and Knight (1988) suggest that ―collagen may be soluble 
through the breakdown of cross-links. Some of these bonds are Schiff base aldimine 
bonds being ruptured easily by pH, heat changes, and denaturing agents‖. 
 
Wenham et al. (1976) and Berge et al. (2001) reported that meat treated with acid 
improved in tenderness within the first few days of marinating. In addition there is a   
slight increase in tenderness when the treated meat is marinated for a longer duration 
(over 21days); this suggest that meat marinated in an acid solution for extended 
period will not result in any distortion of sensory attributes. Ertbjerg et al. (1999) 
12 
 
suggested that cathepsin was responsible for improving tenderness of meat treated 
with acid and marinated for an extended period. 
 
Hutton (1981) and Moeller (1977) revealed that lysosomal enzyme activity decreases 
o
when heated with either a microwave or conventional heat from 40 to 70 C, also 
o o
cathepsin C activity is greater in the soluble and insoluble fraction at 2 C than 37 C‖. 
On the contrary, Lutalo-Bosa and Macrae (1969) observed a higher cathepsin 
o
enzymes activity at a temperature around 40 C and a lower activity as temperatures 
o
increased above 40 C. Temperature is apparently the major dominant factor affecting 
enzyme functionality. Some authors (Miles et al., 1995; Berge et al., 2001) have 
reported that acid marinating weakens connective tissue and cause a decreased in 
o
thermal stability by shifting the denaturation temperature downward by 5-10 C. Lewis 
and Purslow (1991) observed that the influence of acid marinating on connective 
tissue was minimal compared to myofibrillar proteins. Denaturing temperature is 
remarkably less if marinated in acid than in water or salt (Aktas and Kaya, 2001). 
Another study revealed that beef cores marinated in acetic acid at pH 2.5 for 72h 
significantly decreased collagen proteins compared with beef cores marinated in 
phosphoric acid at pH 1.5 for 72h (Oreskovich et al., 1993). This indicates that the 
type of acid used as an effect on meat tenderness. 
 
2.4.2 Antimicrobial Effect of Acidic Marinades 
Organic acids have bacteriostatic and bactericidal properties, however, its ability to 
manifest these attributesdepends on the physical state of the organism and the 
characteristics of the external environment (Davidson, 2001), the type of acid applied, 
amount used and method of application. Efficacy of organic acid could be influenced 
13 
 
by water activity, pH of the food, temperature, oxygen level, fat content and other 
antimicrobials (salt and nitrite).Potency of organic acids is enhanced at a low pH and 
when employed together with other hurdle technologies used to control microbial 
growth (Knipe, 2009; Samelis and Sofos, 2003). Organic acids exhibit their 
antimicrobial property by decreasing the pH in the water phase of foods. Weak 
lipophilic organic acids such as acetic, propionic, sorbic, benzoic exert their activity 
by permeating the cell membrane in the undissociated form to either retards microbial 
development or destroy the microbes by separating and lowering the pH of the 
cytoplasm of the organism (Samelis and Sofos, 2003). Microorganisms die because of 
their inability to maintain a near neutral pH cytoplasm to sustain useful 
macromolecules. The transport of these excess protons requires utilisation of energy 
stored in the cells and can lead to the exhaustion of energy stored in the cells. 
 
The number of investigations carried out for nearly a decade now to ascertain the 
efficacy of organic acids or their salt on the growth of microorganisms in snack foods 
has increased. Derrickson-Tharrington (2001) reported that a significant inactivation 
of E. coli O157:H7 was achieved in beef jerky treated with ascorbic and citric acid 
marinades compared with the control treatment during drying. Similarly, Albright et 
al. (2002) observed a decrease of E. coli O157:H7 count in beef jerky processed using 
four multi–hurdles (immersing in boiling water then marinating, seasoning then 
immersing in hot pickling brine, immersing in vinegar then marinating, marinating 
then immersing in vinegar)and then inoculated with E. coli O157:H7. Also the 
bacteria were not observed in any of the treated samples after one month of storage. 
Naidoo and Lindsay (2010a) reported that conventional organic acids such as apple 
cider vinegar and brown spirit vinegar cannot control the growth of S. aureus. Naidoo 
14 
 
and Lindsay (2010b) again observed that a significant decrease of L. monocytogenes 
was achieved more rapidly in a conventional method (acetic acid dip then spiced) than 
the modern method (acetic acid and spice mixed), whereas the reverse was observed 
for S. aureus. From the above studies it can be deduced that acidic marinades could 
enhance microbial destruction during drying and in storage. 
 
2.5 Enzymatic Marinades (Exogenous Proteolytic Enzymes) 
Consumers of meat are pleased to spend more money on a soft textured meat product 
than tough one (Miller et al., 2001). Therefore it is essential to develop a tenderisation 
technique that is hygienic, fast, uniform, affordable and efficient for the meat 
manufacturing sector. The application of enzymes in meat processing has been 
practiced for many decades to enhance meat products sensory characteristics so as to 
make it easier to masticate and swallow. Enzymes are protein molecules that speedup 
specific chemical reactions. According to Calkins and Sullivan (2007) majority of the 
enzymes do not act on the interior of the meat, making the procedure for applying the 
enzyme on meat to be very crucial. The meat manufacturing sector uses various 
techniques to incorporate tenderising enzymes into meat. The techniques used include 
the following: powder application to the meat surface, immersing the meat in enzyme 
solution or inclusion in marinade, injection brine and pre-mortem injections of the 
protease solutions into the animal prior to slaughter or via post- mortem (Gerelt et al., 
2000). The first two techniques are not good enough, since the enzymes cause 
excessive tenderisation of the meat exterior which leads to distortion of texture, 
whiles the interior is left unaltered (Lawrie and Ledward, 2006).   
 
15 
 
Temperature is apparently the major dominant factor affecting enzyme functionality. 
Majority of the commercial meat tenderisers‘ (enzymes) peak performance is noticed 
o
at temperature range of 50-70 C.  Hence, the exogenous enzymes are more active 
during cooking and to a lesser extend during cool storage (Calkins and Sullivan, 
2007). Hung et al., (2013) examined the effect of Aspergillus oryzae proteases on the 
o
degradation of myofibrillar proteins in Psoas major from pork at 5 C. Samples were 
assessed for duration of one week. Hung et al., (2013) found that Aspergillus oryzae 
extensively degraded titin, nebulin, desmin and α-actinin compared with control 
samples. The degree of titin and nebulin degradation was associated with improving 
meat tenderness (Huff-Lonergan et al., 1995). Rapid denaturation of titin and nebulin 
could possibly breakdown the firm structure of muscle cells (Robson et al., 1997) and 
reduce myofibrillar strength (Horowits et al., 1986).On the contrary, Pietrasik and 
Shand (2008) observed insignificant proteolytic activity of meat treated with 
o
Aspergillus oryzae and Bacillus subtilis stored at temperature of 4 C. The researchers 
concluded that meat treated with enzyme could therefore be stored without any 
negative enzymatic alterations in product attributes. It can also be deduced that 
Bacillus subtilis or Aspergillus oryzae proteinase are of higher quality compared with 
papain. Papain continues its activity at refrigeration temperature even after cooking 
hence increasing the risk of deteriorating sensory attributes of the meat. Similarly, 
Ashie et al. (2002) revealed that papain-treated meat showed slow decreased in 
toughness during refrigerated storage, while Aspergillus oryzae showed no change in 
tenderness. The researchers further observed that Aspergillus oryzae was active 
o o
between 55 C to 75 C during cooking, whiles papain residual activity goes beyond 
o
75 C. It can be concluded that tenderising effect of Aspergillus oryzae proteases arise 
chiefly during thermal process, it is possible to harness the features of Aspergillus 
16 
 
oryzae to treat, convey and distribute several packaged raw meat products. 
Regrettably, plant proteases are of higher quality compared with microbial extracted 
proteases basically due to hygienic health issues such as disease causing effect (Chen 
et al., 2006). Similar to the above observation, Etherington (1984) also found some 
activity of papain treated meat at cold storage temperatures. A meat temperature of 80 
o
C was required for its inactivation. Therefore residual activity can often occur after 
thermal treatments of meat. Foegeding and Larick (1986) stated that papain has 
o
optimal activity at 60 - 70 C; thus this enzyme is most active during thermal 
treatment of meat.  
 
Substrate pH has a significant effect on enzymatic activity. Some enzymes express 
their optimum activity in a more acidic or alkaline medium for protein degradation, 
however, majority of the enzymes operate within the normal optimum pH range of 
meat (Calkins and Sullivan, 2007). Kim and Taub (1991) reported that optimum pH 
was 5.0 for bromelain while Ashie et al. (2002) found that Aspergillus had an 
optimum pH 7.0.Proteolytic enzymes such as papain, ficin, bromelain, Aspergillus 
oryzae and Bacillus subtilis protease have been classified as ―Generally Recognized 
as Safe (GRAS)‖ to improve meat tenderness. Ashie et al. (2002); Gerelt et al. 
(2000); Kang and Rice (1970); Kim and Taub (1991); Takagi et al. (1992) have 
reported that ―each of these enzymes have varying degrees of activity against 
myofibrillar and collagenous proteins‖. 
 
 
 
17 
 
Table 1: Enzymes Classified as “Generally Recognised As Safe” (GRAS) for 
Meat Tenderisation 
Enzyme Type Source Protease class 
Papain Plant Papaya Cysteine 
Bromelain Plant Pineapple Cysteine 
Ficin Plant Figs Cysteine 
Bacillus Protease Bacterial Bacillus subtilis Serine 
Aspartic Protease Fungal Aspergillus oryzae Aspartic 
USDA‘s Food Safety Inspection Service (FSIS) (Payne, 2009). 
 
2.6 Papain 
Papain is recognised in the food manufacturing sector for its activity as a tenderiser 
for meat; weaken the structure rigidity of myofibrillar and connective tissue proteins 
(Aehle, 2007). Azarkan et al., (2003) reported that commercial papain accessible in 
the shopping malls and stores is processed from the latex of the pawpaw plant. 
Papain, chymopapain A and B (EC 3.4.22.6), endopeptidase papain III, endopeptidase 
papain IV and endopeptidase papain omega are some of the proteases that can be 
found in the latex of unripe pawpaw fruit (Carica papaya L.). Papain consists of a 
single polypeptide chain with three disulfide bridges and sulfuhydyl group necessary 
for activity of the enzyme. Additionally, papain molecular weight is about 23,406 Da 
whiles its maximum activity is achieved at optimum pH range of 6.0 to 7.0. The 
enzyme also displays wide specificity, splitting peptide bonds of basic amino acids, 
leucine or glycine. It also breaks down esters and amino acids (IUBMB Enzyme 
Nomenclature, 2009). 
 
18 
 
2.6.1 Myofibrillar and Connective Tissue Degradation by Papain 
Geesink et al. (2011) suggested that addition of exogenous enzyme augment the 
activities of endogenous enzymes to enhance meat tenderness. Several studies have 
confirmed reports of non selective hydrolyse of meat proteins by papain (Foegeding 
and Larick 1986; Miller et al., 1989; Takagi et al., 1992). According to Ashie et al. 
o
(2002) ―papain retained maximal activity even after cooking to 75 C thus increasing 
the risk of both texture and flavour defects‖. Earlier report from Kang and Rice 
(1970) indicated that papain showed greater activity for myofibrillar fraction with 
stronger solubilising activity on connective tissue. In agreement Sullivan and Calkins 
(2010) also reported that papain displayed significant collagen solubility of meat 
muscle than bromelain, ficin, and B. subtilis proteases. Rawdkuen and Benjakul 
(2012) suggested that a higher solubility of meat collagen treated with enzyme is 
probably due to a rise in penetration of the connective tissue, which easily breaks into 
fragments. Furthermore, proteolytic enzyme may also assist in structural 
modifications through action on intermolecular cross-links. Meat tenderness is 
achieved when collagen is solubilised to gelatin. The function of collagen is of 
immense concern, as it is regarded as the main deciding element in the tenderness 
variations among several muscles.Contrary to earlier reports, Wada et al. (2002) 
indicated that papain degrademyosin and actin filaments. Pawar et al. (2003) also 
reported that papain hydrolyses fibrous protein and connective tissue and indicated 
that papain solubilised 15% connective tissue proteins and 60% salt soluble proteins. 
A detailed finding from Istrati (2008) indicated that papain breaks down less 
actomyosin than myosin. Muscle firmness is lost due to proteases degradation of meat 
proteins which result in increase solubilisation of free amino groups and 
hydroxyproline. In addition meat tenderness is enhanced (Fogle et al., 1982). 
19 
 
Furthermore; Istrati (2008) found out that accumulation of free amino acids and non-
protein nitrogen increased proportionally with increased in papain concentration and 
duration of ageing of meat. The formation of free amino acids and non protein 
nitrogen in meat is one way to measure the extent of protein degradation. Doneva et 
al. (2015) concluded that the rate of hydrolysis of meat proteins is contingent on the 
following factors – enzyme type, quantity of enzyme in a solution and treatment 
duration. Thus high dose of enzymes and longer duration of processing results in 
higher hydrolysis of collagen in meat. Higher hydrolysis of meat proteins leads to 
protein loss and deterioration of meat sensory attributes. 
 
2.7 Marinating Techniques and Duration 
A marinade can be in a form of paste, liquid or dry rub. Period for marinating widely 
differs based on the type, cut and size of the meat. Meats such as pork and steak can 
marinate for 24 h or beyond whiles chicken can marinate between 2 h and 24 h, meat 
cut into thin strips marinate more effectively and require shorter marinating time than 
larger strips (Christensen, 2009). 
 
2.7.1 Marinating Methods 
2.7.2 Immersion 
According to Xargayó et al. (2001) ―immersion is the oldest method, consists of 
submerging the meat in the marinade and allowing the ingredients to penetrate the 
meat through diffusion with the passage of time. This method is quite unreliable in the 
meat industry because it does not provide regularity in distribution of the ingredients 
and because it increases the risk of bacterial contamination‖. Young and Yang (1975) 
reported of an improvement in meat tenderness when meat was immersed in papain 
20 
 
solution, however, meat tenderness improved with increased in papain concentration 
from 0.01% to 0.1% concentration. Ashie et al. (2002) confirmed that a higher dosage 
of the enzymes was required for marinating by immersion due to the inability of the 
enzyme to penetrate into the meat as compared to the injection method. On the other 
hand, Gerelt (2000) reported that dehydrated meat dipped for 3 h in a papain solution 
o
and kept at 4 C for 168 h, achieved 80% penetration rate. Both sensory and 
instrumental measurements recorded a decreased in tenderness of the treated samples 
than control samples. Papain fragmentations of myofibrils were observed at 24 h and 
beyond.  
 
2.7.3 Multi-needle Injection Marinating 
Xargayo et al. (2001) stated that ―multi-needle injection marination is perhaps the 
most widely used method because it allows for dosing an exact quantity of brine, 
ensuring regularity in the products and without the time losses involved in 
immersion‖. The procedure involves insertion of a needle or probe into a meat which 
the marinade is then released into the meat and the probe or needle withdrawn; the 
marinade is then uniformly distributed throughout the meat (Smith and Acton, 2001). 
Ertbjerg et al. (1999) reported that beef injected with lactic acid and marinated for 
21days resulted in an increased in the activity of cathepsin. Cathepsin activity 
increased with increased in lactic acid concentration and duration of ageing. Lactic 
acid significantly reduced shear force value. Wheeler et al. (1993) also reported of a 
decreased in tenderness of beef muscle (Longissimus, Semimembranosus and Triceps 
brachii) injected with Calcium chloride for 30 min and 24 h post-mortem. It was 
reported that Calcium chloride did not affect the meat colour at 24 h post-mortem; 
21 
 
however, a slightly colour change was observed after 30 min post-mortem. Indicating 
that duration of marinating has less effect on colour and tenderness of the meat. 
 
2.7.4 Vacuum or Manual Tumbling 
Meat tumbling is normally carried out using a vacuum tumbler, which assists 
marinade solution permeation and enhance colour consistency of meat. Massaging 
and tumbling produce protein exudates (which compose of actin and myosin); which 
support bonding during cooking process. Tumbling exist in two forms, which are 
continuous and intermittent. Intermittent tumbling is used to establish equilibrium 
between maximum tumbling time and marinade permeation time (Hayes et al., 2007), 
whiles continuous tumbling eliminate the period of rest that occurs during the 
intermittent tumbling which results in elastic shrinkage of meat. Although several 
studies have been carried out to outline the benefits of using intermittent tumbling 
(Ockerman and Organisciak, 1978; Plimpton et al., 1991) however, Gillett et al. 
(1982) still suggested that ―continuous tumbling was more effective than intermittent 
tumbling‖. Investigation by Gao et al. (2015) indicated that vacuum continuous 
tumbling marinating treatment improved functional properties and sensory qualities of 
meat compared to vacuum intermittent tumbling marinating treatment. Smith and 
Acton (2001) reported that tumbling enhance products juiciness and slicing 
characteristics, due to the extraction of salt proteins to the meat exterior; which 
promote protein coagulation during thermal treatment to enhance binding properties. 
Furthermore, the protein exudates act as a shield during cooking processes to prevent 
moisture loss in the meat. 
 
22 
 
2.8 Marinade Ingredient Functionality 
There are many varieties of ingredients that are used in the production of different 
flavours of jerky. Commercial jerky available in the markets comes in many flavours 
with different food grade chemicals, additives and preservatives. Commercial jerky 
producers use different ingredients such as salt, sweeteners, monosodium glutamate 
(flavouring agent), garlic, black pepper, paprika, tomato powder, sodium nitrite, 
sodium erythorbate, worcestershire sauce, soy sauce or teriyaki sauce, wine, vinegar, 
citric acid, succinic acid, potassium sorbate (to prevent mould growth), apple juice 
and papaya juice (Ingham et al., 2006). 
 
2.8.1 Spices 
Spices and herbs, added in marinades significantly enhance meat safety and controlled 
or minimised lipid oxidation (Gutierrez et al., 2009). Several studies have been 
carried out for many years to explore the benefit of using herbs and spices to enhance 
sensory attributes and prolong shelf life of foods (Fernandez-Gines et al., 2005). The 
chief purpose of using spices and herbs are the flavour they generate, however, some 
have demonstrated antimicrobial characteristics (Tiwari et al., 2009; Tajkarimi, et al., 
2010). In addition, phenolic compounds which exhibit antioxidant activity have been 
found in many spices and herbs (Sasse et al., 2009). The two main spices that are 
commonly used in cooking to improve the flavour of meat products are garlic and 
onion (Tang and Cronin, 2007). Garlic and onion contain phenolic and sulphur 
compounds and act as antioxidant and flavour enhancer respectively (Griffiths et al., 
2002). Hence, the use of these two spices will probably cover, influence or enhance 
odour/flavour of meat product sensory attributes. 
 
23 
 
Yang et al. (2011) observed that 0.5% onion included in irradiated raw minced meat 
exhibited antioxidant effect, but had no influence on colour of irradiated raw minced 
meat but generated a weak aroma. On the other hand, a combination of garlic and 
onion generated a greater quantity of sulphur compounds in non-irradiated ground 
beef, but quantity reduced and profiles altered after irradiation. Whiles 0.1% garlic 
inclusion generated very strong garlic aroma in irradiated raw ground beef. Similarly, 
Sallam et al. (2004) also found that incorporation of fresh garlic or garlic powder in 
sausage products generated no strong flavour and also exhibited antioxidant and 
antimicrobial activity which prolonged the shelf life of the sausage for up to 21 d. 
Deducing from the results of the above authors garlic and onion could be used to 
prolong the shelf life of meat products by acting as natural antimicrobials and 
antioxidants in meat products. However, their effectiveness depends on the quantity 
used. 
 
2.8.2 Salt (sodium chloride) 
Lazarides et al. (1995) stated that salt is the major essential ingredient used in the 
production of dried meat products.  Historically, it has been used for years to preserve 
meat; salt has the potential to act as a desiccant but at lower level could elevate 
moisture content in a meat product. Salt contains chloride anion which extracts 
myofibrillar proteins during processing. Small amount of salt about 1.4% or 1.75% is 
needed for appreciable product bind and quality in normal and less fat meat products 
(Ruusunen and Puolanne, 2005). Salt is said to associate with taste buds in aqueous 
solutions including saliva to generate a taste response (Spielman, 1990). Research has 
revealed that inclusion of salt elevates the degree of salivation (Neyraud et al., 2003) 
and could explain the decreased taste observed in products with low salt mixtures. 
24 
 
Moreover, salt improves meat product flavour and over palatability (Doyle and Glass, 
2010). Whiles too much salt generates harsh flavour; too little salt will cause rejection 
of a meat product (Martin, 2001). Salt act as a desiccant that enables it‘s to exhibit 
antimicrobial activity in processed meat products. The preservative effect of salt is 
achieved due to the presence of chloride which exerts this control (Taormina, 2010). 
Salt can effectively inhibit microbial growth in combination with other hurdle 
technologies such as ingredients used, pre - treatments and proper storage conditions 
(Doyle and Glass, 2010). Some bacteria can tolerate the presence of higher 
concentrations of salt; an example is Staphylococcus aureus that can survive in a meat 
product containing 20% salt or beyond (Doyle and Glass, 2010). 
 
Beside the good attributes of salt, it can also act as a pro-oxidant in processed meat 
product by elevating the degree of metmyoglobin formation (Chem et al., 1992) and 
increased lipid oxidation (Andersen and Skibsted, 1991). Other contaminants such as 
metal ions in processed meat products can expedite the rate of oxidation (Townsend 
and Olson, 1987). The use of sea salt could pose such a challenge; it is of necessity to 
use high quality salt in order to avert such problems. 
 
2.8.3 Soy Sauce 
Soy sauce is well known throughout the world, it has a low pH value due to formation 
of organic acids derived from the main ingredients (soybean or wheat) during 
microbial fermentation (Choi et al., 2000). Soy sauce has an intense flavour that is 
used to mask objectionable flavours emanating from meat obtained from animals such 
as venison and wild boar.  Additionally, it provides acidity, salt flavour and colour to 
the meat. Soy sauce contains a multitude of acids (lactic acid and pyroglutamic acid) 
25 
 
with lactic acid and pyroglutamic acid as the chief acids but lactic acid is the 
predominant acid found in soy sauce. Due to the multitude of acids it contains it will 
be difficult to determine the exact acid that cause improved tenderness in meat when 
it is used as the main acidulant in marinades. Other lesser organic acids found in soy 
sauce are in order of commonness, acetic, formic, citric and succinic acids. 
Additionally, it is also high in salt (18%) (Manteuffel-Gross and Ternes, 2009). Kim 
et al. (2014) observed significant enhancement in tenderness and colour of chicken 
breast treated with soy sauce. Lim et al. (2013) also reported that beef jerky treated 
with soy sauce had higher moisture content, lower salt concentration, enhanced 
colour, flavour and tenderness compared with control products. This shows that soy 
sauce has a positive effect on meat products sensory attributes. 
 
2.8.4. Sweeteners 
According to Martin (2001) different types of ingredients can be used as sweeteners 
to impact positive effect on meat flavour, colour quality and microbial development. 
White sugar, brown sugar, dextrose and corn syrup are mostly used in meat 
processing, additionally, honey, maple syrup, and molasses can as well be used to 
generate distinct flavour attributes (Pearson and Gillett, 1999). The basic role of 
sweeteners in processed meats is to reduce the harsh flavour of salt (Townsend and 
Olson, 1987).  Additionally, flavour and colour are generated by Maillard browning 
reaction of sugars during heating processes (Pearson and Gillett, 1999). Maillard 
reaction is the voluntary interactions between reducing sugars and amino groups of 
proteins (Ajandouz et al., 2008). The reaction is intensely dependent on pH, time and 
temperature (Quintas et al., 2007; Ajandouz et al., 2008). Kwak and Lim (2004) 
reported of the browning intensity of lysine which reacted with five reducing sugars, 
26 
 
the sugar reactivity was in the order of xylose higher than arabinose, glucose, maltose 
and fructose, respectively. Similarly, Wongwiwat and Wattanachant (2014) 
investigated browning intensity of four sugar types incorporated in dried chicken meat 
product. It was reported that product prepared with fructose caused darker brown 
colour compared to sucrose, lactose and sorbitol. Product prepared with sucrose had 
the highest sensory score in glossy attribute. 
 
Also heat treatments could cause changes in functional characteristics of proteins.  
High temperatures can cause modifications in proteins which will affect the food 
texture by causing conformational changes or aggregation (Arakawa et al., 2001). 
Sugar can act to stabilise proteins to heat denaturation (Rich and Foegeding, 2000). 
Allen et al. (2007) observed a correlation between water activity and moisture content 
and Han et al. (2007) also suggested that sugar can be added to meat product during 
processing to assist in decreasing water activity of the product. Both sugar and salt 
exhibit similar antibacterial activity in processed meat products by elevating ionic 
strength and reducing water activity (Jay, 2000). However, the percentage of sugar 
incorporated into processed meat products without additional hurdle is too small to 
inhibit microbial growth (Pearson and Gillett, 1999). 
 
2.9 Preservation of Meat 
Meat and food preservation was an important tool that assisted ancient farmers to 
increase their produce and prolong food supply by retarding spoilage. Also meat 
preservation became imperative for conveying meat over extended distances without 
deterioration of sensory attributes and nutritional properties after the establishment 
and fast expansion of grocery stores and shopping malls (Nychas et al., 2008). The 
27 
 
objectives of meat preservation techniques are to reduced oxidation, prevent microbial 
and enzymatic deterioration. Historically, foods have been preserved by salting, 
drying and smoking, methods that have been enhanced by scientific, techniques. In 
addition, early hunters use to freeze foods. The methods used for the preservations of 
foods were based on the surrounding environment (Wentworth, 1956). Areas with low 
humidity depended on the sun for drying foods. Meat was later dried and smoked on 
fires. Freezing, as a method of preservation, was restricted to geographical areas with 
cool weather. Salting of meat was an efficient preservative method that was carried 
out in Arabian Peninsula and in coastal regions by early hunters (Wentworth, 1956; 
Binkerd and Kolari, 1975).  
 
Currently the methods of meat preservation include controlling of temperatures, water 
activity, use of chemical or bio-preservatives and a mixture of the various methods 
(Bagamboula et al., 2004; Zhou et al., 2010). Although, there are several preservation 
techniques, drying of food is among the best ancient and effectual technique 
developed (Hotchkiss and Potter, 1995).With the development of scientific technique 
in meat preservation, some conventional meat products (fermented sausages, dry-
cured hams, pastrami, jerky, Bresaola (Italy), Biltong (Southern Africa), Odka 
(Somalia), Kuivaliha (Finland), Qwanta (Ethiopia), Kilishi (Nigeria), etc.), in which 
drying is one of the chief processes, are still manufactured in great quantities due to 
their distinct and approved flavour (Rahman et al., 2004). All over the world, 
techniques and recipes used for meat preservation varies among cultures. Meats that 
are salted, cured, dried or smoked can be preserved with or without the inclusion of 
spices or fruits.  Dried meat from animals such as cattle, turkey, horse, camel, sheep, 
28 
 
pig, and ostriches are still consumed to this day. Odka, biltong, qwanta and Kilishiare 
some of the popular dried meat products that can be found in Africa (FAO, 1990). 
 
2.9.1 Odka 
Odka is a traditional dry meat product of the people of Somalia. Odka is made using 
lean beef which is cut into larger strips. The cut strips are rubbed with salt and then 
sun dried for four to six hrs. The dried product is then cut into small strips and cook in 
oil. The cooked product is spiced, sauced and further dry in the sun. The product is 
then masked with oil and stored in an air tight closed container. The product can be 
kept for more than one year (FAO, 1990). 
 
2.9.2 Qwanta 
Qwanta is a meat product from Ethiopia, is made using lean beef. The meat is cut into 
strips of about 20 to 40cm long. The strips are then sauced using 50% pepper, 25% 
salt and 25% other spices. The meat is hung on wire and air dry for 24 to 36h in a 
room. It is further dried on fire and followed by frying using butter. Additional drying 
is carried out after the frying. The product is then stored in an air tight container 
(FAO, 1990). 
 
2.9.3 Biltong 
Biltong is a traditional salted meat product of the people from Southern Africa. The 
product is produced using meat made from cattle or antelope. The meat is cut into 
strips of about 1 to 2 cm long. It is then rubbed with salt and pepper which are the 
main ingredients, however, other additives and preservatives may also be used to 
enhance colour, flavour and taste as well as inhibit microbial growth. The meat strips 
29 
 
is then cured for some hrs but not more than 12 h. In order to add flavour to the 
product and also inhibit fungi growth, the meat strips are blanched in a mixture of 
warm water and vinegar (about 10:1). The meat strips are then sun dried for a day and 
then kept under a shade for the remaining drying period. The product is done when 
the interior is soft, moist and red in colour with a hard brown outer layer (FAO, 
1990). 
 
2.9.4 Kilishi 
Kilishi is a dry meat product from Nigeria. Lean meat from sheep, goat or cattle can 
be used to manufacture kilishi. The meat is sliced into sheets of less than one metre 
for fast drying. The dried meat is then marinated in sauce consisting of peanuts, spices 
and salt. It is then further dry in the sun. After drying the meat is roasted in oil and 
then consumed or stored for several months (Igene et al., 1990; Musonge and Njolai, 
1994). 
 
2.10 Drying of Meat 
Keey (1975) defined drying as any process by which water is removed from a 
substance. It can also be said to be the removal of volatile substances by heat from a 
mixture that yields a solid product. The principal volatile substance is water, and 
water is the constituent whose removal is sought. Some of the factors that control 
drying of food products include air temperature, relative humidity and air velocity. 
Three distinct phases are involved in the drying of food products; first is the induction 
phase, the induction phase marks the beginning of the drying, with rapid elimination 
of water from the meat. The second is the constant rate phase, the constant rate phase 
correspond to the constant evaporation of water from the outer layer of the meat. 
30 
 
Lastly, the third phase is the falling rate phase, the falling rate phase relate to the most 
arduous elimination of water because of its slow diffusion to the outer surface of the 
meat (Hui et al., 2012). Fat in meat acts as a shield which helps to retained moisture 
during cooking. The fat delays drying by preventing water transfer from the exterior 
to the surface of the meat. The drying rate decrease when fat content is high (Hui et 
al., 2012). Meat moisture content is decreased when there is evaporation of water 
from the outermost layer to the surrounding air and continuous migration of water 
from the innermost layer to the outermost layer of the meat. Continuous decrease of 
moisture content cause a conformational change in the shape of the meat starting from 
small, thin and to some extends shrinkled or wrinkled meat product. The texture also 
alters from soft to slightly tender to tough (Arason, 2003). Furthermore, high quantity 
of fat in meat interacts with high temperatures during drying and in storage which 
influences oxidation and hence may affect the palatability of the product. Lean meat is 
recommended for the production of jerky in order to minimize undesirable changes 
due to fat oxidation (FAO, 1990). 
 
2.10.1 Methods of Drying Meat 
Jerky processing involves the use of different drying techniques. Some of these drying 
methods include natural drying, vacuum drying, freeze – drying, hot and cold air-
drying (Edward and Pauline, 1965; Labelle and Moyer, 1966; Holdsworth, 1971; 
Karel et al., 1978; Kim, 1990).The two basic types of meat drying methods include 
natural or traditional drying and artificial heat source drying. 
 
 
31 
 
2.10.2 Natural or Traditional Drying Method 
The traditional drying of meat involves the use of natural conditions such as sunshine 
and air circulation. The two drying conditions clearly differ based on the degree of 
effect of the solar energy. These drying methods are the sun drying and solar drying 
and are delineated hereunder. 
 
2.10.3 Sun Drying 
Traditionally, the main drying method is called sun drying, distinguished by direct 
solar radiation and natural air circulation on the product. Meat pieces are cut into 
strips or flat leaf-shaped pieces. They are then hang on lines in the open air or spread 
on wire mesh or tray. Specifically, the meat is sometimes blanched in about 14% salt 
solution to prevent microbial and insect attack. For fast and simple preservation of 
excess meat that cannot be consumed instantly, the sun drying method can be 
performed at the farm level (FAO, 1990). However, due to contamination from the 
environment and lack of stable heat source FSIS (2011) do not recommend the use of 
natural drying for making jerky. Furthermore, sun drying is time consuming and 
difficult to control moisture contents (Lee and Park, 2004). 
 
2.10.4 Solar Drying 
In the rural settings commercial meat processors use advanced solar drying systems. 
Contrary to sun drying where there is direct contact of the sun on the meat, solar 
drying uses indirect solar radiation. The concept of the solar drying method is to 
gather solar energy by heating-up the air volume in solar collectors and conduct the 
hot air from the collector to an attached enclosure, the meat drying chamber. Here the 
products to be dried are laid out. In this closed system, consisting of a solar collector 
32 
 
and a meat drying chamber, with this system there is no direct contamination from the 
environment (FAO, 1990). 
 
2.11 Artificial Heat Source 
FSIS (2011) reported that hot air-drying is an example of an artificial heat source 
which is popularly used in the meat processing plants and is carried out by placing 
food in either a warm oven or a food dehydrator. Labelle and Moyer (1966) and Kim 
(1990) also reported that hot air drying method is effective in lowering moisture 
content which helps to prevent microbial growth and dries products uniformly. 
However, the authors again mentioned that besides the good attributes of the hot air 
drying system, the method deteriorate the sensory properties of meat products through 
case hardening and lipid oxidation. This change in sensory attributes occurs as a result 
of rise in drying time and temperature. Other drying methods involving the use of 
artificial heat sources include smoke house drying, oven drying, freeze drying, 
microwave drying and dehydrators. 
 
2.11.1  Smoke House Drying 
The use of smokehouse as a means of drying meat is probably as old as open air 
drying. The jerky strips are hanged on racks and smoke circulates around the meat 
surface (Bell, 1996). Smoke impact desirable distinct flavours to food. Additionally, 
smoke produces compounds that have a bactericidal effect on microbes (Poligne et 
al., 2001; Arboix, 2004). Although not basically used to decrease the moisture content 
of the food, the heat affiliated with the production of smoke act as a desiccant (Cohen 
and Yang, 1995). This gradual cooking method keeps the final product soft. 
 
33 
 
2.11.2  Oven Drying 
Gas, electric and convection ovens are the most commonly used devices for 
producing jerky. Ovens heat up the surrounding air, but unlike the convection ovens, 
they do not circulate it. As a result, jerky dried in an oven varies a great deal from one 
type of oven to another and exhibits more of a cooked flavour compared to the jerky 
dried in a dehydrator. Also, if the temperature of the oven is too high, jerky becomes 
tough, has a burnt flavour, a mealy texture and is more brittle than when dried in a 
dehydrator (Bell, 1996). 
 
2.11.3  Freeze Drying 
Sublimation and desorption is the procedure used to freeze dry meat products. 
Sublimation converts a product from ice directly into a gaseous state without 
changing into liquid. Sublimation happens when the vapour pressure and the 
temperature of the ice surface are below the triple point of water (4.58 mmHg, 0°C). 
Freeze drying was first introduced in the early 1900‘s as a way of preserving high 
quality biological materials such as human serum (Irzynic et al., 1995). Freeze dried 
products have a distinct characteristics such as high structural firmness, high 
rehydration capacity, low density and good sensory properties (Hui and Yiu, 2004). 
Microwave and dehydrators are also used in drying jerky. 
 
Literature abounds on the influence of the various drying methods on meat products 
quality. Lim et al. (2012) evaluated the influence of various drying methods (hot air, 
shade and sun drying) on the physicochemical quality and microbiological safety of 
beef jerky stored under room condition. It was reported that regardless of the cooking 
techniques used in drying the products, moisture content and water activity (aw) 
34 
 
reduced with increased storage time. Also shade-dried jerky showed higher water 
activity compared to the others. Additionally, hot air-dried jerky was tough compared 
with sun-dried or the shade-dried jerky. The total plate count (TPCs) was also high in 
naturally dried jerky than hot-air dried jerky after storage for 20d. With regard to 
sensory attributes, naturally dried jerky showed improvement in attributes than the hot 
air-dried jerky. In conclusion, although natural drying methods are more prone to 
microbial contamination than hot air-drying, however, desirable sensory attributes are 
produced. Recent report by Talib et al. (2014) also found a higher microbial count in 
meat dried using hot air oven compared with solar and sun drying method. In 
addition, solar drying method also recorded a lower microbial count compared with 
sun drying. Nayar et al. (2014) also observed significantly higher water activity, 
moisture content, fat content and pH in hot air oven drying products than microwave. 
Meat colour and microbial quality were also reported to be significantly higher in 
microwave products than in hot air oven. In addition all sensory attributes were higher 
in hot air oven samples than microwave with significant difference in flavour and 
overall acceptability. Microwave drying was found to cause an uncontrolled drying 
with development of burnt flavours which resulted in lower sensory scores and 
reduced acceptability than hot air oven. The low sensory attribute scores in some of 
the above drying methods especially hot air oven drying, was probably due to 
excessive drying and loss of moisture in meat caused by high temperature during 
drying. In meat drying processes, both shorter and longer duration could cause 
denaturation and coagulation of meat proteins that may influence meat texture 
yielding products that could be described as either too tender or too tough (Konieczny 
et al., 2007). The natural drying method with high microbial count was due to low 
drying temperature (FSIS, 2011; Park and Park, 2007).  Faith et al. (1998) observed 
35 
 
that combination of low temperature and longer drying time could efficiently reduced 
microbial count to at least 5 Log CFU/g. 
 
2.12 Rehydration Rate 
According to An et al. (2012) rehydration is a procedure which is aimed at reinstating 
the attributes of a raw material when the dehydrated material comes in contact with 
water. Rehydration is usually done by submerging dried material in water (Garcia – 
Pascual et al., 2005). Rehydration may be regarded as a measure of the degree of 
damage a food substance sustains during drying and treatment before drying 
(McMinn and Magee, 1997). The magnitude of rehydration depends on the level of 
structural and cellular disruption (Krokida and Marinos – Kouris, 2003). Lewicki 
(1998) reported that rehydration properties of dried food materials are used as a 
quality index and show whether physicochemical alteration happened during the 
drying process due to process conditions, pretreatments and sample constituent. It has 
been observed that the quantity of water absorbed is equivalent to swelling of the 
biological materials. The ratio between the dry material weight and water volume 
differs from 1:5 to 1:50; temperature of rehydrating water is from ambient 
temperature to hot. Time of rehydration differs from 2min to 24 h (Lewicki, 1998).  
 
2.13 Microbiology of Meat and Meat Products 
Meat the muscle tissue of slaughter animals consist of water, proteins, lipids, minerals 
and a small amount of carbohydrates. Due to the rich nutritional composition of meat 
and meat products they are liable to quality declination (Jay, 2005). The quality 
declination is due to physicochemical and microbial changes. Deterioration starts 
soon after blood draining, resulting in microbial and physicochemical changes. The 
36 
 
animals hide/skin and gastrointestinal tract (gut) are the major contamination points. 
Fungi mould and bacteria are the three commonly found microorganisms in meat 
products. Bacteria thriving in meat could be aerobic, anaerobic or facultative. 
According to Romans et al. (1994) organisms of concern affiliated with the 
contamination of meat include Salmonella, Escherichia coli, Campylobacter jejuni, 
Listeria monocytogenes and Staphylococcus aureus. On the other hand, those 
associated with the contamination of jerky products include Salmonella sp., 
Staphylococcus aureus and Escherichia coli O157:H7 (Calicioglu et al., 2002, 2003; 
Ingham et al., 2005). 
 
2.14 Food Safety Concerns of Jerky 
The method of jerky production either from whole muscle or restructured ground 
meat varies from the production of other snack meat products because thermal 
treatments is used to achieved the required product attributes and shelf safety. The 
dehydrating step may decrease the process lethality against disease causing 
organisms, however, outbreak of food borne diseases have been connected to the 
eaten of jerky (CDC, 1995; Keene et al., 1997; Eidson et al., 2000). Many outbreaks 
of microbial infections demanded an upgrade of food safety measures and processing 
techniques for jerky. USDA - FSIS (2004) recognized stages in commercial jerky 
processing where producers require improving current practices.  
 
First, because jerky may not be sufficiently heat treated to achieve the lethality 
performance criteria, use of moist cooking was suggested as an option.  A relative 
humidity beyond 90% should be sustained throughout the heating process by using an 
enclosed oven or steam injection. However, adding humidity to the processing of 
37 
 
jerky is uncommon for most jerky producers. Also, some jerky manufacturers may not 
be able to manage humidity well in the smoke house.  
 
o
Secondly, USDA - FSIS (2004) suggested cooking of meat to 71.1 C before drying. 
Harrison and Harrison (1996) found a >5 log cfu/g decrease of E.coli O157 and 
Salmonella and  >4 log cfu/g decrease of L. monocytogenes after thermal treatment at 
o o
71 C and no detection of these microbes after additional drying at 60 C, however, 
preheating meat and or drying jerky at high temperatures for prolonged duration may 
result in a product that varies from conventional jerky and decrease the level of 
acceptability (Calicioglu et al., 2002). 
 
Other authors have reported that using marinade in jerky processing may increased 
the log reductions of pathogens observed. Harrison et al. (1997) found that 
Salmonella and Listeria levels decreased to about 1.0 log cfu/g in marinated than non-
marinated samples during the initial stages of drying. Borowski et al. (2009) also 
found that marinades seasonings can have an effect on the decrease in total population 
of disease causing microbes. Several studies have evaluated the efficacy of drying 
treatments and index (time, temperature), Holley (1985) reported of 15% decrease in 
o
S. aureus inoculated on a jerky after dehydrating for 8h at 68 C, additional 5% 
decrease was recorded after one week of storage. This however, contradicted the 
report by Keene et al. (1997), where viable E. coli O157:H7 were retrieved after 
o
drying whole venison strip jerky 10 hrs at 62.8 C. 
 
Also, the use of chemical intervention approaches have been studied widely, 
Calicioglu et al. (2002, 2003), observed >4 log cfu/g decrease in L. monocytogenes 
38 
 
and no survival of Salmonella or E.coli O157 when beef strips were dipped in 1% 
o
Tween followed by 5%  vinegar before marinating and drying at 60 C for 10h. 
Similarly, Yoon et al. (2006) also reported that 5% vinegar improved pathogen 
reductions. Additional variation that can be recommended in jerky manufacturing is 
the implementation of a post drying thermal treatment. Borowski et al. (2009) 
reported of 3 log cfu/g decreases in Salmonella and E.coli O157when jerky was post 
o
dried at 135 C/10min. After an expansive analysis of the microbial control in ready to 
eat meat products, the United States Department of Agriculture (USDA) reconsidered 
the measures for these shelf staple food products, which is found in Food Standards 
and Labelling Policy Book (USDA - FSIS, 2004).The new standards recommend 
having at least moisture to protein ratio of ≤ 0.75:1 and water activity of not beyond 
0.85 to ensure the safety of jerky products. However, the USDA - FSIS (2004) 
recommended that critical water activity limit for jerky, which is in contact with air, 
be ≤ 0.70, as mould growth is seized at this water activity level. 
 
2.15 Principles of Preservation of Shelf-Stable Dried Meat Products 
Basically, the word ―shelf stable products‖ refers to products that can sustain their 
desirable sensory attributes without the need for refrigeration. Usually, such products 
are stored under ambient condition. This shelf-stability is usually based on the quality 
of the packaging material to control rancidity and potential fungi development. The 
shelf life for these products is often defined for satisfactory quality, not stability 
because the stability has been catered for in the manufacturing process. The shelf life 
of the product is described as the time the particular product can be stored under 
précised conditions that maintains desirable sensory attributes. Shelf-life is regulated 
39 
 
by two types of spoilage: microbiological (spoilage) and chemical (oxidation) (Wilson 
et al., 1981). 
 
2.16 Shelf-Stability and Hurdle Effect 
Shelf-stability is due to a collection of factors, commonly referred to as the ―hurdle 
effect‖. The engagement of these factors affects particular microbes and chemical 
reactions. Managing the many factors and their associations increases the overall 
impact and attain shelf-stability. Scientific food preservation techniques are often 
categorized into three types: 1. prevention/elimination of contamination e.g., 
decontamination of raw materials (steam treatment and organic acid washes of 
carcasses, irradiation of spices), aseptic processing 2. Inactivation of microorganisms 
e.g. heat (pasteurisation and sterilisation), high pressure processing 3. Gradual or 
complete inhibition of microbial growth e.g., low temp, water activity, redox 
potential, pH or preservatives (Beauchat, 1981). 
 
The most basic factors connecting with the safety or shelf-stability in dried meat 
products are water activity, pH, time/temperature/relative humidity, salt/brine strength 
and microflora types (Sumner and Jenson, 2011). Over the total range of products, 
water activity is the major essential factor causing shelf – stability in dried meat 
products; that is if diseased causing microbes are still alive and the product is debased 
(Beauchat, 1981). Protection of food from microbial contamination is directly affected 
by the water activity. Ghaly et al. (2010), defined water activity (aw) as ―water which 
is not bound to food molecules and can support the growth of microorganisms. It 
represents the ratio of the water vapour pressure of the food to the water vapour 
pressure of pure water under the same conditions‖. The growth of microorganisms is 
40 
 
at its peak when water activity is at a range of 0.98-0.99 and growth arrested at water 
activity <0.90. At a water activity 0.6 of yeasts and moulds can thrive (Ghaly et al., 
2010). Most bacterial pathogens cannot tolerate low water activity, Staphylococcus 
aureus, reportedly will not develop aerobically at water activity of 0.85 (Jay, 1992) or 
anaerobically at water activity of <0.88 (ICMSF, 1996).To attain shelf stability, 
United State Department of Agriculture (USDA - FSIS,2005) standards request 
products labelled as jerky to have moisture to protein ratio (MPR) of 0.75:1 or lesser 
and a water activity of  <0.70 for product in contact with air, which is low enough to 
arrest mould growth. It is possible mould will thrive at water activity level greater 
than 0.70. Hence, a combination of hurdles should be used in a product with water 
activity greater than 0.70 to arrest mould growth. Some recommendations are: 
vacuum package, modified atmosphere package (no oxygen in mixture), oxygen 
scavenger, potassium sorbate spray (3oz/gallon) applied post-drying. Ingham et al. 
(2006) suggested that jerky with a water activity greater than 0.85 should not be 
stored under ambient condition; whiles products to be stored in oxygen free packaging 
should not exceed a 0.88.   
 
Beside water activity a product pH is the next most vital factor in shelf stability of 
dried meat product. Suppressing the growth of microorganisms by pH is based on 
many factors, including the type of acid and the temperature. Generally, the minimum 
pH for E. coli O157:H7 nearer to 4.4, but it will thrive well at lower pH values, 
especially if refrigerated (Adams and Moss, 1995). Microbiological minimum or 
maximum limits for growth are basically dependent on temperature, water activity, 
pH or the presence of preservatives (Adams and Moss, 1995). In ready to eat products 
especially dried meats, the environmental conditions are hardly favourable for 
41 
 
microbial growth, however, a combination of hurdles or preservatives present 
becomes an added advantage. The hurdle impact happens when the mixture of 
inhibitors is more restrictive than single inhibitor (synergistic effect). The most vital 
hurdles in food preservation are: high temperature, low temperature, reduced water 
activity, increased acidity, reduced redox potential, preservatives and competitive 
micro flora. Since shelf-stable dried meats products are not sterilised or pasteurised 
and as well stored under ambient condition, the last five hurdles mentioned above are 
of primary importance (Wilson et al., 1981).  
 
2.17 Packaging 
The basic principle of packaging is to retain the acceptable qualities of a product and 
also assure the safety until it reach the consumer at the final point of consumption 
(Kropf, 2004). Although most dried meats are shelf-stable with respect to food safety 
(due to lower water activity and pH), a correct packaging system is essential for 
microbial (Jay, 2005) and chemical shelf-stability. Mostly, the products are packaged 
under vacuum or modified atmosphere where oxygen is removed. Ingham (2006) 
suggested the use of either vacuum-packaged or an oxygen-scavenger inserted in the 
package along with the jerky product and the bag then sealed under air. These 
scavengers are responsible for the elimination of remnant oxygen that may still be 
present after packaging. All jerky products should be inspected and seal secured when 
packaged under oxygen-free conditions. The technique used to reduce oxygen or 
altering food package or chamber atmosphere by flushing different gas mixtures of 
CO2, N2 or O2 is known as modified atmosphere packaging (MAP) (Phillips 1996; 
Jay, 2005). Modified atmosphere packaging comprise of vacuum packaging, 
controlled atmosphere packaging (CAP) and modified atmosphere packaging systems 
42 
 
or dynamic modified atmosphere packaging (Kropf, 2004; Phillips, 1996). Phillips 
(1996) described some of the packaging materials used for modified atmosphere 
packaging, including polyvinylchloride (PVC), polyethylene terephthalate (PET), 
polyethylene (PE), and polypropylene (PP). The chief gases that are utilised in 
modified atmosphere packaging are O2, N2and CO2. These gases are utilised in 
various quantities and mixtures based on the nature of the commodity and the 
requirement of the manufacturers and consumers (Phillips, 1996). However, the final 
selection is based on the type of microflora ability to thrive on the product, the 
susceptibility of the product to O2 and CO2 and the need to stabilise product colour.  
On the other hand, vacuum packaging is a type of packaging in which air is 
eliminated prior to sealing. It is a form of modified atmosphere packaging because the 
usual air composition has been changed. Vacuum packaging of meat products affords 
a lot of advantages such as prolonged shelf-life, decreased weight or moisture loss, 
assists in controlling rancidity, inhibits spoilage bacteria growth and stabilise food 
colour (Jay, 2005).  
 
Many research works (Singh et al., 2011 and Xiao et al., 2011) have been carried out 
on the effect of the various method of packaging on processed meat stability. Ingham 
et al. (2005) reported of a reduction in S. aureus count from1.0 – 2.6 log to 3.2 – 4.5 
log CFU in one month, when a product containing a water activity of 0.68 – 0.82 was 
vacuum packaged. Also Choi et al. (2007) reported of higher total plate count in jerky 
product stored in plastic compared to samples in vacuum packs.  Water activity was 
higher in samples in vacuum packs compared with that of plastic packs. Meshram et 
al. (2014), also observed that sensory attributes deteriorate with time in both aerobic 
packaging and modified atmosphere packaging (nitrogen), however, the sensory 
43 
 
attributes decline faster in aerobic than modified atmosphere packaging when stored 
for a extended period. Kim et al. (2014), also obtained a similar result, however, 
tenderness improved in vacuum pack samples than modified atmosphere packs. While 
water activity, pH and moisture content were significantly lower in modified 
atmosphere packs compared with that of vacuum packs. Sharma and Nanda (2002) 
reported of a decrease in flavour of chicken chips that were vacuum-packaged and 
stored at ambient temperature. Change in meat flavour during storage is due to lipid 
oxidation (Aguirrezábal et al., 2000). From the above authors results it can be 
concluded that irrespective of the packaging methods sensory attributes of meat 
deteriorate with time. 
 
2.18 Eating Qualities of Meat 
Meat eating qualities including tenderness, juiciness and flavour are regarded the 
major essential meat palatability traits by consumers (Lawrie and Ledward, 2006; 
Smith et al., 2008). Similarly, Albright et al. (2000) reported that the most essential 
sensory characteristics of jerky are texture, colour and flavour, which are determined 
by the raw ingredients and many technological factors.   
 
Flavour is an essential eating attribute when meat products are served (Behrends et 
al., 2005). Raw meat has little or no aroma and only has a blood – like taste, hence 
meat flavour is heat derived. Huang and Ho (2001), reported that meat flavour 
constituents are formed from the heat degradation of compounds mostly contain in 
meat such as fats, proteins and carbohydrates and thermal processes that essentially 
impact overall meat flavour. In meat, two reactions that occur in the cooking process 
are largely responsible for flavour development: Maillard reaction and oxidation of 
44 
 
meat. Maillard reaction and the oxidation of lipids during thermal treatment cause to 
the development of meat flavour.  The Maillard reaction, which happens between 
amino compounds and reducing sugars, is one of the major vital channels for the 
production of flavour compounds in cooked meat. On the other hand, lipids can break 
down via oxidation of fatty acids to give volatile odour compounds that can be either 
desirable or undesirable (Mottram, 1998). During storage, autoxidation of lipids can 
happen to generate a ―rancid odour‘‘ in raw meat or a ―warmed-over‖ flavour in 
cooked meat (Farmer, 1994). A major quality spoiler of stored foods is attributed to 
off-odours and flavours of oxidative rancidity (chemical change in an unsaturated 
bond of a fat or oil). The fat component of meat is believed to contribute to the 
species specific flavours associated with beef, lamb and pork (Calkins and Hodgen, 
2007). In addition, Melton (1990) determined that meat flavour is influenced by fatty 
acid composition. Smith et al. (1974) reported that chevon was not significantly 
different from beef or lamb in flavour desirability when oven-baked rib or loin 
samples were evaluated by untrained panelists. Factors such as age, diet, breed and 
sex may also influence the odour and flavour of mutton or chevon (Shahidi, 1994). 
The dissimilarities between different muscles of meat, preparation methods and 
cooking conditions may also influence the production of aroma compounds (Fu and 
Ho, 1997; Priolo et al., 2001). These technologies as well as marinating can be 
combined and their use can add value to meat products. 
 
The chief factor which contributes to the overall eating quality and consumer 
fulfillment of meat is the tenderness (Mori et al., 2001). Tenderness is defined as the 
ease of chewing, which involves the initial ease of biting through, the ease with which 
the meat breaks into pieces and the quantity of remnant left after chewing  
45 
 
(Lawrie, 1998). Meat tenderness is influenced by pre slaughter factors (species, breed, 
age, sex, feeding, management, genetic and stress conditions) and post slaughter 
factors (postmortem glycolysis, postmortem shortening, conditioning, processing and 
cooking methods). Some of the above factors that affect meat tenderness are 
discussed below. There is a broad difference in tenderness which occurs between 
animals and muscles within the same animal. For example, the muscles from the 
round that are used in movement are higher in connective tissue content than muscles 
from the loin that are mainly used for structural support. The functions of the muscle 
within the animal are the primary reason for variation in tenderness of the muscles 
within the same animal. Smith et al. (1974) evaluated sensory attributes of chevon, 
pork, beef and lamb. It was reported that chevon had the same juiciness, but less 
tender and acceptable when compared to pork, beef and lamb at the same maturity 
and fatness. Wheeler et al. (2004) compared Bos taurus with Bos indicus. The latter 
species presents tougher meat, due to lower proteolysis of myofibrillar proteins, as a 
result of the greater activity of calcium-dependent protease inhibitor (Shackelford et 
al., 1991). Variation of meat tenderness within and among breeds of animals was 
attributed to genetic effect (Shackelford et al., 1994; Wheeler et al., 1996). 
 
As animal increased in chronological age, tenderness decreases (Purslow, 2005) and 
sensory panel scores for tenderness also decreases (Shackelford et al., 1995). Kannan 
et al. (2003) found longissimus muscle from young dairy goat to be tenderer than 
those from older dairy goats. However, Madruga et al. (2000) found similarities in 
sensory properties of complete and wether goats slaughtered at different maturity 
stage. Harper (1999) mentioned that the chief cause of toughness in meat of older 
animals is due to alteration in collagen properties. Collagen content in meat does not 
46 
 
alter much, but its solubility reduces as animal matures which influences meat 
tenderness. Several studies have shown that tenderness, measured by shear force, 
increases when better marbling is attained. The connective tissue rigidity is weakened 
with increased marbling accumulation resulting in tender meat (Berry, 1993; Killinger 
et al., 2004). A study carried out by Nishimura et al. (1999) seems to confirm this 
theory, since the development of intramuscular fat in the Longissimus dorsi muscle 
appears to disorganise the structure of connective tissue, leading to the tenderisation 
of highly marbled beef. In addition during cooking, distribution of fat throughout the 
muscle fibre forms a uniform shield that blocks some moisture loss, thus indirectly 
contributing to the juiciness (Cross, 1987; Bejerholm and Asalyng, 2004) and 
tenderness of meat.The effects of cooking on meat texture are quite complex and do 
not always result in tenderisation. Time, temperature and heating rate are the three 
variables which ultimately determine how cooking affects meat texture. Davey (1974) 
measured toughening of meat during isothermal heating. Compared to raw meat, 
o
isothermal heating at temperatures of 40 – 50 C produced a significant toughening of 
fibres which they attributed to myofibrillar protein denaturation. In the range of 50 – 
o o
65 C the fibres became tenderer during heating, but when heated at 65 – 75 C fibres 
were again observed to become tougher. The authors attributed the toughening at 65 – 
o
75 C to collagen shrinkage. This indicates that myofibrillar proteins denatures at 
temperatures lower than that of collagen (Martens et al., 1982). Christensen et al. 
o
(2011) reported no decrease of shear force with pork after heating 5hrs at 53 C 
isothermal. The shear force decreased only after cooking was extended for 17h and 
o
decreased even further when heating was at 58 C isothermal. This suggests that 
tenderisation is achieved at an extended cooking time. In addition, cooking method 
has an effect on meat tenderness. A muscle with high amounts of connective tissue 
47 
 
requires moist heat cooking method over a longer and slower cooking times to help 
break down connective tissue without losing moisture and make meat tender. For 
muscles with only few amounts of connective tissue, dry heat cooking method is 
recommended, this method transfer heat to meat without added moisture. In addition 
this method requires higher heat temperature and short cooking time (Bratzler, 1971). 
 
Meat juiciness is an essential factor when it comes to meat quality. Juiciness is 
described as the quantity of moisture squeezed out of a piece of meat by few gentle 
mastication (Ritchey and Hostetler, 1964). Sensory juiciness can be broken down into 
two parts: initial wetness and sustained juiciness. Initial juiciness is the wetness 
during the first few mastication generated by a quick release of meat juices, and 
sustained juiciness is caused by fat in the sample that causes a slow release of saliva 
after continued mastication (Bratzler, 1971). Previous work has shown the factors that 
have the highest influence on meat juiciness include: ultimate pH, fat content, cooking 
procedures and scale of doneness (Montgomery and Leheska, 2008). Initial liquid 
release from meat is absolutely impacted by level of doneness and procedure of 
cooking, whereas sustained juiciness is linked to intramuscular fat content (Pearson, 
1966). Procedures of cookery which result in the highest retention of meat liquid and 
lowest cooking losses are linked with improved juiciness of the final product (Smith, 
1972). Honikel (1998) described cook loss as a way of determining the water holding 
capacity of meat. Water holding capacity of meat is also influenced by meat pH. A 
low pH is highly damaging to meat water-binding if storage temperature is above 
o
20 C (Briskey and Kauffman, 1971). According to Aaslyng et al. (2003) cooking loss 
is based on raw meat quality, final temperature and cooking procedure. With higher 
degrees of doneness, there is more opportunity for cook loss and a reduction in 
48 
 
juiciness. During cooking denaturation of meat proteins causes structural changes to 
cell membranes of muscle fibres, along with shrinkage of muscle fibres and 
connective tissue (Honikel, 1998). During heating, water is lost as temperature 
increases. A rise in the scale of shrinkage during cooking is directly associated with 
loss of juiciness. Cooking losses due to rise in internal temperature are known to be 
inversely linked to juiciness (Ackerman et al., 1981). Beef cooked "rare" is juicier 
compared with beef cooked "well-done"; and pork, lamb, and veal, which are 
ordinarily cooked "well-done," are less juicy than beef (Weir, 1960).  
 
Marbling is a contributing factor to meat juiciness. When meat is heated, melted 
intramuscular fat becomes translocated along bands of perimysial connective tissues 
(Cross, 1987; Bejerholm and Asalyng, 2004). It has been discussed that, during 
cooking, distribution of fat throughout the muscle fibre forms a uniform shield that 
blocks some moisture loss, thus indirectly contributing to the juiciness of the meat 
(Cross, 1987; Bejerholm and Asalyng, 2004). Also Carpenter (1962) suggested that 
fats that surround muscle fibres helps to moisturize the fibres and so as to make it 
juicier. As marbling increases, palatability traits rated by consumers, such as flavour, 
juiciness and tenderness also increase (Smith et al., 1984; Parrish et al., 1991). 
Similarly, top loin steak with a moderate scale of marbling was juicier and more 
flavourful compared with modest, small and slight steak (Smith and Crouse, 1984; 
Lorenzen et al., 2003). Despite all the above explanation on eating quality of meat, 
acceptability of a meat product is dependent on the degree of preference, acceptance 
or liking of one product over another. 
 
 
49 
 
CHAPTER THREE 
3.0 Materials and Methods 
3.1 Experimental Design 
The experimental design used was a 3x3 factorial with three levels of the papain:(0, 
0.004g and 0.04gw/v) and 3 levels of the vinegar (0, 2.5% and 5%v/v) as the final 
concentration of the solution. 200g meat cubes from hindquarter of goat were added. 
The experimental design composed of nine treatments with three replications. 
Microbial testing for shelf life studies was conducted at three storage periods (1d, 15d 
and 30d) whiles sensory testing was conducted at two storage periods (1d and 15d). 
 
3.2 Sample Preparation 
The chevon was purchased from the Livestock and Poultry Research Centre, 
University of Ghana Legon and taken to the Cameron Meat Laboratory, University of 
Ghana, Legon. In all seven goats (three males and four females) between the ages of 2 
to 3years old and with average dressed weight of 6.5kg were used. The meat was 
o
processed and maintained at approximately 4 C. The hindquarter (approximately 
1300g) was deboned and all subcutaneous and intermuscular fat and visible 
connective tissues were removed. Meat was cut into 1.5cm x 1.5cm cubes and 
randomly assigned to nine treatments of marinade solutions in a ratio 1:1 (200g meat 
and 200ml mix). 
 
 
 
50 
 
3.2.1 Treatments 
Marinade treatments which consisted of 3 levels of papain and 3 levels of vinegar are 
shown in Table 2. 
Table 2: Treatments of chevon jerky with papain and vinegar at various 
concentration levels 
Treatments Papain (g) Vinegar (%) 
1 0 0 
2 0.004 0 
3 0.04 0 
4 0 2.5 
5 0.004 2.5 
6 0.04 2.5 
7 0 5 
8 0.004 5 
9 0.04 5 
 
 
3.2.2. Marination 
2
Chevon cubes (1.5cm ) were marinated in a closed zip-lock plastic bag (18cm x17cm) 
o
for about 12h at 4 C in a refrigerator; deionised water was used as control. The 
samples were removed from the marinade solution blotted with tissue paper to remove 
excess fluid. A spice-mix of (7.79% black pepper powder, 16.23% garlic powder, 
19.48% onion powder and 56.50% salt) was further sprinkled on the chevon at 1.54g 
per 200g meat and tumbled to ensure uniform spice distribution.  
 
3.2.3 Drying 
o
The oven (Elegance- Gaz, Tripoli – Lebanon) was preheated to approximately 65 C. 
 o
Samples were arranged on wire mesh over laid with aluminium foil and dried at 65 C 
for 10h. After drying, the chevon jerky samples were held in the oven for thirty 
minutes to cool. Samples were then placed in vacuum bags (18cm x 20cm), vacuum 
51 
 
o
packaged and stored at ambient temperature of between 29 to 30 C.  Samples were 
then randomly assigned to three storage time (1d, 15d and 30d) for shelf life studies. 
For the determination of drying rate (percent moisture content), the samples were 
weighed before drying. Samples were taken out from the oven and weighed every one 
hour during drying. The samples were dried for ten hrs. The loss in weight of the 
sample was calculated and hence its moisture content was obtained. 
 Drying rate (DR) =      Initial moisture content – final moisture content 
                                                         Final time – initial time          
 
3.3 Measurement 
3.3.1 pH Measurement 
The pH of the marinade solutions were measured before marinating the meat samples, 
using a pH meter (SND04819, Symphony, Singapore). The pH meter was first 
o
calibrated with standard buffer solutions of pH 4.0 and 7.0 at 25 C. The pH was 
measured by immersing the electrode in the marinade solution and recording the pH. 
Deionised water was used to clean the electrode after each testing and then blotted 
with tissue paper. 
 
3.3.2 Sensory Evaluation 
Sensory evaluation was conducted using six trained panelists (two post graduate 
students, three service personnel and one staff of the University). Their ages were 
between twenty two to forty years. The six panelists comprise of three males and 
three females. Three training sessions were organized. Panelists were also trained 
with representative samples as anchors for respective sensory attributes and 
screened based on their response on the attributes of the actual cooked meat 
52 
 
samples for various treatments during previous training session. Sensory 
evaluation was conducted on samples stored for 1d and 15d. This was due to 
massive mould growth on some of the samples from treatments containing papain 
only, after the 15 d of storage during the preliminary work. On the days of 
evaluation chevon jerky samples were presented in plastic containers marked with 
3-digit codes. Panelists cleansed their palates in between sample evaluation using 
water and apple juice. The tenderness (1 = extremely tough to 8 = extremely 
tender), juiciness (1= extremely dry to 8= extremely juicy), chewiness (1= 
extremely creamy to 8 = extremely rubbery), flavour  (1 = extremely strong to 8 = 
extremely bland) and acceptability = (1 extremely dislike to 8 = extremely like) of 
the samples were evaluated using 8 – point hedonic scale. Independent evaluation 
of samples was carried out by each panelist. 
 
3.3.3. Rehydration Ratio 
Rehydration of chevon samples was done according to the method of Doymaz and 
Smail (2011), the rehydration rate was carried out on sample with distilled water at 
ratio of 1:40 for 300min rehydration period under ambient condition. The sample was 
withdrawn from the distilled water every 30min and excess water was carefully 
removed by blotting with a tissue paper, before weighing. Weights of dried and 
rehydrated samples were measured using an electronic digital balance (Model: AAA 
250L, AE Adam, United Kingdom). The rehydration ratio (RR) was calculated by the 
following equation: 
 
Rehydration ratio =  Weight of sample after rehydration   
                               Weight of sample before rehydration 
53 
 
3.3.4 Microbiological Analysis 
Chevon jerky samples were aseptically removed from the vacuum packages after the 
respective days of storage (1d, 15d and 30d). Samples were weighed and further 
homogenised in sterilised phosphate buffer solution (ratio 1:2). An aliquot of samples 
extract (0.1ml) was pipetted into Eppendorf tube containing 0.9ml of phosphate buffer 
1 
solution (first dilution 101).  A 1:10 serial dilution was prepared from this stock (10 -
3
10 ).  
 
3.3.4.1 Total Plate Count 
Total aerobic count was carried out using plate count agar (Oxoid Ltd, England, 
Oxoid CMO 325). An aliquot (0.1ml) of each sample from previously prepared stock 
2 3   
of 10 and 10 diluents were pipetted onto sterile petri dishes and 15ml of melted and 
cooled plate count agar was added. Plates were gently swirled to uniformly mix the 
o
sample and incubated at 37 C for 48h. Colonies were counted from the plates 
expressed as colony forming unit (cfu) per gram of sample. 
 
3.3.4.2 Yeast and Mould 
Yeast and mould count was determined on potato dextrose agar medium (Titan 
Biotech Ltd, India, Oxoid CMO 139). An aliquot (0.1ml) of each sample from 
2 3   
previously prepared stock of 10 and 10 diluents were pipetted onto petri dishes and 
15ml of melted and cooled potato dextrose agar medium were added. Plates were 
o
gently swirled to uniformly mix the sample and incubated for 72 h at 25 C. Colonies 
were counted from the plates expressed as colony forming unit (cfu) per gram of 
sample. 
 
54 
 
3.3.4.3  E. coli 
E. coli count was carried out using eosin methylene blue agar (EMB) (Central Drug 
House (P) Ltd, India, DM 1317). An aliquot (0.1ml) of each sample from previously 
2 3   
prepared stock of 10 and 10 diluents were pipetted onto petri dishes and 15ml of 
melted and cooled EMB agar were added. Plates were gently swirled to uniformly 
o
mix the sample and incubated for 48h at 44 C. Colonies were counted from the plates 
expressed as colony forming unit (cfu) per gram of sample. 
 
3.3.4.4 Staphylococcus aureus 
Staphylococcus aureus count was determined using mannitol salt agar (MSA) (Merck 
Baird Parker, Germany, 1.07236). An aliquot of (0.1ml) of each sample from the 
2 3   
previously prepared stock of 10 and 10 diluents were pipetted onto petri dishes and 
15ml of melted and cooled MSA were added. Plates were gently swirled to uniformly 
o o
mix the sample and incubated for 24h at 35 C- 37 C. Colonies were counted from the 
plates expressed as colony forming unit (cfu) per gram of sample. 
 
3.4 Statistical Analysis 
Data for sensory evaluation were analysed using the frequency procedure of SAS 9.0. 
(Institute,Cary, NC). The chi-square test was used to test for significance of 
differences at p < 0.05. The microbiological data were log transformed and data 
analysed using mixed procedure of SAS 9.0 with marinade treatment and storage time 
as fixed effects. Means were separated using Proc mixed procedure. Comparisons of 
least square means were adjusted using the Bonferroni option. Means were considered 
significantly different at p < 0.05. Additionally, graph of drying and rehydration ratio 
data were drawn using Microsoft Excel. 
55 
 
CHAPTER FOUR 
4.0. Results 
4.1 Sensory Evaluation 
A trained panel of six was used to evaluate the sensory attributes of the treated jerky 
using 8 – point hedonic scale. The sensory evaluation data of chevon jerky indicated 
that vinegar and papain had an effect on tenderness and overall acceptability (p < 
0.05); however, it had no effect on juiciness, flavour and chewiness. Also there was 
no effect in all the sensory attributes among the treatments in terms of storage time on 
the chevon jerky except juiciness. The results of the attributes evaluated are shown in 
the tables below. 
 
4.1.1 Effect of Treatments on Chevon Jerky Tenderness 
The response of panelists to tenderness is as shown in Table 3. The distribution of 
tenderness scores was significantly different (p < 0.05) across treatments. Chevon 
jerky treated with  papain 0.04g (T3) had the highest score of 50%, however, it was  
ranked similarly with vinegar 2.5% (T4) and papain 0.04g +vinegar 5% (T9) as ―very 
tender to extremely tender‖.  
 
 
 
 
 
56 
 
Table 3: Frequency (%) of panelist’s response on tenderness scale of chevon 
jerky 
 Scale 
Extremely  Moderately  Slightly Very  
Treatment tough  tough  tender  tender  
to  to to  to  
very slightly  moderately  extremely  
tough tough tender tender 
T1 13.89 19.44 33.33 33.33 
T2 30.56 25.00 30.56 13.89 
T3 0.00 22.22 27.78 50.00 
T4 27.77 19.44 25.00 27.78 
T5 36.11 22.22 16.66 25.00 
T6 8.34 19.45 38.89 33.33 
T7 19.44 41.66 25.00 13.89 
T8 47.22 11.11 27.70 13.89 
T9 16.67 25.00 25.00 33.33 
2
 Chi-Square (x )=81.55, df= 56 
 
T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g, T4= Vinegar 2.5%, 
 T5= Papain 0.004g +vinegar 2.5%,T6= Papain 0.04g +vinegar 2.5%,  
T7= Vinegar 5%, T8=Papain 0.004g +vinegar 5%,  
T9=Papain 0.04g +vinegar 5%.   
 
Samples from control (T1) were ranked similarly as papain 0.04g (T3), vinegar 2.5% 
(T4),papain 0.04g +vinegar 5%  (T9) however, it was ranked between ―slightly tender 
to moderately tender‖ and ―very tender to extremely tender‖. Samples from papain 
0.004g +vinegar 2.5% (T5) and papain 0.004g +vinegar 5% (T8) were the least 
ranked and were ranked similarly as ―extremely tough to very tough‖. Based on the 
2
observed chi square (x ) value of 81.55, the null hypothesis is rejected at p > 0.05 and 
it was concluded that different marinades had different effects on the tenderness of the 
chevon jerky. 
 
57 
 
4.1.1.2 Effect of Storage Period on Chevon Jerky Tenderness  
The response of panelists to the effect of storage period on chevon jerky tenderness is 
presented in Table 4. 
 
Table 4: Frequency (%) of panelist’s response on the effect of storage period on 
tenderness of chevon jerky 
  Scale   
Storage Extremely Moderately Slightly Very 
Period  tough  tough   tender   tender  
(Day)  to  to  to  to  
very slightly  moderately extremely   
 tough tough tender tender 
1 24.07 20.37 28.4 27.16 
15 20.37 25.31 27.16 27.16 
2
Chi square (χ )=3.02, df = 7 
Tenderness scores for the various treatments were not significantly different (p > 
0.05) by the duration of storage. Samples analysed at 1d was ranked as ―slightly 
tender to moderately tender‖ whereas 15d was ranked between ―slightly tender to 
moderately tender‖. 
 
 
 
 
 
 
 
 
 
 
58 
 
4.1.2 Effect of Treatments on Chevon Jerky Chewiness 
The response of panelists to chewiness is as shown in Table 5. 
Table 5: Frequency (%) of panelist’s response on chewiness scale of chevon jerky 
  Scale   
Treatment Extremely Moderately Slightly  Very 
creamy creamy rubbery  rubbery 
 to   to to   to  
very  slightly  moderately extremely 
creamy creamy rubbery rubbery 
     
T1 11.11 27.77 44.45 16.67 
T2 11.11 22.22 47.23 19.44 
T3 11.11 30.55 41.67 16.67 
T4 8.34 13.89 50.00 27.78 
T5 19.44 27.78 30.56 22.23 
T6 11.11 13.89 44.44 30.55 
T7 5.56 22.22 50.00 22.22 
T8 13.89 13.89 36.11 36.11 
T9 8.33 25.00 50.00 16.67 
2
Chi-Square (χ ) =66.62, df= 56 
 
T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g, T4= Vinegar 2.5%, 
 T5=Papain 0.004g +vinegar 2.5%, T6= Papain 0.04g +vinegar 2.5%,  
T7=Vinegar 5%, T8=Papain 0.004g +vinegar 5%,  
T9=Papain 0.04g +vinegar 5%.   
 
In connection with chewiness, the scores were the same (p > 0.05) across treatments. 
The control and the test treatments were all ranked by panelists as ―slightly rubbery to 
moderately rubbery‖ with the exception of papain 0.004g +vinegar 2.5% (T5) which 
was ranked between ―slightly rubbery to moderately rubbery‖ and ―very rubbery to 
extremely rubbery‖.  
 
 
 
 
59 
 
4.1.2.1 Effect of Storage Period on Chevon Jerky Chewiness 
Table 6 shows no effect of storage period on chevon jerky chewiness. 
 
Table 6: Frequency (%) of panelist’s response on the effect of storage period on 
chewiness of chevon jerky 
  Scale   
Storage Extremely Moderately Slightly Very  
Period creamy  creamy  rubbery  rubbery  
(Day) to  to  to to extremely 
very slightly moderately  rubbery 
 creamy creamy rubbery 
1   11.11 2 0.99  38.27 2 9.63 
15 11.11 22.84 49.38 16.67 
2
Chi square (χ )=13.08, df= 7 
 
The distribution of chewiness scores was the same across storage period. Samples 
evaluated at 1d and 15d were similarly ranked as ―slightly rubbery to moderately 
rubbery‖. 
 
 
 
 
 
 
 
 
 
60 
 
4.1.3 Effect of Treatments on Chevon Jerky Juiciness 
The response of panelists to juiciness is as shown in Table 7. The distribution of 
juiciness scores was not significantly different (p > 0.05) across treatments. 
 
Table 7: Frequency (%) of panelist’s response on juiciness scale of chevon jerky 
           Scale   
Treatment Extremely Moderately Slightly  Very  
dry  dry  juicy  juicy  
to  to  to  to 
very  slightly  moderately  extremely  
dry dry juicy juicy 
T1 25.00 8.34 44.44 22.22 
T2 27.78 36.11 22.22 13.89 
T3 13.89 27.78 44.44 13.89 
T4 19.45 27.78 27.77 25.00 
T5 19.45 16.67 36.11 27.78 
T6 30.55 16.67 36.11 16.67 
T7 25.00 19.44 27.77 27.78 
T8 33.33 19.45 36.11 11.11 
T9 22.23 19.45 36.11 22.22 
2
Chi-Square (χ )=71.44, df = 56 
 
T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g, T4= Vinegar 2.5%, 
 T5= Papain 0.004g +vinegar 2.5%, T6= Papain 0.04g +vinegar 2.5%,  
T7=Vinegar 5%, T8=Papain 0.004g +vinegar 5%,  
T9=Papain 0.04g +vinegar 5%.   
 
Samples from papain 0.04g (T3) and the control (T1) obtained the highest percent 
score and were similarly ranked as ―slightly juicy to moderately juicy‖. All the other 
treatments with the exception of papain 0.004g (T2), vinegar 5% (T7) and vinegar 
2.5% (T4) were also similarly ranked as ―slightly juicy to moderately juicy‖ as the 
61 
 
above however, they obtained a lower percentage. Samples from papain 0.004g (T2) 
and vinegar 2.5% (T4) were the least ranked as ―moderately dry to slightly dry‖. 
 
4.1.3.1 Effect of Storage Period on Chevon Jerky Juiciness 
The response of panalists to the effect of storage period on chevon jerky juiciness is 
presented in Table 8. 
 
Table 8: Frequency (%) of panelist’s response on the effect of storage period on 
juiciness of chevon jerky 
 Scale 
Storage Extremely  Moderately  Slightly  Very  
dry  dry  juicy  juicy  
Period to  to  to  to  
very  slightly  moderately juicy extremely juicy 
(Day) dry dry 
1 24.69 24.08 35.19 16.05 
15 23.46 18.52 33.95 24.08 
2
Chi square (x ) =15.44, df= 7 
 
 Juiciness scores for the various treatments were significantly different (p < 0.05) by 
the duration of storage. Samples evaluated at 1d were ranked as ―extremely dry to 
very dry‖ (24.69%) but were ranked as ―very juicy to extremely juicy‖ (24.08%) at 
15d. 
 
 
 
62 
 
4.1.4 Effect of Treatments on Chevon Jerky Flavour 
Table 9 shows the response of panalists to chevon jerky flavour. 
 
Table 9: Frequency (%) of panelist’s response on flavour scale of chevon jerky 
  Scale   
Treatment Extremely  Moderately  Slightly  Very  
bland  bland  strong  strong  
 to  to  to  to  
very  slightly  moderately  extremely  
bland bland strong strong 
T1 13.89 19.44 44.44 22.33 
T2 5.56 22.22 63.89 8.34 
T3 16.67 41.67 33.33 8.33 
T4 2.78 13.89 55.56 27.78 
T5 11.11 11.12 55.56 22.22 
T6 8.33 22.22 44.45 25.00 
T7 8.33 16.67 30.55 44.44 
T8 11.11 30.55 38.89 19.45 
T9 5.56 27.77 41.67 25.00 
2
Chi-Square(x ) =60.54, df= 56 
T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g, T4= Vinegar 2.5%, 
 T5= Papain 0.004g +vinegar 2.5%, T6= Papain 0.04g +vinegar 2.5%,  
T7=Vinegar 5%, T8=Papain 0.004g +vinegar 5%, T9=Papain 0.04g +vinegar 5%.   
 
The distribution of flavour scores was the same (p > 0.05) across treatments. The 
results for flavour analyses indicated that with the exception of papain 0.04g (T3) and 
vinegar 5% (T7), all the other treatments were similarly ranked by panelists as 
―slightly strong to moderately strong‖. Papain 0.04g (T3) and vinegar 5% (T7) were 
ranked as ―moderately bland to slightly bland‖ and ―very strong to extremely strong‖ 
respectively. 
 
63 
 
4.1.4.1 Effect of Storage Period on Chevon Jerky Flavour 
Table 10 shows the response of panelists to the effect of storage period on chevon 
jerky flavour. 
 
Table 10: Frequency (%) of panelist’s response on the effect of storage period on 
flavour of chevon jerky 
 Scale 
Storage Extremely bland  Moderately Slightly  Very  
Period to  bland  strong  strong  
(Day) very  to  to  to  
bland slightly moderately extremely 
 bland strong strong 
0 8.02 21.6 44.44 25.93 
2 10.49 24.07 46.29 19.14 
2
Chi square (x ) = 7.29, df= 7 
 
The flavour scores for the various treatments were not significantly different (p > 
0.05) by the duration of storage. Samples evaluated at 1d and 15d were similarly 
ranked as ―slightly strong to moderately strong‖ (Table 10). 
 
 
 
 
 
 
 
 
 
64 
 
4.1.5 Effect of Treatment on Chevon Jerky Acceptability 
The response of panelists to chevon jerky acceptability is as shown in Table 11.  
 
Table 11: Frequency (%) of panelist’s response on acceptability scale of chevon 
jerky 
  Scale   
Treatment Extremely Moderately Slightly  Very  
dislike  dislike  like  like  
to very  to  to  to  
dislike slightly  moderately extremely 
dislike like  like 
     
T1 5.56 19.45 22.22 52.78 
T2 2.78 5.56 50.00 41.67 
T3 13.89 13.89 52.78 19.45 
T4 11.11 30.56 41.67 16.67 
T5 8.34 19.44 38.88 33.33 
T6 16.67 13.89 55.56 13.89 
T7 11.11 33.33 47.22 8.33 
T8 5.56 16.67 38.89 38.89 
T9 16.67 8.34 58.33 16.67 
2
Chi-Square (x ) =84.14, df= 56 
T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g, T4= Vinegar 2.5%, 
 T5= Papain 0.004g +vinegar 2.5%,T6= Papain 0.04g +vinegar 2.5%,  
T7=Vinegar 5%, T8=Papain 0.004g +vinegar 5%, T9=Papain 0.04g +vinegar 5%. 
 
The distribution of acceptability scores was significantly different (p < 0.05) across 
treatments. Panelists scored all the treatments as ―slightly like to moderately like‖ 
with the exception of papain 0.004g + vinegar 5% (T8),which was ranked  between 
―slightly like to moderately like‖ and ―very like to extremely like‖ as well as control 
(T1) which was also scored as ―very like to extremely like‖. 
65 
 
4.1.5.1 Effect of Storage Period on Chevon Jerky Acceptability 
Table 12 shows the response of panelists to the effect of storage period on chevon 
jerky acceptability. 
 
Table 12: Frequency (%) of panelist’s response on the effect of storage period on 
acceptability of chevon jerky 
  Scale   
Storage  Extremely  Moderately  Slightly  Very  
Period dislike  dislike  like  like  
(Day) to  to  to  to  
very  slightly  moderately extremely 
dislike dislike  like  like 
1 10.49 19.76 43.21 26.54 
15 9.88 16.05 46.92 27.16 
2 
Chi-Square(x ) =5.49, df= 7 
 
The distribution of acceptability scores was the same (p > 0.05) across storage period. 
Samples evaluated in 1d and 15d were similarly rated as ―slightly like to moderately 
like‖. 
 
 
 
 
 
 
 
66 
 
4.2 Microbiological Evaluation 
Microbial flora analyses were carried out at 1d, 15d and 30d of storage, vacuum 
packaged chevon jerky samples from each treatment were aseptically removed and 
analysed. Total plate count, Staphylococcus aureus, E. coli, yeast and mould were 
evaluated. Results from the various microbiological analysis of the vacuum packaged 
chevon jerky stored within30d period are presented in Table 13 and 14. 
 
Table 13: Effect of treatments on microbial count (log CFU/g meat sample) of 
vacuum packaged chevon jerky stored for 30d 
Treatment TPC SEM E.coli SEM S. SEM Yeast SEM 
aureus and 
mould 
1 1.00 0.43 0.31 0.28 0.74 0.46 0.59 0.43 
2 1.18 0.43 0.00 0.28 0.95 0.46 0.68 0.43 
3 1.27 0.43 0.31 0.28 0.74 0.46 1.12 0.43 
4 1.22 0.43 0.92 0.28 1.06 0.46 0.87 0.43 
5 1.46 0.43 0.64 0.28 1.04 0.46 0.90 0.43 
6 1.60 0.43 0.00 0.28 1.14 0.46 0.98 0.43 
7 0.87 0.43 0.00 0.28 0.71 0.46 0.96 0.43 
8 1.59 0.43 0.72 0.28 0.99 0.46 0.59 0.43 
9 1.76 0.43 0.00 0.28 0.38 0.46 0.56 0.43 
No significant difference was found among treatments (p > 0.05) 
Treatments:T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g,  
T4= Vinegar 2.5%,T5=Papain 0.004g +vinegar 2.5% T6= Papain 0.04g +vinegar 
2.5%, T7=Vinegar 5%,  T8=Papain 0.004g +vinegar 5%,  
T9=Papain 0.04g +vinegar 5%., TPC= Total plate count, SEM= standard error mean 
 
 
67 
 
Table 14: Effect of storage time on microbial count (log CFU/g meat sample) of 
vacuum packaged chevon jerky stored for 30d 
Storage TPC SEM E.coli SEM S. aureus SEM Yeast SEM 
Period and 
(Day) mould 
a a a a
1 0.46  0.25 0.68  0.16 1.96  0.26 0.95  0.25 
b C b a
15 1.59  0.25 0.19  0.16 0.62  0.26 1.17  0.25 
c b c a
30 1.93  0.25 0.09  0.16 0.00  0.26 0.30  0.25 
Figures with different superscript in a column are significantly different p < 0.05 
SEM= standard error mean, TPC= Total plate count 
 
4.2.1 Effect of Treatment on Total Plate Count 
The results for total plate counts for vacuum packaged chevon jerky stored for 30d are 
provided in Table 13 and 14. There was no significant difference (p > 0.05) in total 
plate count among treatments (table 13). Thus, treatments had no effect on total plate 
count.  The highest total plate count was observed in samples from papain 0.004g 
+vinegar 5% (T8) whereas the lowest count was observed in vinegar 5% 
(T7).Samples from control (T1) recorded the second lowest in total plate count. 
 
4.2.1.1 Effect of Storage Period on Total Plate Count 
The result for the effect of storage period on total count is as shown in table 14. 
Significant differences (p < 0.05) in total plate count during storage were observed. 
As storage period increased from 15d to 30d total plate count increased from1.59 to 
1.93log cfu/g.  
 
68 
 
4.2.2 Effect of Treatment on E.coli 
The results for E.coli counts for vacuum packaged chevon jerky stored for 30d are 
shown in Table 13. There was no significant difference (p > 0.05) in E.coli count 
among treatments. Thus, treatments had no effect on E.coli. Samples from vinegar 
2.5% (T4) recorded the highest E.coli counts whereas papain 0.04g (T3) recorded the 
same microbial count as that of the control (T1), however, samples from papain 
0.004g (T2), papain 0.04g +vinegar 2.5% (T6), vinegar 5% (T7),  and papain 0.04g 
+vinegar 5% (T9) all recorded 0.00log cfu/g in E.coli.  
 
4.2.2.1 Effect of Storage Period on E.coli 
The results indicated a significant difference in storage time (p < 0.05) as shown in 
table 14. As storage period progressed from 15d to 30d there was a declined in E.coli 
count from 0.19 to 0.09log cfu/g. However, no significant difference was observed at 
15d and 30d. 
 
4.2.3 Effect of Treatment on Staphylococcus aureus 
S. aureus counts for vacuum packaged chevon jerky stored for 30d are presented in 
table 13. There was no significant difference in S. aureus counts among treatments (p 
> 0.05). The highest S. aureus count was observed in papain 0.04g +vinegar 2.5% 
(T6) whereas the lowest S. aureus count was recorded in samples from papain 0.04g 
+vinegar 5% (T9). Samples from control (T1) and papain 0.04g (T3) recorded similar 
S. aureus count. 
 
69 
 
4.2.3.1 Effect of Storage Period on Staphylococcus aureus 
The results for S. aureus counts indicated a significant difference (p < 0.05) in storage 
period (table 14). As storage period increased from 1d to 30d, there was a decreased 
in S. aureus count, S. aureus count decreased from 1.96 to 0.00log cfu/g.  
 
4.2.4 Effect of Treatment on Yeast and mould 
Results for yeast and mould counts for vacuum packaged chevon jerky stored for 
30days are presented in table 13. As presented in table 13 no significant difference (p 
> 0.05) was observed in yeast and mould counts among treatments. The highest yeast 
and mould count was recorded in papain 0.04g (T3) whereas the lowest was observed 
in papain 0.04g +vinegar 5% (T9). Control (T1) and papain 0.004g +vinegar 5% (T8) 
recorded a similar yeast and mould count. 
 
4.2.4.1 Effect of Storage Period on Yeast and mould 
There was a significant difference in storage time in yeast and mould counts (p < 
0.05) as shown in table 14. As storage period progressed from 15d to 30d, there was a 
declined in yeast and mould count from 1.17 to 0.30log cfu/g. 
 
 
 
 
 
 
70 
 
4.3 Moisture content (%) 
Figure 1 shows the effect of papain and vinegar on chevon jerky moisture content (%) 
o
during drying. The samples were dried at approximately 65 C for 10h.  
 
100 Drying curve
90
80
T1
70
T2
60
T3
50
T4
40
T5
30
T6
20
T7
10
T8
0
0 60 120 180 240 300 360 420 480 540 600 T9
Time (min)
 
Figure 1: The effect of papain and vinegar on moisture content of chevon jerky 
during drying 
Treatments: T1= Control, T2=Papain 0.002%,   T3= Papain 0.04g,  
T4= Vinegar 2.5%, T5= Papain 0.004g +vinegar 2.5%, 
T6= Papain 0.04g +vinegar 2.5%, T7= Vinegar 5%,  
T8=Papain 0.004g +vinegar 5%, T9=Papain 0.04g +vinegar 5%.  
 
As drying time progressed from time 0 to 60min there was rapid decreased in 
moisture content among all treatments. Moisture content decreased continuously at a 
decreasing rate with increased in drying time from 60min to 360min, however at 
420min to 600min there was no difference in moisture content reduction among 
treatments. At the end of the drying period all the test samples recorded lower 
moisture content than that of the control (T1).  Samples from vinegar 2.5% recorded 
71 
 
Moisture content %
the least (1.71%) moisture content whereas the highest (3.61%) was observed in 
control (T1) samples. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
72 
 
4.4 Rehydration Characteristics 
Sample from each treatment was soaked in water and their weights recorded after 
every 30min for 300min. Results of the effect of the respective treatments on 
rehydration rate of the chevon jerky are presented in Figure 2. 
Figure 2 shows the rehydration curve of the various treatments. All the treatments 
increased in percent moisture content as rehydration time increased from 0 -300min. 
Rehydration of chevon jerky
25
T1
20 T2
15 T3
T4
10
T5
5
T6
0 T7
0 30 60 90 120 150 180 210 240 270 300 T8
Time (min) T9
 
Figure 2: Effect of treatments on rehydration on percent moisture content 
(%MC) of chevon jerky 
Treatments: T1= Control, T2=Papain 0.004g,   T3= Papain 0.04g, T4= Vinegar 
2.5%,T5= Papain 0.004g +vinegar 2.5%, T6= Papain 0.04g +vinegar 2.5%, T7= 
Vinegar 5%, T8=Papain 0.004g +vinegar 5%, T9=Papain 0.04g +vinegar 5%, % MC 
= Percent moisture content. 
 
As rehydration time progressed from time 0 to 300min there was an increase in 
weight among all treatment samples. Samples from papain 0.004g (T2) and papain 
0.04g (T3) were the same with samples from control (T1). Similarly, all treatment 
combination samples from papain 0.004g + vinegar 2.5% (T5), papain 0.04g +vinegar 
2.5% (T6), papain 0.004g +vinegar 5% (T8) and papain 0.04g +vinegar 5% (T9) were 
the same from the beginning of rehydration to the end. Samples from control (T1) 
73 
 
Rehydration  on %MC
recorded the least %MC of 9.83 whereas samples from vinegar 2.5% (T4) recorded 
the highest %MC (19.94) after rehydration.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
74 
 
CHAPTER FIVE 
5.0 Discussion 
5.1 Sensory Evaluations 
Dried meat products, in general are associated with toughness due to the low moisture 
content. Marinades are sauces that are designed to flavour and tenderise meat and 
marination is commonly used to improve functional and sensory properties of meat 
(Latif, 2011). Results from table 3 shows that papain at higher concentration 0.04g 
(T3) made the meat more tender as compared to lower concentration 0.004g (T2). 
Several authors have reported of papain‘s ability to breakdown connective tissue and 
myofibrillar proteins and sometimes resulting in deterioration of sensory attributes of 
meat (Dransfield and Etherington, 1981; Miller et al., 1989; Iizuka and Ashima, 
1999).  Doneva (2015) reported that higher concentration of papain resulted in a 
complete hydrolysis of meat proteins, deteriorating the appearance and taste of the 
meat. Also Ashie et al. (2002) found a decrease in toughness of beef briskets and top 
rounds injected with papain whereas an increased in the dosage resulted in 
deterioration of sensory qualities. However, in this study the concentration of papain 
used did not cause any deterioration of sensory characteristics. Lower concentration 
of vinegar 2.5% (T4) also had effect on meat tenderness and made the meat more 
tender compared to higher concentration of vinegar 5% (T7), according to Stanston 
and light (1989) and Berge et al. (2001) acidic treatment of meat speedup the 
activation of cathepsin and improved collagen breakdown to gelatin at low pH during 
thermal treatment, however, it could be that 5% vinegar (T5) extensively denatured 
proteins which diminished protein quality properties and reduced water holding 
capacity. Pearson and Young (1989) has stated that water lost due to unrepairable loss 
of protein quality properties includes free, immobilised, and bound water, leading to 
75 
 
lost of tenderness. On the contrary, Wijayawardana et al. (2001) reported that an 
increase in marinating time decreased shear force value of meat treated with vinegar. 
However, the type of muscle (Longissimum dorsi muscle) used could have 
contributed to the reduction in shear force value. In contrast to this study Hinkle 
(2010) found no significant change (p > 0.05) in tenderness of beef bottom round 
treated with acetic acid, lactic acid and sodium citrate dehydrate at low concentration 
but significant difference was observed at high concentration. The result from this 
study was different because Hinkle (2010) injected the acids into the meat and cured 
the meat for 2 wk whereas in the case of this study the meat were immersed in the 
marinade and marinated for 12h.  
 
With regard to chewiness, dried meat is associated with toughness and jerky is no 
exception due to its exceptional low moisture content to inhibit microbial growth. The 
lack of effect of treatments on chewiness of the chevon jerky could be due to loss of 
moisture during drying, in agreement with this study Pietrasik and Shand (2008) 
compared moist and dry cooking and found reduced shear force value in moist 
cooking than dry cooked method with Aspergillus oryzae injected roasts.  
 
On the other hand, the lack of effect of treatments on juiciness of the chevon jerky 
was unexpected since significant difference were observed in the tenderness of the 
samples and juiciness is directly correlated to the tenderness of meat. The inability of 
the treatments to have effect on juiciness may be due to low water holding capacity 
and loss of moisture during drying. This result is in agreement with Gerelt et al. 
(2000) who observed lower values in juiciness of meat treated with papain for a 
longer duration of time. Ashie et al. (2002) also reported of papain activity during 
76 
 
refrigerator storage. Subsequent to the drying of the meat, papain treated samples 
were softer, slimy and slippery to touch compared to the other treatments, this 
indicates that papain caused excessive degradation of myofibrillar protein structure at 
the time of marinating as well as during cooking resulting in excessive loss of 
moisture. Also most of the marinades had lower pH values which can negatively 
affect the juiciness of the meat; Goli et al. (2007) reported that pH value of meat 
products is greatly essential because it has a major impact on water holding capacity 
(WHC), tenderness and juiciness. As the pH of meat diminishes nearer to the 
isoelectric point (pH 5.2), it follows with a reduction in the capacity of the 
microstructure to immobilise and bind moisture (Hamm, 1975). The low pH of the 
marinades probably caused excessive denaturing of the myofibrillar proteins and 
resulted in loss of meat juice before and during cooking. 
 
The sensory results indicated that the treatments did not have any effect on chevon 
jerky flavour; this is probably due to the marinade concentration of the test treatments 
which were satisfactory. The result partly agrees with Djeri (2007) who found no 
significant differences (P > 0.05) in flavour of treated chevon ribs with apple cidar 
vinegar at 1d; however as storage days progress there was a significant difference in 
flavour among treatments. This may suggests that the effects of treatments on chevon 
jerky flavour could have been more pronounced if the storage time increased beyond 
the 15d. The rating of samples from control (T1) as ―slightly strong to moderately 
strong‖ with the other treatments containing vinegar may be due to a halo effect or a 
carryover effect from tasting the other treatments which contains vinegar.  
 
77 
 
According to Ashie et al. (2002) and Doneva et al. (2015) higher concentration of 
papain resulted in deterioration of organoleptic qualities of meat and produce 
undesirable flavours. Papain is also associated with a bitter or pungent odour, 
however, in this study it was rated as moderately bland to slightly bland which may be 
due to the fact that the papain did not cause excessive hydrolysis of the meat proteins 
to result in a mushy texture associated with those undesirable flavours at the 
concentration tested. 
 
The treatments had an effect on overall acceptability of the chevon jerky and since the 
major essential sensory qualities of jerky are texture, colour and flavour, which are 
depended on the raw ingredients and several technological factors (Albright et al., 
2000), it can be suggested that tenderness contributed to the acceptability of the 
chevon jerky, since only papain 0.004g +vinegar 5% (T8) and papain 0.004g +vinegar 
2.5% (T5) out of the nine treatments were scored as extremely tough to very tough. 
Lack of effect of treatments on flavour of the chevon jerky may have also accounted 
for the acceptability of the chevon jerky; however, Maughan et al., (2012) has shown 
that sourness is negatively connected to liking. In this study the presence of the acidic 
taste associated with vinegar did not cause dislike to any of the treatments. Overall 
samples from control (T1) had the highest acceptability score and was ranked as ―very 
like to extremely like‖ which may be due to its high rating in tenderness. 
 
 
 
78 
 
5.2 Microbiological Evaluation 
The processing of jerky varies from the processing of other snack products because 
thermal treatment is used to achieve the desired sensory quality and stored safely at 
ambient temperature.  Jerky is dried to a low water activity in order to prevent 
microbial development and prolong shelf life. However, outbreak of food borne 
diseases has been connected to the consumption of jerky (CDC, 1995; Eidson et al., 
2000). The degree and duration of the survival of pathogens on jerky during storage 
may differ based on the type of bacteria and the varied antimicrobial hurdles that is 
employed (Torres et al., 1994; Quintion et al., 1997: Shimokomaki et al., 1998). To 
attain stability, jerky must have moisture protein ratio (MPR) 0.75:1.0 and water 
activity (aw) <0.8 (USDA - FSIS, 2004). The water activity is defined as the free 
water accessible to microorganisms for their development. Hence, water activity is 
essentially for accessing the degree of microbial development in meat products and 
the effect on products characteristics during storage (Choi et al., 2007). Microbial 
contamination of meat can be categorized as aerobic or anaerobic, based on the 
environments in which it thrives and the type of microbes involved. The quantity of 
microorganisms contained in a product will dictate the rate of product quality spoilage 
or effect of disease cause to humans (Fleet, 1999).  
 
In this study the treatment did not have effect on any of the targeted microbes. 
However, extending storage period led to a reduction in the total number of microbes 
present at the end of the shelf life studies. This may be ascribed to the inhibition of 
aerobic microbial development by the vacuum packaged material, since vacuum 
packaging objective is to protect meat products from contact with oxygen from the air 
which aids the growth of aerobic microorganisms (Jeremiah, 2001). Microorganisms 
79 
 
such as Staphylococcus aureus (Surimi and Surimi, 2013), E.coli (Singleton, 1999) 
and yeast (Carlile et al., 2001) are facultative anaerobes. Drying is known to decrease 
the water content of meat product which most importantly lowers the water activity to 
a degree where microorganism are no longer able to obtain adequate amount of water 
for their growth (Santchurn et al., 2012). 
 
The microbial count recorded for the entire microbiological analysis (total plate count, 
E. coli, S. aureus, yeast and mould) at the various sampling time 1d, 15d and after the 
30d of the shelf life studies was in a range of 0.00-1.96log cfu/g. The low microbial 
levels seem to be due to the fact that microbial growth was inhibited at low water 
activity. Faith et al. (1998) reported that viability of bacteria in jerky was decreased as 
the drying temperature and time were extended. Also, Jung et al. (1994) observed 
moisture content and water activity of jerky decreased during storage. Moisture 
content and water activity are closely related (Leistner, 1987). Choi et al. (2008) also 
observed a reduction in water activity of hot air-drying jerky in plastic pack as the 
storage period prolonged. In this study the length of drying time which was 10h, may 
have contributed to the reduction in microbial numbers in all the treatments through 
reduction of moisture content in meat. In the case of total plate count there was an 
increase with increased storage period, however, the total plate count remained well 
below the spoilage limit of 7.0log cfu/g (Egan et al., 1980). S. aureus and E. coli, 
counts were high at the initial sampling 1d, however they were reduced at 15d and 
30d as storage period progressed which may be due to unfavourable hurdles 
conditions such as low moisture and water activity. The prevention of S. aureus grow 
that water activity of 0.91 in anaerobic conditions has already been reported by 
Leistner et al. (1981). This indicates the synergistic effect of low water activity and 
80 
 
vacuum packaging on the development of S. aureus in this study. S. aureus counts 
required to produce detrimental effects has been reported to be 7logcfu/g (Troller, 
1976). However, S. aureus in this experiment was zero at the end of the shelf life of 
studies 30d.Yeast and mould count was low at the initial sampling 1day; however, it 
increased in count at 15d. Yeast and mould have the capacity to thrive in acidic 
medium and at low water activity (Corry, 1978; Jay, 1987); this might have allowed 
them to grow to some degree at 15dhowever, unfavourable hurdles conditions may 
have led to a reduction in yeast and mould count at 30d. Ingham et al. (2006) reported 
that although toxin-producing moulds can develop on some intermediate meat 
products, however, commercial jerky producers use vacuum bags to arrest their 
development. Moulds are aerobic microorganisms that require oxygen for their 
growth, whereas in vacuum packaged bacteria that can thrive and cause deterioration 
to product quality are facultative anaerobic and anaerobic (Ray and Bhunia, 2013). 
Also Leistner (1987) reported that deterioration of several ready to eat meat products 
by mould could be prevented when the product pH is decreased, however, in this 
study vinegar which was part of the treatments with a low pH of approximately 3, did 
not have effect on yeast and mould count of the chevon jerky. Gourama and 
Bullerman (1995) has also reported that lactic acid and acetic acid with pH 3.35 and 
3.81 respectively, displayed little efficacy in controlling fungi growth.  
 
 
 
 
81 
 
5.3 Moisture Content (%) (Drying curve) 
A major property that defines the good characteristics of meat is its capacity to 
maintain water found in the meat and water included. Moisture in meat is essential for 
palatability but is also a medium for microbial growth. Drying meats into jerky will 
typically eliminate any concerns with moisture. One of the major essential 
characteristic of dry meat products is moisture content (Yang et al., 2009). Whole 
muscle jerky is said to be either too dehydrated or tough (Miller et al., 1996) and 
some minced or restructured jerky products are tender, however, they contain great 
amount of fat as well as water activity, leading to the promotion of rancidity and 
microorganism growth (Quinton et al., 1997). USDA - FSIS (2004) suggest that jerky 
must have a moisture-to-protein ratio of less than or equal to 0.75:1 and a water 
activity (aw) less or equal to 0.85.Lowering water activity by decreasing moisture 
content will generate tougher meat products, but the inclusion of papain and vinegar 
will help in controlling the water activity as well as texture. 
 
Figure 1 shows the influence of papain and vinegar on the moisture content of chevon 
jerky during drying. The figure shows that there is a correlation between moisture 
content and drying time. Moisture content decreases continuously with increase in 
drying time for all treatments. The rate of moisture content reduction was rapid from 
time 0 to 60min among all treatments probably due to evaporation of surface water. 
As drying time progressed from 60min to 360min the rate of moisture content 
decreased was low. As drying time progressed from 0 to 600min, samples from higher 
concentration of papain 0.04g (T3) recorded a higher decreased in moisture content 
from 81.72 to 2.93% compared to lower concentration of papain 0.004g (T2) (80.64 
to 3.33%). Rawdkuen et al. (2011) found that higher dosage of enzyme caused a 
82 
 
reduction in meat moisture content. Similarly, Ionescu et al. (2008) reported that 
higher concentration of papain resulted in higher cooking loss during thermal 
treatment. Istrati (2008) also found that higher break down of myofribillar proteins by 
papain caused a decrease in the capacity of the meat to hold water.  In this study the 
proteolytic enzymes probably may have caused the low moisture content recorded in 
high concentration of papain 0.04g (T3) possibly due to the degradation of the 
myofibrillar and collagen protein which created more avenues for moisture to escape 
during the drying process. Samples from lower concentration of vinegar 2.5% (T4) 
recorded a higher initial moisture content of 89.02% compared with that of higher 
concentration of vinegar 5% (T7) 86.06%. Moisture content decreased continuously 
between the above treatments with increased in drying period from 0 to 600min. 
However, moisture content reduction was high in samples from vinegar 2.5% (T4) 
compared to vinegar 5% (T7). At the end of the drying period samples from lower 
concentration of vinegar 2.5% (T4) recorded a lower moisture content of 1.71% 
compared with higher concentration of vinegar 5% (T7)  (2.45%). Meat pH value is 
very essential because it has influence on water holding capacity (Goli et al., 2007). 
Also Hammand Deatherage (1960) reported that raw meat water-holding capacity 
rises quickly as pH reduces below muscle electrically neutral point of 5.1, which 
increases correlatively to the number of positive charged protein groups. In addition, 
at a higher pH value of 6.0 or less than 4 the quantity of theses reactive groups 
accessible to bind water is greatly increased (Gault, 1985). Additionally, Rao and 
Gault (1989) stated that lowering the pH of meat below its electrically neutral point 
favoured the expansion and moisture absorption by stromal proteins; collagen, elastin 
and reticulin whereas lowering the meat pH further to pH 4.0 and below, will result in 
the expansion and absorption of added water by the myofibrillar proteins. This 
83 
 
probably contributed to the high moisture content observed in vinegar 5% (T7), since 
it was able to retained more moisture during cooking compared with vinegar 2.5% 
(T4). Samples from treatment combination papain 0.004g+ vinegar 5% (T8) also 
recorded higher initial moisture content of 86.10%. There was a rapid decreased in 
moisture content from 0 to 60min. There was continuous decreased in moisture 
content as drying time progressed from 420 to 600min. At the end of the drying 
period the above sample recorded the second lowest moisture content of 1.83%. This 
shows the synergistic effect between lower concentration of papain 0.004g and higher 
concentration of vinegar 5% in moisture content reduction. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
84 
 
5.4 Rehydration Rate 
According to An et al. (2012) the purpose of rehydration processes is to reinstate the 
standard properties of a fresh material when the dehydrated material is submerged in 
an aqueous solution. Lewicki (1998) reported that rehydration properties of 
dehydrated food substance are employed as a standard to check whether 
physicochemical alterations happened during the dehydrated process due to 
processing methods, pre- treatments and product constituents. 
 
Figure 2 shows the effect of treatments on percent moisture content rehydration of 
chevon jerky.  As rehydration time increased from 0 to 300min there was an increased 
in percent moisture content among all the treatments, however, percent moisture 
content increased at a gradual pace as rehydration time progressed. Rate of 
rehydration was high at the early stage (from 0 to 30min), among all the treatments, 
probably due to surface and capillary suction. Deng et al. (2014) also obtained the 
same result as above. Jayaraman et al. (1990) observed unrepairable biological cell 
fracture and separation, which resulted in reduction in firmness and subsequently, a 
heavy frame break down, massive shrunk capillaries with low affinity for water, as 
seen by the incapability for sufficient amount of water to permeate and completely 
rehydrate. In this study, the low % MC rehydration and the similarity between 
samples from papain 0.004g (T2), papain 0.04g (T3) and control (T1) was probably 
due to excessively shrunken cellular structure due to loss of moisture during drying 
which led to low rate of rehydration. Samples from lower concentration of vinegar 
2.5% (T4) recorded higher %MC rehydration probably due to less degradation of 
muscle protein and little or no shrunk cellular structure during drying which led to 
higher water uptake during rehydration. Shiby et al. (2015) observed an increased in 
85 
 
rehydration ratio in freeze dry product than both hot air dry and solar dry products. 
However, in this study all the test treatments received the same drying method. The 
high %MC and the similarity between samples from papain 0.004g + vinegar 2.5% 
(T5), papain 0.04g +vinegar 5% (T9), papain 0.04g +vinegar 2.5% (T6), vinegar 5% 
(T7) and papain 0.004g+vinegar 5% (T8)may be due to the presence of vinegar. Since 
all treatments containing vinegar only recorded a higher %MC rehydration than that 
of control samples and papain only treatments. The above treatments probably had 
little or no shrinkage and a higher porous structure leading to a higher rehydration of 
samples. On the other hand, samples from papain 0.004g + vinegar 2.5% (T5) 
recorded a higher %MC compared with papain 0.04g +vinegar 5% (T9) and both 
treatments differed in %MC rehydration. 
 
Rehydration was halted at 300min due to loss of meat firmness, as some parts of the 
meat samples started to wear off (leached) during rehydration, especially samples 
from papain 0.004g (T2) and papain 0.04g (T3).All the treatments were not able to 
fully rehydrate to the moisture content of the fresh weight. Okos et al. (2007) reported 
that it is not possible to completely rehydrate a dried material to its fresh weight. 
 
 
 
 
 
 
 
 
86 
 
CHAPTER SIX 
6.0 Summary, Conclusions and Recommendations 
6.1 Summary 
Majority of animals slaughtered in Ghana for meat consumption are over aged and 
meats from such animals are tough and difficulty to chew when cooked. The 
toughness of the meat is due to increased collagen cross- linking which increases with 
age. Since jerky is dried to a low water activity in order to inhibit microbial growth, it 
is expected that using whole muscle from over aged animals would result in very 
tough and coarse textured jerky. Additionally, despite the low water activity there 
have been several reports of the outbreak of food borne diseases associated with the 
consumption of jerky. Marinades are known to enhance eating quality and extend 
shelf life of processed meat products.  This study investigates the potential of using 
marinades to produce jerky products that are microbiologically safe with desired 
sensory quality. The objectives of this study were to: 
a. Evaluate the effect of vinegar and papain marinades on sensory characteristics 
of the chevon jerky,  
b. Compare the effect of the treatments on microbial characteristics and shelf life 
of chevon jerky during storage. 
 
A 3x3 factorial design with three papain levels: (0, 0.004g and 0.04g (w/v)) and three 
vinegar levels (0, 2.5% and 5% (v/v)) were used to test the combinatorial 
concentration effect on quality characteristics of the chevon jerky. The experiment 
composed of nine treatments with three replications. Samples were marinated for 12h 
o
and dried in an oven for 10h at temperature of 65 C. The parameters measured 
included sensory and microbial quality characteristics as well as drying and 
87 
 
rehydration ratio. The samples for sensory and microbial test were vacuum packaged 
and stored at room temperature. 
 
Sensory evaluation was conducted on samples stored for 1d and 15d. Meat samples 
were presented to trained panelists in plastic containers marked with 3-digit codes. 
Tenderness, chewiness, juiciness, flavour and overall liking of the samples were 
evaluated using 8 point hedonic scale. Microbial quality analysis was conducted at 1d, 
15d and 30d of storage. Effects of the nine treatments on the growth of four different 
microbes (total plate count, Staphylococcus aureus, E.coli, yeast and mould) during 
storage were investigated. Drying rate (% moisture content) was determined by 
weighing samples before drying and every 1h during drying. The samples were dried 
for 10h. The loss in weight of the sample was calculated and hence its moisture 
content was obtained. Moisture content (%) during rehydration was carried out on 
sample to distilled water ratio of 1:40 for 300min under ambient condition. The 
sample was withdrawn from the distilled water every 30min and excess water was 
carefully removed by blotting with a tissue paper, before weighing. The result of 
sensory properties showed that out of the nine treatments tested, papain (0.04g) was 
effective in tenderising the chevon jerky compared with all the other treatments. 
Samples were ranked as very tender to extremely tender while samples treated with 
vinegar (5%) was ranked as moderately tough to slightly tough. With regard to 
acceptability, samples from control obtained the highest acceptability score. Panelists 
ranked the control treatments between ―very like to extremely like‖ No significant (p 
<0.05) difference were observed among treatments for chewiness, juiciness and 
flavour. However, juiciness improved as storage time progressed from 1d to 15d. 
88 
 
With microbial tests, no significant (p > 0.05) difference were observed among 
marinade treatments for all the four target organisms (total plate count, 
Staphylococcus aureus, E.coli, yeast and mould) tested. However, there was a 
reduction in microbial counts among all the test treatments as storage period 
progressed from 1d to 30d which was due to the low moisture content in the chevon 
jerky products and the anaerobic conditions (vacuum packaging) which inhibited 
microbial growth. 
 
Samples from lower concentration of vinegar (2.5%) recorded the least percent 
moisture content of 1.71% after drying, whereas the highest (3.61%) was observed in 
control samples. The low moisture content attests to the lack of effect of the 
treatments on chewiness and also low microbial counts that was recorded in all the 
test samples. 
 
Finally, all the treatments were not able to fully rehydrate to the moisture content of 
the fresh weight which may suggest a significant structural disruption of myofibrillar 
proteins due to the duration of drying. However, samples from control recorded the 
least percent moisture uptake (%MC) of 9.83 whereas samples from lower 
concentration of vinegar 2.5% recorded the highest %MC (19.94) after rehydration. 
 
 
 
89 
 
6.2 Conclusions 
Conclusions drawn from the results: 
a. Papain at higher concentration (0.04g) resulted in a tenderer chevon jerky 
compared with all the other treatments and was ranked by panelists as ―very 
tender to extremely tender‖.  
b. Vinegar had no effect on tenderness at the concentrations tested.  
c. Marinade treatments tested, diminished the overall likeness of chevon jerky 
since samples from control were ranked by panelists as ―very like‖ to 
―extremely like‖ whiles the rest of the treatments were ranked as ―slightly 
like‖ to ―moderately like‖, the marinades did not have effect on any of the 
microbial counts (total plate count, Staphylococcus aureus, E. coli and yeast 
and mould) that were tested,  
d. Microbial count (Staphylococcus aureus, E. coli and yeast and mould) 
decreased with increasing storage time up to 30d. 
 
 
6.3 Recommendations 
Control samples were more preferred compared with marinade treated jerky; 
however, it is possible to improve meat toughness using papain to produce meat with 
acceptable sensory attributes than vinegar. 
Marinade treatments were not able to inhibit microbial growth, however vinegar can 
be added to introduce variety and enhance jerky flavour. 
Further research should be carried out in beef, since cattle are slaughtered at a much 
older age than goats. Also further research should be carried out on the shelf life 
studies with a much extended storage time. 
90 
 
REFERENCES 
Aaslyng, M. D., Bejerholm, C., Ertbjerg, P., Bertram, H. C. and Andersen, H. J. 
(2003). Cooking loss and juiciness of pork in relation to raw meat quality and 
cooking procedure. Food Quality and Preference. 14: 277–288.  
 
Ablordeppey, S. D., and Osabutey, F. (2015, November 14). Samuel Doe 
Ablordeppey. Retrieved November 14, 2015, from 
http://www.graphic.com.gh/news/general-news/4-ministries-allocated-gh-2-
59-billion-in-2016.html.  
 
Ackerman, S. A., C. E. Cohen, C. Swift, and R. Benedict. (1981). Evaluation of the 
press method for ―frankfurter‖ juiciness estimation. Fleischwirtsch 61: 1169-
1170. 
 
Adams, M. R. and Moss, M. O. (1995). Food Microbiology. Royal Society of 
Chemistry, UK. pp 18-45.  
 
Aehle, W. (2007). Enzymes in industry, production and applications. Weinheim: 
Wiley-VCH Verlag GmbH and Co.pp517. 
 
Aguirrezábal, M. M., Mateo, J., Domínguez, M. C and Zumalacárregui, J. M. (2000). 
The effect of paprika, garlic and salt on rancidity in dry sausages. Meat 
Science. 54: 77–81. 
 
Ajandouz, E. H., Desseaux, V., Tazi, S. and Puigserver, A. (2008). Effects of 
temperature and pH on the kinetics of caramelisation, protein cross-linking 
and maillard reactions in aqueous model systems. FoodChemistry.107 (3): 
1244-1252. 
 
Aktaş, N. and Kaya, M. (2001). Influence of weak organic acids and salts on the 
denaturation characteristics of intramuscular connective tissue. A differential 
scanning calorimetry study. Meat Science. 58: 413–419.  
 
Albright, S. N., Kendall, P. A., Avens, J. S. and Sofos, J. N. (2000). Sensoryproperties 
of beef jerky processed under various conditions.In Proceedings of IFT annual 
meeting, June 10-14,Dallas, TX, USA, Session 11. 
 
Allen, K., Cornforth, D., Whittier, D., Vasavada, M. and Nummer, B. 
(2007).Evaluation of high humidity and wet marinade methods for 
pasteurisation of jerky. Journal of Food Science. 72(7): 351–355.  
 
Alvarado, C. and McKee, S. (2007). Marination to improve functional properties and 
safety of poultry meat. The Journal of Applied Poultry Research 16:113–120. 
 
Andersen, H. J. and Skibsted, L. H. (1991). Oxidative stability of frozen pork patties. 
Effect of light and added salt. Journal of Food Science.56: 1182–1184.  
 
 
91 
 
An, K., Ding, S., Hongyan Tao, Zhao, D., Wang, X., Wang, Z. and Hu, X. 
(2012).Response surface optimisation of osmotic dehydration of Chinese 
ginger (Zingiber officinale Roscoe) slices. International Journal of Food 
Science and Technology. 48: 28–34. 
 
Arakawa, T., Prestrelski, S. J., Kenney, W. C. and Carpenter, J. F. (2001). Factors 
affecting short-term and long-term stabilities of proteins. Advanced Drug 
Delivery Reviews. 46 (1-3): 307–326. 
 
Arason, S. (2003). The drying of fish and utilisation of geothermal energy; the 
Icelandic experience. International Geothermal Conference, Reykjavik. Paper 
076. 
 
Arboix, A. A. (2004). Ham production: cooked ham. In: Encyclopedia of Meat 
st
Sciences. (Editiors.W. Jensen, C. Devine, M. Dikeman), 1  edition. Elsevier, 
Oxford, pp 557–567. 
 
Ashie, I. N. A., Sorensen, T.L. and Nielsen, P.M. (2002).Effects of Papain and a 
microbial enzyme on meat proteins and beef tenderness. Journal of Food 
Science. 67: 2138–2142.  
 
Azarkan, M., El Moussaoui, A., van Wuytswinkel, D., Dehon, G. and Looze, Y. 
(2003). Fractionation and purification of the enzymes stored in the latex of 
Carica papaya. Journal of Chromatography B. 790: 229–238.  
 
Bagamboula, C. F., Uyttendaele. M. and  Debevere.J. (2004). Inhibitory effect of 
thyme and basil essential oils, carvacrol, thymol, estragol, linalool and 
pcymene towards Shigella sonnei and S. flexneri. Food Microbiology. 21: 33-
42.  
 
Barbut, S. H., Draper, H.  and Hadley. M. (1989). Lipid oxidation in chicken nuggets 
by meat type, phosphate, and packaging.Journal of Food Protection. 
52(1):55–58.  
 
Beauchat, L. R. (1981). Microbial stability as affected by water activity. Cereal Foods 
World.26(7):345-349. 
 
Behrends, J. M., Goodson, K. J., Koohmaraie, M., Shackelford, S. D., Wheeler, T. L., 
Morgan, W.W., Reagan, J. O., Gwartney, B. L., Wise, J. W. and Savell, J.W. 
(2005).Beef customer satisfaction: Factors affecting consumer evaluation of 
calcium chloride-injected top sirloin steaks when given instructions for 
preparation. Journal of Animal Science. 83: 2869.  
 
Bejerholm, C. And Asalyng, M. D. (2004). Cooking of Meat. In: Werner Klinth, J. 
(Editor). Encylopedia of Meat Science. Oxford: Elsevier. pp342 – 349. 
 
Bell, M. (1996). Just jerky. The complete guide to making it. Madison, W. I: The Dry 
Store Publishing Company. pp 39. 
 
92 
 
Berge, P., Ertbjerg, P., Larsen, L. M., Astruc, T., Vignon, X. and Moller, A. J. (2001). 
Tenderisation of beef by lactic acid injected at different times post mortem. 
Meat Science. 57: 347–357.  
 
Berry, B. W. (1993). Tenderness of beef loin steaks as influenced by marbling level 
removal of subcutâneous fat and cooking method. Journal of Animal 
Science.71:2412-2419. 
 
Bhaisare, D.B., Thyagarajan D., Churchi,l R.R., Punniamurthy, N.(2014). Bacterial 
Pathogens in Chicken Meat: Review. International Journal of Life Sciences 
Research, 2, (3), 1-7. 
 
Binkerd,E. F. and Kolari, O. E. (1975).The history and use of nitrate and nitrite in 
curing of meat.Food and Cosmetics Toxicology. 13:655–661.  
 
Borowski, A. G., Ingham, S. C. and Ingham, B. H. (2009). Validation of ground and 
formed beef jerky processes using commercial Lactic acid bacteria starter 
cultures as pathogen surrogates. Journal of Food Protection. 72(6):1234–
1247.  
 
Bratzler, L. J. (1971). Palatability factors and evaluation. In: The Science of Meat and 
Meat Products, 2nd edition. (Editors. J. F. Price and B. S. Schweigert). 
Freeman.W. H. San Francisco, Calif. pp. 328-348 
 
Briskey, E. J., and Kauffman, R. G. (1971). Quality characteristics of muscle as food. 
In: The Science of Meat and Meat Products.(Editors. J. Price and B. S. 
Schweigert).W. H. San Francisco, Calif. pp. 367.  
 
Burke, R.M. and Monahan, F.J. (2003).The tenderisation of shin beef using a citrus 
juice marinade. Meat Science. 63(2): 161–168.  
 
 
Calhoun, C. M., Eilert, S. J. and Mandigo, R. W. (1996). Connective tissue/Acidic 
phosphate pre- blend effects on reduced fat ―frankfurters‖. Journal of Food 
Science. 61: 459–464.  
 
Calicioglu, M., Kaspar, C.W., Buege, D. R. and Luchansky, J. B. (2002). 
Effectiveness of spraying with Tween 20 and Lactic acid to decontaminate 
inoculated E. coli O157 and indigenous E. coli biotype I on beef.Journal of 
Food Protection. 65: 26–32.  
 
Calicioglu, M., Sofos, J. N. and Kendall, P. A. (2003).Fate of acid-adapted and non-
adapted Escherichia coli O157: H7 inoculated post-drying on beef jerky 
treated with marinades before drying. Food Microbiology. 20: 169–177.  
 
Calkins, C. R. and. Hodgen, J. M. (2007). A fresh look at meat flavour.Meat Science. 
77:63-80. 
 
Calkins, C. R and Sullivan, G. (2007). Ranking of beef muscles for tenderness. Beef 
facts. Product enchancement. National Cattlemen‘s beef Associsation. 
93 
 
Available: http://beefcentral.com/u/lib/cms/ranking-of-beef-muscles-for-
tenderness.pdf (2012 May 20). 
 
nd
Carlile, M. J., Watkinson, S. C. and Gooday, G.W. (2001). ―The Fungi‖ 2  edition. 
Academic Press: London, UK. pp 588. 
 
Carpenter, Z. L. (1962). The histological and physical characteristics of pork muscle 
and their relationship to quality. Ph.D.University of Wisconsin, Madison. 
 
CDC, (1995). Centres for Disease Control and Prevention. Outbreak of Salmonellosis 
associated with beef jerky – New Mexico. Morbid Mortal Weekly Rep. 
44:785-788. 
 
Chen, Q. H., He, G. Q., Jiao, Y. C and Ni, H. (2006). Effect of elastase from a 
Bacillus strain on the tenderization of beef. Food Chemistry. 98: 624 – 629. 
 
Chem, C. M., Huffman, D. L., Egbert, W. R. and Smith, R. C. (1992). Oxidation of 
purified bovine myoglobin – effects of Ph, sodium – chloride, sodium 
tripolyphosphate, and binders. Journal of Agricultural and Food 
Chemistry.40: 1767 – 1771. 
 
Choi, K. S., Choi, J. D., Chung, H. C., Kwon, K. I., Im, M. H., Kim, Y. H. and Kim 
W. S. (2000).Effects of mashing proportion of soybean to salt brine on 
Kanjang(soy sauce) quality. Journalof Food Science and Technology. 32:174-
180. 
 
Choi, J. H., Jeong, J. Y., Han, D. J., Choi, Y. S., Kim, H. Y., Lee, M. A., Lee, E. S., 
Paik, H. D., and Kim, C. J. (2008). Effects of pork/beef levels and various 
casings on quality properties of semi-dried jerky. Meat Science. 71: 278-286. 
 
Choi, Y. S., Jeong, J. Y. and Lee, M. A. (2007). Effect of packaging methods on the 
quality of Korea Style, beef and pork jerky during storage. Korean Journal of 
Food Science of Animal Resource.27 (3): 290 – 298. 
 
Christensen, M. (2009). Injection of marinade with actinidin increases tenderness of 
porcine M. biceps femoris and affects myofibrils and connective tissue. 
Journal of Science of Food Agriculture.89(9): 1607-1614. 
 
Christensen, L., Ertbjerg, P., Aaslyng, M. D. and Christensen, M. (2011). Effect of 
prolonged heat treatment from 48°C to 63°C on toughness cooking loss and 
colour of pork. Meat science. 88(2): 280-285. 
 
Cohen, J.S. and Yang, T.C.S. (1995). Progress in food dehydration. Trend in Food 
Science and Technology.(6):20 -25. 
 
Corriher, S. (2012). Marinades add flavour but don‘t always tenderise – fine cooking 
recipes, techniques and tips. The Taunton Press. 
http;//www.finecooking.com/articles/marinades – flavour – tenderise. Aspx. 
Retrieved 28 November. 
 
94 
 
Corry, J. E. L. (1978). Relationships of water activity to fungal growth. In: Food and 
Beverage Mycology. (Editor. L. R. Beuchet). AVI Publish Company, USA. 
pp45-82. 
 
Cross, H. R. (1987). Sensory Characteristics of Meat. Part 1, Sensory Factors and 
rd
Evaluation. In: The Science of Meat and Meat Product 3  edition. (Editors. J. 
F. Price and B. S. Schwergert). Westport, CT: Food and Nutrition Press, Inc. 
pp. 307 –330. 
 
Davey, C. L. (1974). Temperature-dependent cooking toughness in beef.Journal of 
Science of Food and Agriculture. 25(8): 931-938. 
 
Davidson, P.M. (2001). Chemical preservatives and natural antimicrobial compounds. 
nd
In: Food Microbiology:Fundamentals and Frontiers. 2  edition. (Editors. M. 
P. Doyle, L. R. Beuchat andT. J. Montville). ASM Press, Washington, DC. pp 
539 – 627. 
 
Deng, Y., Luo, Y., Wang, Y., Yue, J., Liu, Z., Zhong, Y., Zhao, Y. and Yang, H. 
(2014).Drying-induced protein and microstructure damages of squid fillets 
affected moisture distribution and rehydration ability during 
rehydration.Journal of Food Engineering. 123: 23–31. 
 
Derrickson-Tharrington, E. L. (2001). Evaluation of common acidulants for 
enhancement of destruction of Escherichia coli O157:H7 during drying of 
Gala apple slices and whole muscle beef jerky. M.S. thesis.Colorado State 
University, Fort Collins. 
 
Dickson, J. S., Cutter, C. G. N and Siragusa, G. R. (1994). Antimicrobial effects of 
trisodium phosphate against bacteria attached to beef tissue. Journal of Food 
Protection. 57: 952–955.  
 
Djeri, N.  (2007). Development and evaluation of raw and pre-cooked vacuum 
packaged goat meat product. M.S. thesis.University of Florida. 
 
Doneva, M., Miteva, D., Dyankova, S., Nacheva, I., Metodieva, P. and Dimov, K. 
(2015).Efficiency of plant proteases bromelain and papain on turkey meat 
tenderness. Biotechnology in Animal Husbandry. 31(3):407–413.  
 
Doyle, M.E. and Glass, K.A. (2010).Sodium reduction and its effect on food safety, 
food quality, and human health. Comprehensive Reviews in Food Science and 
Food Safety. 9: 44–56. 
 
Doymaz, I and Smail, O. (2011). Drying characteristics of sweet cherry,‖ Food and 
Bioproducts Processing, vol. 89, no. 1, pp. 31–38. 
 
Dransfield, E. and Etherington, D. (1981). Enzymes in the tenderisation of meat. In: 
Enzymes and Food Processing. (Editors. G.G. Birch,N. Blakebrough and K. 
J.Parker). Applied Science Publishers, London.pp 177-194. 
 
95 
 
Easy Recipe. (2014). Is it necessary to add water when making jerky? Retrieved 
February 9, 2017, from http://www.hicountry.com/?s=jerky. 
 
Edward, S. D. and Pauline, E. M. (1965). Comparison of beta-carotene content of 
dried carrots prepared by three dehydration process. Food Technology (19): 
1597-1603. 
 
Egan, A. F., Ford, A. L., Shay, B. J. (1980). A comparison of micro-bacterium 
thermo-spectrumand Lactobacilli as spoilage organisms of vacuum - packaged 
sliced luncheon meat. Journal of Food Science. 45:1745–1748. 
 
Eidson, M., Sewell C. M, Graves G. and Olson R. (2000). Beef jerky gastroenteritis 
outbreaks. Journal of Environmental Health 62: 9 - 13. 
 
Ellis, D. I. and Goodacre, R.(2001). Rapid and quantitative detection of the microbial 
spoilage of muscle foods: Current status and future trends. Trends Food 
Science. Technology.12:414-424. 
 
Ertbjerg, P., Mielche, M. M., Larsen, L.  M and Moller, A.  J. (1999). Relationship 
betweenproteolytic changes and tenderness in prerigor lactic acid marinated 
beef. Journal of Science Food Agriculture. 79: 970–978. 
 
Etherington, D.J. (1974).The purification of bovine cathepsin B1 and its mode of 
action on bovine collagens. Biochemistry Journal. 137: 547–557 
 
Etherington, D.J. (1984).The contribution of proteolytic enzymes to postmortem 
changes in muscle. Journal of Animal Science. 59: 1644 – 1650. 
 
Faith, N. G., Le Coutour, N. S., Alvarenga, M. B., Calicioglub, M., Buegeb, D. R. and 
Luchansky, J. B. (1998). Viability of Escherichia coli O157:H7 in ground and 
formed beef jerky prepared at levels of 5 and 20% fat and dried at 52, 57, 63, 
or 68˚C in a home-style dehydrator. International Journal of Food 
Microbiology.41: 213-221. 
 
FAO, (1990). Food Agriculture Organisations of the United Nations. Manual on 
simple methods of food preservation. FAO Animal Production and Health, 
Rome.Paper no 79. 
 
Farmer, L. J. (1994). The role of nutrients in meat flavour formation. Proceedings of 
the Nutrition Society. 53(02): 327–333.  
 
Feiner, G.  (2006). Meat products handbook: Practical Science and Technology. 
Woodhead Publishing Limited Cambridge, England. pp 142 – 157. 
 
Fernández-Ginés, J. M., Fernández-López, J., Sayas-Barberá, E. and Pérez-Alvarez, J. 
A. (2005). Meat products as functional foods: A review. Journal of Food 
Science. 70(2):37–43. 
 
Fleet, G. (1999). Microorganisms in food ecosystems. International Journal of Food 
Microbiology. 50: 101–117. 
96 
 
 
Fogle, D. R., Plimptong, R. F., Ockerman, H. W., Jarenback, L., Persson, T. (1982). 
Tenderisation of beef: Effect of enzyme, enzyme level and cooking method. 
Journal of Food Science. 47:1113–1118. 
 
Foegeding, E. A. and D. K. Larick. (1986). Tenderisation of beef with bacterial 
collagenase. Meat Science. 18:201-214. 
 
Foster, R. J. (2004). Meeting consumer expectations. Food Product Design. Available 
at: http://www.foodproductdesign.com/articles/1204CS.html .Virgo 
Publishing, Phoenix, AZ. 
 
FSIS, (2011). Food Safety and Inspection Service. Jerky and Food safety. Food Safety 
and Inspection Service, United States Department of Agriculture, Washington, 
DC, USA. Available from: http://www.fsis.usda.gov/ 
Fact_Sheets/Jerky_and_Food_Safety/index.asp#1. Modified Nov. 15, 2011. 
 
Froning, G. W. and Sackett, B. (1985).Effect of salt and phosphates during tumbling 
of turkey breast muscle on meat characteristics.Poultry Science. 64: 1328–
1333. 
 
Fu, H.-Y. and Ho, C.-T. (1997). Mechanistic studies of 2-(1-Hydroxyethyl)-2, 4,5-
trimethyl-3- oxazoline formation under low temperature in 3-Hydroxy-2-
butanone/ammonium acetate model systems. Journal of Agricultural and 
Food Chemistry. 45(5): 1878–1882.  
 
Gao, T., Li, J., Zhang, L., Jiang, Y., Song, L., Ma, R., Gao, F. and Zhou, G. 
(2015).Effect of different tumbling marinade treatments on the water status 
and protein properties of prepared pork chops. Journal of the Science of Food 
and Agriculture. 95(12): 2494–2500. 
 
García-Pascual, P., Sanjuán, N., Bon, J., Carreres, J.E. and Mulet, A. (2005). 
Rehydration process of Boletus edulis mushroom: Characteristics and 
modelling. Journal of the Science of Food and Agriculture. 85(8): 1397–1404. 
 
Gault, N.F.S. (1985).The relationship between water-holding capacity and cooked 
meat tenderness in some beef muscles as influenced by acidic conditions 
below the ultimate pH. Meat Science. 15: 15–30. 
 
Geesink, G., Sujang, S. and Koohmaraie, M. (2011).Tenderness of pre and post rigor 
lamb Longissimus muscle. Meat Science. 88(4):723–726 
 
Gerelt, B., Ikeuchi, Y. and Suzuki, A. (2000). Meat tenderisation by proteolytic 
enzymes after osmotic dehydration.Meat Science. 56(3):311–318. 
 
Ghaly, A. E., Dave, D.  Budge, S. and Brooks, M.S. (2010). A review: Fish spoilage 
mechanisms and preservation techniques. American Journal of Applied 
Sciences. 7:846–864. 
97 
 
Gillett, T., Cassidy, R. and Simon, S. (1982).Ham massaging: effect of massaging 
cycle, environmental temperature and pump level on yield, bind and colour of 
intermittently massaged hams. Journal of Food Science. 47(4):1083–1088.  
 
Goli, T., Abi Nakhoul, P., Zakhia-Rozis, N., Trystram, G. and Bohuon, P. 
(2007).Chemical equilibrium of minced turkey meat in organic acid solutions. 
Meat Science. 75(2):308–314. 
 
Gourama, H. and Bullerman, L. B. (1995). Relationship between aflatoxinproduction 
and mould growth as measured by ergosterol and plate count.LWT - Food 
Science and Technology. 28,(2), pp. 185 –189 
 
Griffiths, G., Trueman, L., Crowther, T., Thomas, B. and Smith, B. (2002).Onions? A 
global benefit to health. Phytotherapy Research. 16(7):603–615 
 
Gutierrez, J., Barry-Ryan, C. and Bourke, P. (2009).Antimicrobial activity of plant 
essential oils using food model media: Efficacy, synergistic potential and 
interactions with food components. Food Microbiology. 26: 142–150. 
 
Hamm, R. (1975). Water-holding capacity of meat. In: Meat.(Editors. D. J. A. Cole 
and R. A. Lawrie). Butterworths: London, UK. pp 321-337. 
 
Hamm, R. and Deatherage, F. E.(1960). Changes in hydration, solubility and charges 
of muscle proteins during heating of meat. Journal of Food Science. 
25(5):587–610. 
 
Han, D.-J., Jeong, J.-Y., Choi, J.-H., Choi, Y.-S., Kim, H.-Y., and Lee, M.-A. 
(2007).Effects of drying conditions on quality properties of pork jerky. Korean 
Journal of Food Science of Animal Research. 27:29–34. 
 
Harper, G.S. (1999).Trends in skeletal muscle biology and the understanding of 
toughness in beef. Australian Journal of Agricultural Research. 50(7): 1105 - 
1129. 
 
Harrison, J.A, Harrison, M. A. and Rose, R. A.(1997).Fate of Listeriamonocytogenes 
and Salmonella species in ground beef jerky. Journal of Food Protection. 
60:1139–1141. 
 
Harrison, J.A. and Harrison, M.A. (1996).Fate of Escherichia coli O157: H7, Listeria 
monocytogenes, and Salmonella typhimurium during preparation and storage 
of beef jerky. Journal of Food Protection. 59:1336–1338. 
 
Hayes, J.E., Kenny, T.A., Ward, P. and Kerry, J.P. (2007).Development of a modified 
dry curing process for beef. Meat Science. 77:314–323. 
 
Hinkle, J. B. (2010).Acid marination for tenderness enhancement of beef bottom 
round.  M.S. Thesis.University of Nebraska - Lincoln.  
 
Holdsworth, S. D. (1971). Dehydration of food products. A review International 
Journal of Food Science and Technology. 6:331–370. 
98 
 
Holley, R. A. (1985).Beef jerky: Fate of Staphylococcus aureus in marinated and 
corned beef during jerky manufacture and 2.5°C storage.Journal of Food 
Protection. 48: 107–111. 
 
Honikel, K. O. (1998). Reference methods for the assessment of physical 
characteristics of meat.Meat Science. 49(4):447–457. 
 
Horowits, R., Kempner, E. S., Bisher, M. E. and Podolsky, R. J. (1986).A 
physiological role for titin and nebulin in skeletal muscle. Nature. 323(6084): 
160–164. 
 
Hotchkiss, H. J. and Potter, N. J. (1995). Meat preservation and processing. Food 
th
Science 5  Edition New York. pp:261 – 265.  
 
How to make jerky (2017). Retrieved February 9, 2017, from 
http://www.meatprocessingproducts.com/how-to-make-jerky.html.  
 
Huang, T. C. and Ho, C. T. (2001). Flavours of meat products. In: Meat Science and 
Applications. (Editors. O. A. Young, R. W. Rogers, Y. H. Hui, and W.-K. 
Nip). CRC Press. Retrieved from 
http://dx.doi.org/10.1201/9780203908082.ch4. Retrieved 2011/08/27. 
 
Huff-Lonergan, E., Parrish, F. C. and Robson, R. M. (1995).Effects of postmortem 
aging time, animal age and sex on degradation of titin and nebulin inbovine 
Longissimus muscle. Journal of Animal Science. 73: 1064 - 1073. 
 
Huffman, K. L., Miller, M. F., Hoover, L.C., Wu, C. K., Brittin, H. C. and Ramsey, 
C.B. (1996). Effect of beef tenderness on consumer satisfaction with steaks 
consumed in the home and restaurant. Journal of Animal Science. 74: 91- 97. 
 
Hui, Y.H., Aalhus, J. J., Cocolin, L., Guerrero – Legarreta, I., Nollet, L.M., Purchas, 
R.W., Schilling, M.W., Stanfield, P. and Xiong, Y. L (2012). Hand book of 
nd
Meat and Meat Processing. 2  edition, pp 508. 
 
Hui, Y. H. and Yiu. (2004).Handbook of Frozen Foods. New York, NY: Marcel 
Dekker Inc. pp17-23.  
 
Hung, Y., Liu, J. H. and Chou, R – G. R. (2013). Effects of Aspergillus oryzae 
proteases on postmortem degradation of Taiwan black pig myofibrillar 
proteins. Journal of Chinese Society of Animal. Science. 42 (1): 15 – 25. 
 
Hutton, C.W., Neggers, Y. H. and Love, T.O. (1981).Scanning electron microscopy, 
proteolytic enzyme activity and acceptability of beef Semitendinosus cooked 
by microwaves and conventional heat. Journal of Food Science. 46: 1309–
1314. 
 
Hwang, I. H., Lin, C.W. and Chou, R.G.R. (2000).Effect of lactic or acetic acid on 
degradation of myofibrillar proteins in post-mortem goose (Anser anser) 
breast muscle. Journal of Science Food and Agriculture. 80: 231–236. 
 
99 
 
Igene, J. O., Farouk, M. M. and Akanbi, C. T. (1990).Preliminary studies on the 
traditional processing ofKilishi.Journal of Science Food and Agriculture. 
50:89–98. 
 
Iizuka, K. and Aishima, T. (1999).Tenderisation of beef with pineapple juice 
monitored by Fourier transform infrared spectroscopy and chemometric 
analysis. Journal of Food Science. 64: 973–977. 
 
Ingham,  S. C., Engel, R. A., Fanslau, M. A., Schoeller, E. L., Searls, G. A., Buege, 
D. R. and Zhu, J.  (2005). Fate of Staphylococcus aureus on vacuum-packaged 
ready-to-eat meat products stored at 21_C. Journal of Food Protection. 
68:1911–1915. 
 
Ingham, S. C., Searls, G., Mohanan, S. and Buege, D. R. (2006). Survival of 
Staphylococcus aureus and Listeria monocytogenes on vacuum-packaged beef 
jerky and related products stored at 21°C. Journal of Food Protection. 69(9): 
2263–2267. 
 
ICMSF, (1996). International Commission on Microbiological Specifications 
forFoods, International Union of Biological Societies. Microorganismsin 
foods. 5. Characteristics of microbial pathogens. Blackie Academic and 
Professional, London. 
 
IUBMB, (2009). International Union of Biochemistry and molecular biology on the 
nomenclature and classification of enzymes by the reactions they catalyse. 
 
Ionescu, A., Aprodu, I and Pascaru, G. (2008). Effect of papain and bromelin on 
muscle and collagen proteins in beef meat.Food Technology. 31:9-16. 
 
Irzynic, Z., Klimczak, K. and Michalowski, S. (1995).Freeze-drying of the black 
currant juice. Drying Technology. 13: 417–424. 
 
Istrati, D. (2008). The influence of enzymatic tenderisation with papain on functional 
properties of adult beef. Journal of Agroalimentary Processes and 
Technologies.14 (1):140-146. 
 
Jay, J.M. (1987). Meats, poultry, and seafoods. In ―Food and Beverage Mycology,‖ 
2nd Edition. (Editor. L.R. Beuchat) Van Nostrand Reinhold, New York. pp. 
155. 
 
Jay, J.M. (1992). Staphylococcal gastroenteritis. In: Modern food microbiology. 4th 
Edition. Van Norstrand Reinhold: New York, US. pp 455-478. 
 
Jay, J. M. (2000). Modern Food Microbiology. Aspen, Gaithersburg, Maryland, pp. 
63. 
 
Jay, J. M. (2005). Modern Food Microbiology. In: Jay J. M., Loessner, M. J., Golden, 
D. A, (editors). NY: Springer Science + Business Media, Inc. pp 67. 
 
100 
 
th
Jay, J. M., Loessner, M. J., Golden, D. A.(2008). Modern Food Microbiology. 7  
edition. Springer Science + Business Media, Inc. New York.pp 51. 
 
Jayaraman, K. S., Gupta, D. K. D. and Rao, N. B. (1990).Effect of pre - treatment 
with salt and sucrose on the quality and stability of dehydrated cauliflower. 
International Journal of Food Science and Technology. 25(1): 47–60. 
 
Jeremiah, L .E. (2001).Packaging alternatives to deliver fresh meats using short- or 
long-term distribution. Food Research International. 34: 749–772. 
 
Jung, S. W., Baek, Y. S., Kim, Y. S. and Kim, Y. H. (1994). Quality changes of beef 
jerky during storage. Korean Journal of Animal Science 36:683-697. 
 
Kang, C. K. and Rice, E. E. (1970). Degradation of various meat fractions by 
tenderising enzymes. Journal of Food Science. 35(5):563-565. 
 
Kannan, G., Kouakou, B., Terrill, T. H. and Gelaye, S. (2003).Endocrine, blood 
metabolite and meat quality changes in goats as influenced by short-term, 
preslaughter stress. Journal of Animal Science. 81: 1499 - 1507.  
 
Karel, M., Fennerma, O. R., and Lund, D. B. (1978). Physical Principles of Food 
Preservation, Marcel Dekker, Boston.pp255-328. 
 
Ke, S., Huang, Y., Decker, E. A. and Hultin, H. O. (2009). Impact of citric acid on the 
tenderness, microstructure and oxidative stability of beef muscle. Meat 
Science.82(1): 113–118. 
 
Keene, W. E.,Sazie, E., Kok, J., Rice, D. H., Hancock, D.D., Balan, V. K., Zhao,T. 
and Doyle, M. P.(1997).An outbreak of Escherichia coli O157: H7 infections 
traced to jerky made from deer meat. Journal of American Medical 
Association. 277: 1229–1231. 
 
Keey, R. B. (1975). Drying: Principles and Practice. Pergamon Press, Oxford, pp. 1-4. 
 
Killinger, K. M., Calkins, C. R., Umberger, W. J., Feuz, D. M. and Eskridge, K. M. 
(2004).Consumer sensory acceptance and value for beef steaks of similar 
tenderness, but differing in marbling level. Journal of Animal Science. 
82(11):3294. 
 
Kim, H.-J. and Taub, I.A. (1991).Specific degradation of myosin in meat by 
bromelain. Food Chemistry. 40: 337–343. 
 
Kim, M. H. (1990).Effects of pretreatments prior to conventional dehydration on 
dried product quality. Journal of Biochemistry Engineering. 4: 30-38. 
 
Kim, H. W., Hwang, K. E., Song, D. H., Kim, Y. J., Lim, Y. B., Choi, J. H., Choi, Y. 
S. and Kim, C. J. (2014). Effects of soy sauce on physicochemical and textural 
properties of tumbled chicken breast. Poultry Science. 93(3): 680–686. 
 
101 
 
Knight, P. and Parsons, N. (1988). Action of NaCl and polyphosphates in meat 
processing: Responses of myofibrils to concentrated salt solutions. Meat 
Science. 24(4): 275–300.  
 
Knipe, C. L. (2009). Processing interventions to inhibit Listeria monocytogenes 
growth in ready-to-eat meat products. In: Thermal processing of ready-to-eat 
st
meat products. 1 edition.(Editors C. L. Knipe and R. E. Rust). Blackwell 
Publishing: Columbus, OH,USA.pp87-126. 
 
Konieczny, P., Stangierski, J. and Kijowski, J. (2007). Physical and chemical 
characteristics and acceptability of home style beef jerky. Meat Science. 76: 
253–257. 
 
Koohmaraie, M., Babiker, A. S., Schroeder, A. L., Merkel, R. A. and Dutson, T. R. 
(1988). Acceleration of postmortem tenderisation in ovine carcasses through 
activation of Ca2+ dependent proteases. Journal of Food Science. 53:1638–
1641. 
 
2+
Koohmaraie, M. (1992).The role of Ca  dependent proteases (calpains) in post 
mortem proteolysis and meat tenderness. Biochemistry. 74: 239–245. 
 
Krokida, M.K. and Marinos-Kouris, D. (2003).Rehydration kinetics of dehydrated 
products. Journal of Food Engineering. 57(1): 1–7. 
 
Kropf, D. H. (2004) Packaging. In: Encyclopedia of Meat Sciences. (Editors. W. K. 
rd
Jensen, C. Devine, M. Dikeman). 3 edition. Elsevier Ltd:Oxford, UK.pp. 943-
976.  
 
Kwak, E. and Lim, S. (2004).The effect of sugar, amino acid, metal ion, and NaCl on 
model Maillard reaction under pH control. Amino Acids. 27(1):85 – 90. 
 
Labadie, J. (1999). Consequences of packaging on bacterial growth. Meat is an 
ecological niche. Meat Sci.52:299-305. 
 
Labelle, R. L. and Moyer, J. C. (1966). Dehydro - freezing red tart cherries. Food 
Technology. 20:1345-1352. 
 
Latif, S. (2011). Effect of marination on the quality characteristics and microstructure 
of chicken breast meat cooked by different methods. Seria zootehnie 
lucrative54: 314-324. 
 
th
Lawrie, R. A. (1998). Meat science. In: The eating quality of meat. 6  
edition.Woodhead Publishing Limited, Cambridge. Chap10, pp 229. 
 
Lawrie, R. A. and Ledward, D. A. (2006). Lawrie's Meat Science. 7th 
Edition.Woodhead Publishing Ltd, Cambridge: England and CRC Press Boca 
Raton, New York, Washington DC. pp 75 – 155. 
 
102 
 
Lazarides, H.N., Katsanidis, E. and Nickolaidis, A. (1995). Mass transfer kinetics 
during osmotic preconcentration aiming at minimal solid uptake. Journal of 
Food Science. 25: 151–166. 
 
Lee, S. J. and Park, G. S. (2004). The quality characteristics of beef jerky prepared 
with various spices. Journal of Food Cookery Science.20:489-497. 
 
Leistner, L. (1987). Shelf stable product and intermediate moisture foods based on 
meat. In: Water activity theory and application to food. (Editors. L. Rockland 
andL. B. Beuchat) Marcel Dekker Inc., New York, pp. 295-328. 
 
Leistner, L., Rodel, W. and Krispien, K. (1981). Microbiology of meat and meat 
products in high and intermediate moisture ranges. In: Water Activity: 
Influences on Food Quality. (Editors. L.B. RocklandandG. F. 
Stewart).Academic Press, New York. pp 855. 
 
Lemos, A. L. S. C., Nunes, D. R. M. and Viana, A. G. (1999).Optimisation of the 
still-marinating process of chicken parts. Meat Science. 52(2): 227–234. 
 
Lewicki, P. P. (1998).Some remarks on rehydration of dried food. Journal of Food 
Engineering. 36:81 – 87. 
 
Lewis, G. J. and Purslow, P. P. (1991). The effect of marination and cooking on the 
mechanical properties of intramuscular connective tissue.Journal of Muscle 
Foods. 2:177–195. 
 
Lim, D.-G., Lee, S.-S., Seo, K.-S. and Nam, K.-C. (2012).Effects of different drying 
methods on quality traits of Hanwoo beef jerky from low-valued cuts during 
storage. Korean Journal of Food Science of Animal Resources, 32(5):531–
539. 
 
Lim, H. J., Jung, E.Y., Kim, G .D., Joo, S.T., Yang, H. S. (2013). Quality properties 
of beef jerky replaced salt with soy sauce, red pepper paste and soybean paste 
during storage. Korean Journal for Food Science and Animal Resources. 
33:181 – 188. 
 
Lorenzen, C. L., Miller, R. K., Taylor, J. F., Neely, T. R., Tatum, J. D., Wise, J. W., 
Buyck, M.J., Reagan, J.O. and Savell, J.W. (2003).Beef customer satisfaction: 
Trained sensory panel ratings and Warner-Bratzler shear force values. Journal 
of Animal Science. 81: 143 - 149. 
 
Lutalo- Bosa, A. J. And Macrae, H. F. (1969). Hydrolytic enzymes in bovine skeletal 
muscle, 3 activity of some catheptic enzymes. Journal of Food Science. 
34(5):401 – 404. 
 
Madruga, M. S., Arruda, S. G. B., Narain, N. and Souza, J. G. (2000). Castration and 
slaughter age effects on panel assessment and aroma compounds of the 
―mestiço‖ goat meat. Meat Science. 56(2):117–125. 
 
103 
 
Manteuffel-Gross, R. and Ternes, W. (2009). Effects ofmarination on the aroma of 
pan-fried wild boar meat – Part 1: Red wine Marinade. 24:55-59. 
 
Marsh, B. B. and Leet, N. G. (1966).Studies in meat tenderness. III. The effects of 
cold shortening on tenderness.Journal of Food Science.31: 450. 
 
Martens, H., Stabursvik, E. and Martens, M. (1982).Texture and colour changes in 
meatduring cooking related to thermal denaturation of muscle proteins.Journal 
of Texture Studies. 13(3): 291–309. 
 
Martin, M. (2001) Meat curing technology. In: Meat Science and Applications. Hui, 
Y.H., Nip, W.-K., Rogers, R.W. and Young, O.A. Editors. Marcel Dekker, 
New York. pp. 491-508. 
 
Mason, R. W., Taylor, M. A. J. and Etherington, D. J. (1984).The purification and 
properties of cathepsin L from rabbit liver. Biochemical Journal. 217: 209–
217. 
 
Maughan, C., Tansawat, R., Cornforth, D., Ward, R. and Martini, S. 
(2012).Development of a beef flavour lexicon and its application to compare 
the flavour profile and consumer acceptance of rib steaks from grass- or grain-
fed cattle. Meat Science. 90(1):116–121. 
 
McMinn, W. A. M. and. Magee, T. R. A. (1997). Quality and physical structure of 
dehydrated starch based system. Drying Technology.15(6-8):1961 -1971. 
 
Melton, S.L. (1990).Effects of feeds on flavour of red meat: A review. Journal of 
Animal Science. 68: 4421 – 4435. 
 
Meshram, S. K., Mendiratta S. K., Mishra, B. P., Sharma, B. D., Chand, S. and 
Prabhakaran, P. P. (2014). Effect of packaging on sensory quality of micro-
waved ready-to-eat mutton based snacks during storage. International Journal 
of Advancements in Research and Technology. 3: 2278-7763. 
 
Mikami, M., Whiting, A. H., Taylor, M. A. J., Maciewicz, R. A. and Etherington, D.J. 
(1987).Degradation of myofibrils from rabbit, chicken and beef by cathepsin l 
and lysosomal lysates. Meat Science. 21: 81–97. 
 
Miles, C.A., Burjanadze, T.V. and Bailey, A.J. (1995).The Kinetics of the thermal 
denaturation of collagen in unrestrained rat tail tendon determined by 
differential scanning calorimeter. Journal of Molecular Biology. 245: 437–
446. 
 
Miller, A. J., Strange, E. D. and Whiting, R. C. (1989). Improved tenderness of 
restructured beef steaks by a microbial collagenase derived from Vibrio B-
30.Journal of Food Science. 54(4):855–857. 
 
Miller, M. F., Carr, M. A., Ramsey, C. B., Crockett, K. L. and Hoover, L. C. (2001) 
Consumer thresholds for establishing the value of beef tenderness. Journal of 
Animal Science. 79(12): 3062 – 3068. 
104 
 
Miller, M. F., Davis, G. W., Ramsey, C. B. and Irizarry, H. (1996). Water activity 
theory and application to food. (Editors. L. B. Rockland and L. R. Beuchat). 
Marcel Dekker: New York, USA. pp. 295-328. 
 
Moeller, P. W., Fields, P. A., Dutson, T. R., Landmann,W. A. and Carpenter, Z. L. 
(1976). Effect of high temperature conditioning on subcellular distribution and 
levels of lysosomal enzymes.A research note. Journal of Food Science. 
41:216. 
 
Moeller, P. W., Fields, P. A., Dutson, T. R., Landmann, W. A.and Carpernter, Z. L.  
(1977). High temperature effects on lysosomal enzyme distribution and 
fragmentation of bovine muscle. Journal of Food Science. 42: 510–512. 
 
Montgomery, T. H. and Leheska, J. M. (2008). Effect of various management 
practices on beef-eating quality. 
 
Mori, K., Nishimura, T., Yasukawa, T. and Takahashi, K. (2001). Tenderisation of 
heated sliced beef by succinylated glycerol monostearate, a novel meat 
Tenderiser. Journal of Food Science. 66:524–529. 
 
Mottram, D.S. (1998).Flavour formation in meat and meat products: A review.Food 
Chemistry. 62: 415–424. 
 
Musonge, P. and Njolai, E.N. (1994).Drying and infusion during the traditional 
processing of kilishi. Journal of Food Engineering. 23:159–168. 
 
Naidoo, K. and Lindsay, D. (2010a). Pathogens associated with biltong product and 
their invitro survival of hurdles used during production. Food Protection 
Trends. 30: 532-538. 
 
Naidoo, K. and Lindsay, D. (2010b).Survival of Listeria monocytogenes and 
enterotoxin-producing Staphylococcus aureus and staphylococcus pasteuri 
during two types of biltong-manufacturing processes.Food Control. 21(7): 
1042–1050. 
 
Nayar, R, Mendiratta, S. K, Prabhakaran, P, Chand, S. and Beura, C. K. (2014). 
Comparison of hot air oven dried and microwave dried extended and 
dehydrated goat meat cubes. Research. Opinion. In Animal Veterinary 
Sciences, 4(6):336-342. 
 
Neyraud, E., Prinz, J. and Dransfield, E.  (2003).NaCl and sugar release, salivation 
and taste during mastication of salted chewing gum. Physiology and  
Behaviour. 79: 731–737. 
 
Nguyen, L., Gal, R. and Bunka, F. (2011).Use of phosphates in meat products.African 
Journal of Biotechnology.10(8):9874-9882. 
 
Nishimura, T., Hattori, A. and Takahashi, K. (1995).Structural weakening of 
intramuscular connective tissue during conditioning of beef. Meat Science. 
39:127–133. 
105 
 
 
Nishimura, T., Hattori, A. and Takahashi, K. (1999).Structural changes in 
intramuscular connective tissue during the fattening of Japanese black cattle: 
Effect of marbling on beef tenderisation. Journal of Animal Science. 77:93 – 
104. 
 
Nummer, B. A., Harrison, J. A., Harrison, M. A., Kendall, P., Sofos, J. N. and 
Andress, E.L.(2004). Effects of preparation methods on the microbiological 
safety of home-dried meat jerky.Journal of Food Protection. 67(10): 2337–
2341. 
 
Nychas, G. J. E., Skandamis, P. N., Tassou, C. C. and Koutsoumanis, K.P. 
(2008).Meat spoilage during distribution. Meat Science. 78: 77–89. 
 
Offer, G. and Knight, P. (1988). The structural basis of water-holding in meat. Part 1: 
General principles and water uptake in meat processing. In: Developments in 
Meat Science. (Editor. R. A Lawie). London: Elsevier Applied Science. pp 63-
171. 
 
Okos,  M. R.., Campanella, O., Narsimhan, G., Singh, R. K. and Weitnauer, A. 
nd
C.(2007). Food dehydration. In:Handbook of Food Engineering. 2  edition. 
(Editors. D. R. Heldman and D. B. Lund).Taylor and Francis Group, Boca 
Raton, Fla: USA.pp601- 743. 
 
Omojasola, P. F., Jilani, O. P. and Ibiyemi, S. A. (2008). Cellulase production by 
some fungi cultured on pineapple waste.Nature and Science 6(2): 64-79. 
 
Oreskovich, D. C., Bechtel, P. J., Mc Keith, F. K., Novakofski, J.  and Basgall, E. J. 
(1993). Marinade pH affects textural properties of beef. Journal of Food 
Science. 57: 305–311.  
 
Ockerman, H.  W. and Organisciak, C. S. (1978). Diffusion of curing brine in tumbled 
and non-tumbled porcine tissue. Journal of  Food Protection. 41:178–181. 
 
Ouali, A., Garrel, N., Obled, A., Deval, C., Valin, C. and Penny, I.F. 
(1987).Comparative action of cathepsins D, B, H, L and of a new lysosomal 
cysteine proteinase on rabbit myofibrils. Meat Science. 19:83–100. 
 
Park, C. J. and Park, C. S. (2007). The effects of drying method and spice extracts 
added to beef jerky on the quality characteristics of beef jerky. Korean 
Journal of Food Cookery Science. 23(4):800- 809. 
 
Parrish, F. C., Boles, J. A., Rust, R. E. and Olson, D. G. (1991).Dry and wet aging 
effects on palatability attributes of beef loin and rib steaks from three quality 
grades. Journal of Food Science. 56: 601–603. 
 
Pawar, V. D., Surve,V. D. and Machewad, G. M. (2003).Tenderisation of chevon by 
papain and trypsin treatments. Journal of Food Science Technology.40:296-
298. 
 
106 
 
Payne, C. T. (2009). Enzymes. In: Ingredients in Meat Products. Springer Nature, pp. 
173–198. Retrieved from http://dx.doi.org/10.1007/978-0-387-71327-48. 
 
Pearson, A. M. (1966). Desirability of beef its characteristics and their 
measurement.Journal of Animal Science. 25: 843. 
 
Pearson, A. M. and Gillett, T. A. (1999). Curing In: Processed meats. (Editors. A.M. 
Pearson and T.A. Gillett). Aspen Publication Inc: Gaithersburg, Maryland. pp 
448. 
 
Pearson, A. M. and Young, R. B. (1989). Composition and structure. In: Muscle and 
Meat Biochemistry (Editor. A. M. Pearson) pp 1-33. Academic Press: an 
Diego. 
 
Pegg, R. B., Amarowicz, R. and Code, W. E. (2006).Nutritional characteristics of emu 
meat and its value added products. Food Chemistry. 97: 193 - 202. 
 
Phillips, C. A. (1996). Review: Modified atmosphere packaging and its effects on the 
microbiological quality and safety of produce. Journal of Food Science 
andTechnology.31:463-479. 
 
Pietrasik, Z. and Shand, P. J. (2008). Effect of proteases from Bacillus subtilis and 
Aspergillus oryzae on the tenderness of beef. CMSA News March 2008. 
 
Pin, C. G., Fernando, G- De. and J. A. Ordonez, J. A. (2002). Effect of modified 
atmosphere composition on the metabolism of glucose by Brochothrix 
thermosphacta. Applied Environmental Microbiology.68:4441-4447 
 
Plimpton, R. F., Perkins, C. J., Sefton, T. L., Cahil, V. R. and Ockerman, H. W. 
(1991). Rigor condition, tumbling and salt level influence on physical, 
chemical and quality characteristics of cured, boneless hams. Journal of Food 
Science. 56:1514 - 1518. 
 
Poligne, I., Collignan, A. and Trystram, G. (2001). Characterisation of traditional 
processing of pork meat into Boucane. Meat Science. 599(4): 377–389. 
 
Priolo, A., Micol, D. and Agabriel, J. (2001). A review: Effect of grass feeding 
systems on ruminant meat colour and flavour. Animal Research 50(3): 185-
200. 
 
Purslow, P. P. (2005). Intramuscular connective tissue and its role in meat quality. 
Meat Science. 70: 435-447. 
 
Quintas, M., Guimarães, C., Baylina, J., Brandão, T. R. S. and Silva, C. L. M. (2007). 
Multiresponse modellingof the caramelisation reaction. Innovative Food 
Science and Emerging Technologies 8 (2): 306–315. 
 
Quinton, R. D., Cornforth, D. P., Hendricks, D. G., Brennand, C. P. and Su, Y. K. 
(1997). Acceptability and composition of some acidified meat and vegetable 
stick products. Journal Food Science.62:1250-1254. 
107 
 
 
Rahman, M. S., Guizani, N., Al-Ruzeiki, M. H. (2004). D and Z-values of microflora 
in tuna mince during moist- and dry-heating. Lebensm.-Wiss. U.-Technol.Food 
Science and Technology. 37: 93-98. 
 
Ranken, M. D. (2000). Handbook of Meat Product Technology. Blackwell Science 
Ltd., Oxford.pp29. 
 
Rao, M. V., Gault, N. F. S. and Kennedy, S. (1989). Variations in water holding 
capacity due to changes in the fibre diameter, sarcomere length and connective 
tissue morphology of some beef muscles under acidic conditions below the 
ultimate pH. Meat Science. 26: 19-37. 
 
Rawdkuen, S. and Benjakul, S. (2012). Biochemical and microstructural 
characteristics of meat samples treatedwith different plant proteases.A 
fricanJournal of Biotechnology. 11(76): 14088-14095. 
 
Rawdkuen, S., Pintathong, P., Chaiwut, P. and Benjakul, S. (2011).The partitioning of 
protease from Calotropis procera latex by aqueous two-phase systems and its 
hydrolytic pattern on muscle proteins. Food Bioproducts Processing. 89:73-
80.  
 
Ray, B. and B hunia, A. (2013).   Technology and Engineering. In: Fundamental Food 
th
Microbiology, 5   Edion. CRC Press. Boca Raton. London New York. pp256. 
 
Rich, L. M. and Foegeding, E. A. (2000). Effects of sugars on whey protein isolate 
gelation. Journal of Agricultural and Food Chemistry 48 (10): 5046-5052. 
 
Ricke, S. C. (2003). Perspectives on the use of organic acids and short chain fatty 
acids as antimicrobials. Poultry Science.82:632-639. 
 
Ritchey, S. J., and Hostetler, R. L. (1964). Relationships of free and bound water to 
subjective scores for juiciness and softness and to changes in weight and 
dimensions of steaks from two beef muscles during cooking.Journal of Food 
Science.29: 413-419. 
 
Robson, R. M., Huff-Lonergan, E., Parrish, Jr. F. C., Ho, C.Y., Stromer, M. H., 
Huiatt, T. W., Bellin, R. M. and Sernett, S. W. (1997). Postmortem changes in 
the myofibrillar and other cytoskeletal proteins in muscle. 50th Annual 
Reciprocal Meat Conference, Ames, Iowa, USA. American Meat Science 
Association. 50:43-52. 
 
Romans, J. R., Costelllo, W. J., Carlson, C. W., Greaser, M. L. and Jones, K. W. 
(1994). The Meat We Eat. Danville, I: Interstate, Inc. pp1193. 
 
Ruusunen, M. and Puolanne, E. (2005). Reducing sodium intake from meat 
products.Meat Science. 70(3): 531-541. 
 Sallam, Kh. I., Ishioroshi, M. and Samejima, K. (2004). Antioxidant and 
antimicrobial effects of garlic in chicken sausage. Lebensm.-Wiss. u.-
Technology. 37:849–855. 
108 
 
Samelis, J. and Sofos, J. (2003). Organic acids. In: Natural Antimicrobials for the 
Minimal Processing of Foods. (Editor. S. Roller), CRC Press, Florida.pp98–
132. 
 
Santchurn, S. J., Arnaud, E., Zakhia- Rozis, N. and Collignan, A. (2012). Handbook 
nd
of Meat and Meat Processing. Drying: Principles and Applications. 2  edition. 
pp 505. 
 
Sasse, A., Colindres, P. and Brewer, M. S. (2009). Effect of natural and synthetic 
antioxidants on oxidative stability of cooked, frozen pork patties. Journal of 
Food Science. 74: 30-35. 
 
Savell,  J. W., McKeith, F. K. and Smith, G. C. (1981). Reducing postmortem aging 
time of beef with electrical stimulation. Journal of Food Science,46:1777-
1781. 
 
Shackelford, S. D., Koohmaraie, M. and Wheeler, T. L. (1995). Effects of slaughter 
age on meat tenderness and USDA carcass maturity scores of beef. Journal of 
Animal Science.73: 3304-3309. 
 
Shackelford, S. D., Koohmaraie, M., Miller, M. F., Crouse, J. D. and Reagan, J. O. 
(1991). An evaluation of tenderness of the Longissimus muscle of angus by 
Hereford versus Brahman crossbred heifers. Journal of Animal Science. 69: 
171 – 177. 
 
Shacklelford, S. D., Koohmaraie, M., Cundiff, L. V., Gregory, K. E., Rohrer, G. A. 
and Savell, J. W. (1994). Heritability and phenotypic and genetic correlations 
for bovine postrigor calpastatin activity, intramuscular fat content, Warner- 
Bratzler shear force, retailproduct yield, and growth rate. Journal of Animal 
Science.72: 857-863. 
 
Shahidi, F. (1994). Assessment of lipid oxidation and off-flavor development in meat 
and meat products. In:Flavourof Meat and Meat Products. 1st 
edition.Chapman and Hall: London, U.K.pp 247 – 266. 
 
Sharma, B. D and Nanda, P. K. (2002). Studies on the development and storage 
stability of chicken chips. Indian Journal of Poultry Science.37: 155-158. 
 
Shiby, V .K., Tabassum, A., George, J., Pandey, M. C and Radhakrishna. K. (2015). 
Effect of drying methods on moisture sorption, microstructure and other 
quality characteristics of chicken cubes. International Journal of Advanced 
Research. 3(12):1200 – 1213. 
 
Shimokomaki, M., Franco, B. D. G. M., Biscontini, T. M., Pinto, M. F., Terra, N. N. 
and Zorn, T. M.T. (1998). Charqui meats are hurdle technology meat products. 
Food Review International. 14:339-349. 
 
Singh, V., Sanyal, M., Dubey, P. and Mendirtta, S. (2011). Quality assessment of 
vacuum packaged chicken snacks stored at room temperature. Journal of 
Stored Products and Postharvest Research. 2(6): 120-126. 
109 
 
th
Singleton, P. (1999). Bacteria in Biology, Biotechnology and Medicine. 5 edition. 
Wiley. Hoboken.pp. 444 – 454.  ISBN 0 – 471 – 98880 – 4. 
 
Smith, D. P., and Acton. J. C. (2001). Marination, cooking and curing of poultry 
products. In: Poultry meat science. (Editor. A. R. Sams) CRC Press, Boca 
Raton, FL pp 57 – 280. 
 
Smith, G. C. (1972). Relationship of the cow-calf producer to the consumer.In: 
Commercial beef cattle production. Lea and Febiger, Philadelphia, Pa. 
 
Smith, G. C., Carpenter, Z. L. Cross, H. R., Murphey, C. E., Abraham, H. C. Savell, J. 
W., Davis, G. W., Berry, B. W. and Parrish Jr, F. C. (1984). Relationship of 
USDA marbling groups to palatability of cooked beef. Journal Food Quality. 
7: 289-308. 
 
Smith, S. B. and Crouse, J. D.  (1984). Relative contributions of acetate, lactate and 
glucose to lipogenesis in bovine intramuscular and subcutaneous adipose 
tissue. Journal of Nutrition 114: 792-800. 
 
Smith, G. C., Pike, M. I. and Carpenter, Z. L. (1974). Comparison of the palatability 
of goat meat and meat from other animal species. Journal of Food Science. 
39:1145 – 1146. 
 
Smith, G. C., Tatum, J. D. and Belk, K. E. (2008). International perspective: 
characterisation of United States Department of Agriculture and Meat 
Standards Australia systems for assessing beef quality. Australian Journal of 
Experimental Agriculture, 48: 1465-1480. 
 
Sofos, J. N., Beuchat, L. R., Davidson, P. M. and Johnson, E. A. (1998). Naturally 
Occurring Antimicrobials in Food, Task force report No.132. Council for 
agricultural Science and Technology, Ames, IE pp103. 
 
Spielman, A. I. (1990).Interaction of saliva and taste. Journal of Dental Research.69: 
838-843. 
 
Stanton, C. and Light, L. (1989). The use of pre- rigor lactic acid injection to 
accelerate conditioning in bovine meat. Meat Science 27: 141 – 159. 
 
Stanton, C. and Light, N. (1990). The effects of conditioning on meat collagen: Part 
4—the use of pre-rigor lactic acid injection to accelerate conditioning in 
bovine meat. Meat Science. 27: 141–159. 
 
Sullivan, G. A. and Calkins, C. R. (2010). Application of exogenous enzymes to beef 
muscle of high and low-connective tissue. Meat Science. 85:730-734. 
 
Surimi and Surimi Seafood, (2013). 3rd Edion. (Editor. J. W. Park). Technology and 
Engineering CRC Press, Taylor and Francis Group. Boca Raton. London New 
York. pp376. 
 
110 
 
Sumner, J. and Jenson, I. (2011). The effect of storage temperature on shelf life of 
vacuum-packed lamb shoulders. Food Australia, 63:249–251. 
 
Tajkarimi, M. M., Ibrahim, S. A. and Cliver, D. O. (2010). Antimicrobial herb and 
spice compounds in food. Food Control. 21(9): 1199-1218. 
 
Takagi, H., Kondou, M., Hisatsuka, T., Nakamori, S., Tsai, Y. C. and Yamasaki, M. 
(1992). Effects of an alkaline elastase from an alkalophilic Bacillus strain on 
the tenderisation of beef meat. Journal of Agric Food Chemistry. 40:2364-
2368. 
 
Talib, M. A., Hassan, M. A., Bouba, A. I., Ngargueudedjim, K. (2014). 
Microbiological properties of cows meat dehydrated using solar drying, sun 
drying and oven drying. Journal of Medical and Biological Sciences. 3(3):1-4 
 
Tang, X. and Cronin, D. A. (2007). The effects of brined onion extracts on lipid 
oxidation and sensory quality in refrigerated cooked turkey breast rolls during 
storage. Food Chemistry. 100: 712–718. 
 
Taormina, P. J. (2010). Implications of salt and sodium reduction on microbial food 
safety. Critical Reviews in Food Science and Nutrition. 50 (3): 209-227. 
 
Tiwari, B. K., Valdramidis, V. P., O'Donnell, C. P., Muthukumarappan, K., Bourke, 
P. and Cullen, P. J. (2009). Application of natural antimicrobials for food 
preservation. Journal of Agricultural and Food Chemistry, 57: 5987-6000. 
 
Torres, E. A. F. S., Shimokomaki, M., Franco, B. D. G. M., Landgraf, M., Carbalho, 
B. C., and Santos, J. C. (1994). Parameters determining the quality ofcharqui, 
an intermediate moisture meat product.Meat Science. 38: 229-234.  
 
Townsend, W. E. and Olson, D. G. (1987). Cured and cured meat products 
processing. In: The Science of Meat and Meat Products, (Editors. J. F. Price. 
and B. S Schweigert).Food and Nutrition Press: Westport, Connecticut. pp 431 
– 456. 
 
Troller, J. A. (1976). Staphylococcal growth and enterotoxin production factors for 
control. Journal of Milk Food Technology.39: 499-503. 
 
USDA – FSIS, (2004). U.S. Department of Agriculture–Food Safety and Inspection 
Service (USDA-FSIS). Compliance guideline for meat and poultry jerky. 
USDA-FSIS, Washington, D.C. Available at: 
http://www.fsis.usda.gove/OPPDE/nis/outreach/models/Jerkyguidelines.htm. 
 
USDA – FSIS, (2005). U.S. Department of Agriculture, Food Safety and Inspection 
Service. 2005. Food standards and labeling policy book. Available at: 
http://www.fsis.usda.gov/OPPDE/larc/Policies/Labeling_Policy_Book_08200
5.pdf. 
 
111 
 
Wada, M., Suzuki, T., Yaguti, Y. and Hasegawa, T. (2002). The effect of pressure 
treatments with kiwi fruit protease on adult cattle Semitendinosus muscle. 
Food Chemistry. 78:167-171. 
 
Weir, C. E. (1960). Palatability characteristics of meat. In:The Science of Meat and 
Meat Products. W. H. Freeman and Company, San Francisco, Calif. pp 156. 
 
Wenham, L.  M. and Locker, R.  H. (1976).The effect of marinade on beef. Journal of  
Science of Food and Agriculture. 27:1079-1084. 
 
Wentworth, E. N. (1956). Dried meat: Early man's travel ration. Agricultural History. 
30: 2- 10 
 
Wheeler, T. L., Cundiff, L. V., Shackelford, S. D. and Koohmaraie, M. (2004). 
Characterisation of biological types of cattle (Cycle VI): Carcass, yield and 
longissimus palatability traits.Journal of Animal Science. 82(4):1177-1189. 
 
Wheeler, T. L., Koohmaraie, M., Lansdell, J. L., Siragusa, G. R., and Miller, M. F. 
(1993). Effects of postmortem injection time, injection level, and 
concentration of calcium chloride on beef quality traits. Journal of Animal 
Science. 71: 2965-2974. 
 
Wheeler, T. L., Shackelford S. D., Koohmaraie, M. (1996).Sampling, cooking, and 
coring effects on Warner-Bratzlershear force values in beef. Journal of Animal 
Science. 74:1553–1562. 
 
Wijayawardana, K. H. R.., Cyril1, H. W. and Fonseka, T. S. G. (2001).Effect of 
different marinades on the tenderness of beef. Tropical Agricultural Research.  
13:61-68. 
 
Wilson, N. R. P. Dyertt, E. J., Hughes, B. R., Jones, C. R. V. (1981). Meat and meat 
th
products. In: Factors affecting quality control. 5 edition, pp 81 – 108. 
(Applied Science: London).  
 
Wongwiwat, P. and Wattanachant, S. (2014). Effect of sugar types on physical 
attributes and crystalline structure of sweet dried chicken meat products. 
International Journal of food research.12 (6):2285 – 2291.  
 
Xargayo, M., Lagares, J., Fernández, E., Ruiz, D., Borrell, D. (2001). Marination of 
fresh meat by means of spray effect: Influence of spray injection on the quality 
of marinated products. Fleischwirstschaft. 70-74 
 
Xiao, S., Zhang, W., Lee, E., Ma, C. and Ahn, D. (2011). Lipid and protein oxidation 
of chicken breast rolls as affected by dietary oxidation levels and packaging 
Journal of Food Science. 76(4) C612-C617. 
 
Xiong, Y. L. and Kupski, D. R. (1999). Time-dependent marinade absorption and 
retention, cooking yield and palatability of chicken fillets marinated with 
various phosphate solutions. Poultry Science 78:1053-1059. 
 
112 
 
Yang, H. S., Hwang, Y. H., Joo, S. T. and Park. G. B. (2009).The physicochemical 
and microbiological characteristics of pork jerky in comparison to beef jerky. 
Meat Science. 82:289-294.  
 
Yang, S. H., Lee, E. J., Moon, S. H., Paik, H. D., Nam, K. and Ahn, D. U. (2011). 
Effect of garlic, onion, and their combination on the quality and sensory 
characteristics of irradiated raw ground beef. Meat Science. 89(2):202 – 208. 
 
Yoon, Y., Skandamis, P. N. and Kendall, P. A. (2006). A predictive model for the 
effect of temperature and predrying treatments in reducing Listeria 
monocytogenes populations during drying of beef jerky. Journal of Food 
Protection. 69(1): 62-70. 
 
Young, J. E. and Yang, R. (1975). Studies on the ageing of bovine muscle on adding 
proteolytic enzyme. V. studies on the tenderness evaluation of bovine muscle 
treated with papain by using penetration value. Korea Journal of Food Science 
and Technolog.7:208. 
 
Zhou, G.H., Xu, X. L.  and Liu, Y. (2010).A review: Preservation technologies for 
fresh meat. Meat Science 86(210)119-128.  
 
 
 
 
 
 
 
 
 
 
 
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