Application of Olive Leaf Extract and
Chitosan As Natural Preservatives for Beef
Patties
A thesis submitted in fulfilment of the requirements for the degree of Master of Science
Nidhi Jindal
B.Sc. (Biotechnology) (Himachal Pradesh University, India)
M.Sc. (Biotechnology) (Dr YS Parmar University of Horticulture and Forestry, India)
School of Science
(College of Science, Technology, Engineering and Maths)
RMIT University
August 2022
i
Declaration
I certify that except where due acknowledgement has been made, this research is that of the
author alone; the content of this research submission is the result of work which has been carried
out since the official commencement date of the approved research program; any editorial work,
paid or unpaid, carried out by a third party is acknowledged; and, ethics procedures and
guidelines have been followed.
In addition, I certify that this submission contains no material previously submitted for award of
any qualification at any other university or institution, unless approved for a joint-award with
another institution, and acknowledge that no part of this work will, in the future, be used in a
submission in my name, for any other qualification in any university or other tertiary institution
without the prior approval of the University, and where applicable, any partner institution
responsible for the joint-award of this degree.
I acknowledge that copyright of any published works contained within this thesis resides with
the copyright holder(s) of those works.
I give permission for the digital version of my research submission to be made available on the
web, via the University’s digital research repository, unless permission has been granted by the
University to restrict access for a period of time.
I acknowledge the support I have received for my research through the provision of an Australian
Government Research Training Program Scholarship.
Nidhi Jindal
29.08.2022
ii
Acknowledgement
Firstly, I would like to thank my Supervisors Professor Benu Adhikari and Associate Professor
Peter Torley for their guidance, valuable feedback and providing me with cordial scholarly
environment to undertake my research. I would also thank Dr Mandeep Kaur for her guidance
and support. I would also like to acknowledge Australian Meat Processor Corporation (AMPC)
for providing me with scholarship which enabled me to undertake this study.
I express my gratitude to the technical staff of RMIT University (Mina Dokouhaki, Lillian
Chuang, Yan Chen, Sanaz, Sahlehi, James Lauer, Hadi Ranjiburachaloo, Jake Torrisi, Spiros
Tsaroumis) for technical support. I am thankful to my laboratory colleagues Nelum Pematilleke,
Michelle Xu, Mehran Ghasemlou, Bao Loc Pham, Billy Lo, Pranita Mahske for their support
and friendship.
Last but not least, I would like to thank my loving husband for being my strength and for his
immense support and encouragement that helped me achieve my goal. I would like to thank my
little son whose smile always takes away all the stress during a challenging time. I am grateful
to my mum, whose words of encouragement helped me to stay motivated all the time and to my
brother for his love and support.
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Table of contents
Declaration……………………………………………………………………………………….i
Acknowledgement……………………………………………………………………………....ii
Table of contents………………………………………………………………………………..iii
List of figures…………………………………………………………………………………...vi
List of tables……………………………………………………………………………….......viii
List of abbreviations…………………………………………………………………………….X
Abstract………………………………………………………………………………………….1
CHAPTER 1 INTRODUCTION………………………………………………………………4
1.1 Background……………………………………………………………………………….....5
1.2 Expected outcomes………………………………………………………………………….6
1.3 Research questions and objectives………………………………………………………......7
1.4 Outline of thesis……………………………………………………………………………..7
References…………………………………………………………………………………...9
CHAPTER 2 LITERATURE REVIEW……………………………….................................11
2.1 Introduction………………………………………………………………………………..12
2.2 Meat packaging……………………………………………………………………………12
2.2.1 Overwrap aerobic packaging………………………………………………………….13
2.2.2 Modified atmosphere packaging………………………………………………………13
2.2.3 Vacuum packaging……………………………………………………………………14
2.3 Meat quality attributes effected by oxygen inside the meat packages…………………….14
2.3.1 Oxidative stability……………………………………………………………………..15
2.3.1.1 Meat colour and its stability……………………………………………………....16
2.3.1.2 Meat lipid and its stability………………………………………………….……..17
2.3.1.3 Meat protein and its stability………………………………………………….…..18
2.3.2 Impact on microbial growth………………………………………………………….19
2.4 Natural additives for reducing detrimental effect of oxygen on meat quality attributes...19
2.4.1 Application of antioxidants for extension of shelf life of meat …………………..…19
2.4.2 Application of antimicrobials for extension of shelf life of meat……………………24
2.4.3 Antioxidant and antimicrobial combinations………………………………………...27
2.5 Concluding remarks………………………………………………………………….......28
References……………………………………………………………………………..28
iv
CHAPTER 3 MATERIALS AND METHODS…………………………………………......38
3.1 Beef samples and Chemicals………………………………………………………….……39
3.2 Determining the combined effect of olive leaf extract and chitosan on the physiochemical
attributes of beef patties stored under high oxygen packaging conditions………………...39
3.2.1 Preparation, packaging and storage of beef patties…………………………………....39
3.2.2 Determination of antioxidant activity of olive leaf extract……………………………42
3.3.3 Determination of surface colour of beef patties ………………………………………42
3.2.4 Determination of metmyoglobin and oxymyoglobin contents in beef patties………...42
3.2.5 Determination of lipid oxidation in patties……………………………………………43
3.3 Determining combined effect of olive leaf extract and chitosan on the microbial shelf life
of beef patties stored under high oxygen packaging conditions………………………....44
3.3.1 Preparation, packaging and storage of beef patties…………………………………...44
3.3.2 Determination of pH and headspace gas composition of packaging…………,,……..44
3.3.3 Determination of total viable counts and lactic acid bacterial counts in patties……….44
3.3.4 Experimental design and statistical analysis……………………………………….….45
References………………………………………………………………….………....45
CHAPTER 4 COMBINED EFFECT OF OLIVE LEAF EXTRACT AND CHITOSAN
ON THE PHYSIOCHEMICAL ATTRIBUTES OF BEEF PATTIES STORED
UNDER HIGH OXYGEN PACKAGING ATMOSPHERE..............................................47
4.1 Introduction………………………………………………………………………….........48
4.2 Materials and Methods………………………………………………………………........50
4.3 Results and discussion…………………………………………………...………….........50
4.3.1 Antioxidant activity of olive leaf extract…………………………………………...….50
4.3.2 Change in surface colour in patties……………………………………………….........51
4.3.3 The state of myoglobin in patties……………………………………………………...54
4.3.4 Lipid oxidation in patties……………………………………………………………...56
4.3.5 Correlations among beef patties quality parameters…………………………………...58
4.4 Conclusion………………………………………………………………………………...59
References…………………………………………………………………………….......60
Supplementary material………………………………………………………………...…64