Research on pasteurization and packaging methods to prolong the shelf life of tofu

THAI NGUYEN UNIVERSITY OF AGRICULTURE AND FORESTRY MA MICHELLE R DELA ROSA RESEARCH ON PASTEURIZATION AND PACKAGING METHODS TO PROLONG THE SHELF-LIFE OF TOFU BACHELOR THESIS Study mode Major Faculty Batch : Full time : Food Technology : Advanced Education Program : 2018-2022 Thai Nguyen 2022 i ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of Food Technology Student name Ma Michelle R Dela Rosa Student ID DTN1754190024 Thesis Title Research on Pasteurization and Packaging Methods to Prolong the Shelf-life of Tofu Supervisor (s) Dr Lương Hùng Tiến Co-Supervisor Dr Condro Wibowo Supervisor’s Signature Abstract: Tofu is a nutritive food that could contribute to fulfil protein requirement for people in a remote location However, it is also an ideal medium for microbes to multiply due to its nutrients and wet environment This study was conducted to evaluate pasteurization modes and packaging methods and materials to extend the shelf life of the tofu IBM SPSS was used in analyzing the gathered data in best pasteurization time and temperature applying two treatments in packaging The result showed that 90℃ pasteurization temperature and 5-minute pasteurization time and applied in PP tray packaging is the most optimal method to prolong the shelf-life of tofu up to 24 days The pH is 5.50, protein is 11.26%, acid is 0.59%, ash is 0.57g, total microbial is 0.27.103 cell/g, yeast and mold is 0.93103 cell/g, E coli is none and sensory quality score is 19.03±0.35 Keywords: packaging, pasteurization, soy beans, tofu, shelf-life Number of pages: 36 Date of Submission: June 1st, 2022 i ACKNOWLEDGMENT I would like to express my deepest gratitude to my family who continuously supports and understands me throughout my research, and to my supervisors, Dr Lương Hùng Tiến and Dr Condro Wibowo, whose always in my side encouraging, guiding, imparting valuable knowledge, checking everything is in good condition amid pandemic and who made this research possible and Ms Pham Thi Phuong and MSc Nguyễn Thương Tuấn for being patient with me, helped, guided, and shared their knowledge I would also like to give my gratitude to my classmates and fellow Filipinos for making my thesis in Vietnam more enjoyable and enthusiastic to Constantly encouraged and gave me their unending support during hard times and also in my last period of study in Vietnam I also would like to express my deepest gratitude to Thai Nguyen University of Agriculture and Forestry, Faculty of Biotechnology and Food Technology, and the Advanced Program Office for creating a convenient place to study and making my thesis feasible I also like to convey my sincere thanks to the school management board, the Dean of the Faculty and the collective of teachers in the Faculty of Biotechnology and Food Technology, Thai Nguyen University of Agriculture and Forestry for helping me in any possible they can Finally, I would like to thank God for all the hardships and difficulties that I encountered and was able to accomplish The guidance that God has given me every step of the way of the process His greatness and steadfast love showered me throughout the construction of my thesis that made my research successfully finished Finally, I would like to thank God for all the hardships and difficulties that I encountered and was able to accomplish The guidance that God has given me every step of the way of the process His greatness and steadfast love showered me throughout the construction of my thesis that made my research successfully finished Thank you sincerely! Thai Nguyen, May, 2nd ,2022 Sincerely MA MICHELLE R DELA ROSA ii TABLE OF CONTENTS UNIVERSITY OF AGRICULTURE AND FORESTRY i ABSTRACT i ACKNOWLEDGMENT ii LIST OF FIGURES v LIST OF TABLES vi LIST OF ABBREVIATIONS vii CHAPTER I INTRODUCTION 1.1 Research nationale 1.2 Research’s objective 1.3 Research Question and Hypothesis 1.4 Limitations 1.5 Significance of the Study CHAPTER II LITERATURE REVIEW 2.1 Overview of tofu 2.4 Soybean Production in Vietnam 2.5 Pasteurization 2.6 Packaging 10 2.6.1 Polypropylene Tray (PP Tray) 11 2.6.2 Polyethylene Terephthalate (PET) 12 2.6.3 Nylon Bag 12 2.6.4 Polyethylene (PE) 12 2.6.5 Low-Density Polyethylene (LDPE) 13 CHAPTER III 14 3.1 Materials and research scope 14 3.5.2.4 Determination of Acid Content 18 3.5.2.5 Total Microbiological Determination Method 18 3.5.2.6 Method of determining Yeast - Mold 19 3.5.2.7 Method of determining coliform method MPN 20 3.5.2.8 Sensory Evaluation 20 iii CHAPTER IV 24 RESULT AND DISCUSSION 24 CONCLUSION AND RECOMMENDATION 33 REFERENCES 34 APPENDIX 38 iv LIST OF FIGURES 2.1 Tofu production process……………………………………………….……… Error! Bookmark not defined v LIST OF TABLES Table 2.1 Soybean production in Vietnam from 2018 to 2022….…………… Table 2.3.1 Experiment chemicals…………………………….…………….……… 15 Table 3.2 Laboratory instruments ……………… ………………………….……… 16 Table 3.3 Experimental equipment …… …………………………………… …… 17 Table 3.5.2 Culture medium (YGC: Yeast – Glucose –Chloramphenicol) .…… 20 Table 3.5.3 Culture medium (TGA: Triptone – Glucose –Agar)……… ………… 21 Table 3.5.4 Endo-environment ……………………………… ……………… 22 Table 3.5.5 Sensory quality score…………………………… ………….………….22 Table 3.5.6 Quality level specified standard…………………… ……………… 23 Table 4.1.1 Effect of pasteurization temperature on pH content……………… … 25 Table 4.1.2 Effect of pasteurization temperature on protein content……………… 25 Table 4.1.3 Effect of pasteurization temperature on acid content…….…………… 26 Table 4.1.4 Effect of pasteurization temperature on total microorganism content …27 Table 4.1.5 Effect of pasteurization temperature on total yeast and mold content….27 Table 4.1.8 Effect of pasteurization temperature on sensory quality……………… 28 Table 4.2.1 Effect of pasteurization time on pH content ……………………… ….29 Table 4.2.2 Effect of pasteurization time on protein content ……………………….29 Table 4.1.3 Effect of pasteurization time on acid content ……… .…………… 29 Table 4.2.3 Effect of pasteurization time on total microorganism content …………30 Table 4.2.4 Effect of pasteurization time on yeast and mold content ….………… 30 Table 4.3.1 Effect of combination of treatments in different packaging on pH content ………………………………………………………………………………………32 Table 4.3.2 Effect of combination of treatments in different packaging on protein content………………………………………………………………………………32 Table 4.3.3 Effect of combination of treatments in different packaging on acidity content ………………………………………………………………………… ….33 Table 4.3.5 Effect of combination of treatments in different packaging on total microbial content ……………………………………………………………… …33 Table 4.3.6 Effect of combination of treatments in different packaging on total microbial content ……………………………………………………………… …34 Table 4.3.8 Sensory Evaluation of Tofu in Combination of Treatments in Different Packaging …………………………………………………………………… …35 vi LIST OF ABBREVIATIONS AOAC Association of Official Agricultural Chemists DOST Department of Science and Technology E coli Escherichia coli FDA Food and Drug Administration GWP Global Warming Potential LDPE Low-Density Polyethylene MPN Most probable number PE Polyethylene PET Polyethylene Terephthalate PPT Polypropylene Tray USDA United State Department of Agriculture vii CHAPTER I INTRODUCTION 1.1 Research nationale Soybean (Glycine Max) is one of the highly utilized agricultural products in many countries because it contains essential amino acids and can be processed into various types of products Soybean has an abundant amount of protein content and is found that it is anticarcinogenic, lowers blood cholesterol and sugar, and osteoporosis (Anbarasu & Vijayalakshmi, 2007) Food products produced from soybean are soy milk, tofu, miso, soy sauce, tempeh, natto and so much more usage of soybean is more popular in Asia cuisine but it also gains popularity in western countries as it is good for the health (Pre'stamo et al., 2000) Tofu is a wide source of everyday diet especially, in Asian countries topped up with a good price and the quality of the food makes it answer poverty in some countries It is non-fermented from soybean curd It can be used as a substitute for meat for people who are vegetarian and have some health issues The gelation of soybeans is similar to cheese-making (Pre'stamo et al., 2000) Tofu has entitled "bland white cake in water" which grasp the attention of western people also a commune in Tennesse is one of the reasons why tofu is recognized and widely accepted in many countries due to the first-ever ice-cream without dairy product called Tofutti ice cream (Nguyen, 2012) Inadequate sanitary measures in the tofu manufacturing process may lead to the purchase and consumption of unfit tofu products The analysis of tofu contamination rates and types of contaminating bacteria could provide useful information for tracing the source of bacterial contamination and developing appropriate food hygiene procedures for tofu manufacturing (Ananchaipattana et al., 2012) A study conducted by Ananchaipattana et al., (2012) stated that tofu samples in packed and unpacked tofu found that spoilage bacteria are found in the unpacked tofu due to exposure to the external environment which can cause easily deteriorate and unsafe for human consumption, therefore, packed tofu lengthen the shelf life and safe for consumers In this research, an attempt is made to develop pasteurization formulations and packaging methods to extend the shelf life of tofu for better product delivery and consumer convenience Moreover, this study also evaluated the effects of pasteurization temperature, pasteurization time, and packaging materials on the nutritional and sensory value of tofu products This study will provide additional useful data for the food science community and serve as a reference source for further studies 1.2 Research’s objective The general objective of this study is to evaluate pasteurization modes and packaging materials to extend shelf life of the tofu - Determine the effect of pasteurization temperature on the quality and shelf life of tofu - Determine the effect of pasteurization time on the quality and shelf life of tofu - Determine the effect of packaging conditions on the quality and shelf life of tofu 1.3 Research Question and Hypothesis In order to answer the purpose of this research, the main research question which will be investigated during the research process is: Do the pasteurization modes affect shelf-life of tofu? Do packaging materials and methods affect shelf-life of tofu? How does the combination of treatments affect tofu storage time under different conditions? 1.4 Limitations - Pasteurization at High-temperature is the main cause of protein denaturation, reducing fat, and volatile compounds that reduce the quality of tofu Tofu is usually firmer and less smelly after pasteurization 1.5 Significance of the Study - The result of the study will provide information for product development in the food industry - The outcome of the research will serve as a resource base to other scholars and researchers interested in carrying out further research in this field subsequently CHAPTER IV RESULT AND DISCUSSION 4.1 The effect of pasteurization temperature on tofu quality and storage time Table 4.1 Effect of pasteurization temperature on pH content Pasteurization days days days 12 days 15 days 70℃ 6.08a 5.60a 5.41a 5.33a 5.16a 75℃ 6.04a 5.67a 5.37a 5.38a 5.21a 80℃ 6.14a 5.66a 5.39a 5.37ab 5.27ab 85℃ 6.17a 5.76a 5.59b 5.46bc 5.31b 90℃ 6.27b 5.85b 5.74b 5.49c 5.38b temperature Note: the letters in the same column represent the statistically significant difference at the a