Reham Mohamed Mohamed Abd El-kader PDF
Preview Reham Mohamed Mohamed Abd El-kader
Faculty of Science Microbiology department “ Development of safe juices for immunocompromised patients by irradiation alone or in combination with other technologies” By Reham Mohamed Mohamed Abd El-kader B. Sc. Microbiology – Biochemistry (2007) Faculty of Science, Ain- shams University National Center For Radiation Research and Technology Thesis submitted in partial fulfillment of the requirement for M. Sc. Degree in Microbiology Microbiology Department Faculty of Science Ain-Shams University 2012 Faculty of Science Microbiology department “Development of safe juices for immunocompromised patients by irradiation alone or in combination with other technologies” By Reham Mohamed Mohamed Abd El-Kader B. Sc. Microbiology - Biochemistry (2007) National Center For Radiation Research and Technology Supervised by: Prof. Khayria Abd El-Ghany Youssef Professor of Microbiology, Faculty of Science, Ain Shams University Prof. Ali Ahmed Ibrahim Hammad Professor of Food Science and Microbiology, Former Vice Chairman of Egyptian Atomic Energy Authority Dr. Hanan Hassan Abd El-Khalek Lecturer of Microbiology, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority 2012 Faculty of Science Microbiology department Name: Reham Mohamed Mohamed Abd El-Kader Title: “Development of safe juices for immunocompromised patients by irradiation alone or in combination with other technologies” Supervised by: 1-Prof. Khayria Abd El-Ghany Youssef…………… Professor of Microbiology, Faculty of Science, Ain Shams University. 2-Prof. Ali Ahmed Ibrahim Hammad…………….. Professor of Food Science and Microbiology, Former Vice Chairman of Egyptian Atomic Energy Authority. 3- Dr. Hanan Hassan Abd El-Khalek……………. Lecturer of Microbiology, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority(AEA). Faculty of Science Microbiology department “Development of safe juices for immunocompromised patients by irradiation alone or in combination with other technologies” By Reham Mohamed Mohamed Abd El-Kader B. Sc. Microbiology - Biochemistry (2007) National Center For Radiation Research and Technology Approved by: 1-Prof. Mohie Eddin Zohier El-Fouly Professor of Microbiology, National Center For Radiation Research and Technology ( NCRRT ), Atomic Energy Authority 2-Prof. Mohamed Ghareeb Ibrahim Emaish Professor of Microbiology, Faculty of Education, Ain Shams University. 3-Prof. Khayria Abd El-Ghany Youssef Professor of Microbiology, Faculty of Science, Ain Shams University 4-Prof. Ali Ahmed Ibrahim Hammad Professor of Food Science and Microbiology, Former Vice Chairman of Egyptian Atomic Energy Authority DEDICATION To my mum Mrs.Nawal Mahmoud. Your constant motivation and faith has always given me hope. Now, this is was your dream, through me. Thank You. & To my brother Islam Abdelkader for his supports and encouragements. D & To my father soul, God bless him. Finally, this thesis is dedicated to all those who believe in the richness of learning. ACKNOWLEDGEMENTS All praises and thanks are for ALLAH who is the entire source of all knowledge and wisdom endowed to mankind Prof. Khayria Abd El-Ghany Youssef, thank you for believing in me; for your encouragement through kind words, support, your guidance, for effective and helpful supervision, Fruitful discussion and valuable advice. Prof. Ali Ahmed Ibrahim Hammad, thank you for suggestion of the point, assigning the work, kindly supplied me with all necessary facilities, carefully editing this thesis and your attention to finer details, and thanks for your encouragement, guidance, patience, time and expertise on this work. My heartfelt gratitude goes to Dr. Hanan Hassan Abd El-Khalek for all her help, encouragement and dedication in helping me, support, patience, and sincere advices, advance my knowledge and making this work possible. Prof Hussein Abd El-Kareem Head of Microbiology department, National Center for Radiation Research and Technology (NCRRT).Atomic Energy Authority(AEA).A cooperative and affectionate personality, special thanks are extended to you for the care, impetus and encouragements. Thanks to the head of Microbiology department Mohamed khaled Ibrahim and to the faculty, staff and members of the Microbiology department for their help and their academic advice. My deepest graditude to all staff of Microbiology department, National Center for Radiation Research and Technology for their friendship and their advice. Last, but not least my deep thanks are extended to my family and all my friends, their love, understanding and unfailing support has made everything possible. I thank all those who, in different ways, have walked beside me along the way; offering support and encouragement, challenging my thinking, and teaching me to consider alternative views. Name : Reham Mohamed Mohamed Abd El-Kader Title of Thesis : Development of safe juices for immunocompromised patients by irradiation alone or in combination with other technologies. Degree: M.Sc. Faculty : Science University : Ain Shams Department : Microbiology Abstract Fresh fruit and vegetable juices have become a new functional food available for dietary and health. However, they have high microbial load and poses a microbial hazard to consumer unless treated with a suitable method of food preservation. Gamma irradiation, as non thermal process, is highly effective in destruction of both spoilage and pathogenic microorganism in various foods without arising its temperature, hence keeping its freshness and nutritional quality. In recent years, it is used as a safe and alternative method for food preservation in many countries. In present study, pomegranate, tomato and carrot juices were irradiated at different irradiation doses (1- 4.5 kGy). Yeasts, as the principle cause of juices spoilage, were isolated and identified from unirradiated (control) juices. The resistance of the identified yeasts to gamma radiation in the term of D - value was 10 investigated. It was found that Debaryomyces hansenii had the highest radiation resistance ( D -value of 1.63 kGy ) while Candida tropicalis had the lowest 10 resistance to gamma radiation ( D -value of 0.98 kGy ).The effect of these 10 irradiation doses on the microbiological load, nutritional, physiochemical and sensory properties were evaluated immediately after irradiation and during subsequent refrigeration storage. Generally, irradiation doses of 1.0 kGy and above were efficient and sufficient for complete elimination of coliform bacteria and E.coli found in these juices without impairing the nutritional and sensory quality attributes. Irradiation of pomegranate juice at 2.5 kGy greatly reduced its microbial counts and extended the shelf-life to 14 days at refrigeration temperature (4°C±1) with minimal changes in the anthocyanin content. Irradiation dose of 3.0 kGy could improve the microbial quality, ensure safety and extend the shelf-life of tomato juice to 15 days at refrigeration temperature without significant changes in lycopoene content. Meanwhile, irradiation dose of 3.0 kGy in combination with cinnamaldehyde (8µl/100 ml) greatly reduced the microbial load of carrot juice and extended its shelf-life to 21 days at 4°C±1 without adverse effect on the sensory and nutritional quality. Key words : pomegranate juice, tomato juice, carrot juice, irradiation, nutritional quality.
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