The Impact of Ingredient Formulation and Processing Parameters on Colour and Texture of Instant Noodles A thesis submitted in fulfillment of the requirements for the degree of Doctor of Philosophy Cecillia Widjaya B.Sc. Food Science and Technology (Hons) RMIT University School of Applied Sciences Science, Engineering and Technology Portfolio RMIT University July 2010 Declaration I certify that except where due acknowledgement has been made, the work is that of the author alone; the work has not been submitted previously, in whole or in part, to qualify for any other academic award; the content of the thesis 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. Cecillia Widjaya July 2010 i Acknowledgements Acknowledgments I express my greatest appreciation firstly to my supervisor, Associate Professor Darryl Small for his guidance and encouragement. His advices and support throughout my study as well as outside university are greatly appreciated. To my co-supervisor, Dr Larisa Cato (Department of Agriculture and Food, W. A., Perth) I gratefully thank her in sharing her expertise in noodle products, and her feedback, discussions, prompt replies and support are greatly appreciated. I sincerely thank Dr Ali Jafarpour for providing his invaluable knowledge in the use of the texture analyser and to Dr Tatdao Paseephol for her help and advice on the use and interpretation of statistical analyses as well as more generally on my project. I also greatly appreciate Mr Philip Francis (Manager, Electron Microscopy) for providing his proficiency on the environmental scanning electron microscope and to Dr Jeffrey Hughes for helpful discussions on statistical analyses. Thanks are also due to many people in the RMIT University city campus, to the pilot plant staff of the School of Applied Sciences; Michael Kakoullis (Laboratory Manager), Lillian Chuang and Mary Pecar (Technical Officers), to the Applied Chemistry staff; Karl Lang (Laboratory Manager), Zahra Homan and Dianne Mileo (Technical Officers), and to the Laboratory Technicians, Nadia Zakhartchouk and Ruth Cepriano-Hall for their assistance with the resources and facilities I needed for my project as well as wonderful service and friendship. Special thanks to Kaarina Liind (Academic Services Coordinator) and Professor Ann Lawrie for their immense support in administration related issues. I also thank my colleagues, Marissa Wijaya, Elis, Nicha Kawila, Ai Ling Choy, Mohamed Ahmed Omer, Dr Rodney Hau and Dr Lan Bui for their warm friendship. I express my sincere appreciation for the financial support provided by the Commonwealth Operating Grant throughout the course of the study as well as the assistance received to support my participation and presentations at various conferences. In particular, I thank the Royal Australian Chemical Institute, Cereal Chemistry ii Acknowledgements Division for an award supporting me to attend the 58th Australian Cereal Chemistry Conference during September 2008 in Surfers Paradise. Last but not least, my greatest gratitude is due to my family for their financial and moral support, love and encouragement. Finally, I am very honoured to have worked with Darryl and Larisa. I valued their enthusiasm, commitment and continuous support in providing me with valuable opportunities and experiences. It is also a privilege to have been acquainted with the people from the School of Applied Sciences in RMIT University. iii Publications Publications and presentations Various parts of the research reported in this thesis have been published and the details are as follows: Refereed conference proceedings papers Widjaya, C.A., Cato, L. and Small, D.M. (2007) Factors influencing the textural characteristics of Asian instant noodles, published in: Panozzo, J.F. and Black, C.K. (Eds), Cereals 2007 – Proceedings of the 57th Australian Cereal Chemistry Conference ‘The Appliance of Science’. Held from the 5th until the 9th of August 2007 in Melbourne. Australia and published by the Royal Australian Chemical Institute, Melbourne, ISBN 1 876892 16 3, pp 206-209. Widjaya, C.A., Cato, L. and Small, D.M. (2008) A study of fungal lipase and alkaline salts on the quality of instant Asian style noodles, published in: Panozzo, J.F. and Black, C.K. (Eds), Cereals 2008 – Proceedings of the 58th Australian Cereal Chemistry Conference, held from 31st August-4th September 2008, Surfers Paradise, Gold Coast, Queensland, Australia and published by the AACC DownUnder Section, North Ryde, NSW, ISBN 1 876892 18 1, pp 137-140. Other conference presentations Widjaya, C. A., Cato, L. and Small, D. M. 2006. An environmental scanning electron microscope study of commercial instant noodle products. Paper presented at the 56th Australian Cereal Chemistry Conference, ‘Indian Ocean Rim – Growth and Innovation’. Held from 10-14 Sept 2006 in Fremantle, Perth, Australia. Widjaya, C.A., Cato, L. and Small, D.M. (2006) The removal of fat and the impact on the interactions of other components in foods, Paper presented at the 14th Annual RACI Analytical and Environmental Divisions R and D Topics, Wollongong, 5th- 8th December. Widjaya, C.A., Cato, L. and Small, D.M. (2007) A study of sample alignment and presentation during the instrumental assessment of textural characteristics of Asian instant noodles. Paper presented at the 40th Anniversary AIFST Convention, Melbourne, 24th-27th June. Widjaya, C.A., Cato, L. and Small, D.M. (2007) The impact of fat and protein content on the textural characteristics of Asian instant noodles. Paper presented at the 40th Anniversary AIFST Convention, Melbourne, 24th-27th June. Widjaya, C.A., Small, D.M. and Cato, L. (2008) Optimisation of parameters influencing the characteristics of Asian instant noodles. Paper presented within the Technical Session “Processing of Cereal Grains and Grain Products” at the 13th ICC Cereal and Bread Congress - Cerworld 21st “Cereals worldwide in the 21st century: present and future”, Madrid, Spain 15th-18th June 2008. iv Publications Chow, M. M., Widjaya, C. A. and Small, D.M. 2008. Quality of Asian instant noodles influenced by salt and alkaline salts. Paper presented at the 58th Australian Cereal Chemistry Conference, held from 31st August-4th September 2008, Surfers Paradise, Gold Coast, Queensland, Australia Widjaya, C.A., Cato, L. and Small, D.M. (2008) Instant noodles: the impact of processing variables on the quality attributes. Paper presented at the Annual Meeting of the American Association of Cereal Chemists International, September 21-24, 2008, Honolulu, Hawaii. Widjaya, C.A., Choy, A. L., Hughes, J. G. and Small, D.M. (2008) Processing and ingredient effects on the quality of instant Asian noodles. Paper presented at the 14th World Congress of Food Science and Technology, 19 - 23 October 2008, Shianghai, China. v Abstract Abstract Wheat based products are a major food source worldwide, with wheat covering more land area for cultivation than any other crop. Wheat represents over 30% of global cereal production and noodles are one of the popular end products that are a staple food in many countries especially in Asia. Here 30 - 40% of wheat flour is used for making variety of noodles which vary in ingredients, process and shape of the finished products according to regional preferences. Whilst there has been considerable research into the traditional styles, yellow alkaline and white salted noodles, relatively few studies have focused on instant noodles. Therefore the aim of this study was to advance our knowledge on the quality of Asian instant noodles, by specifically investigating and optimising ingredient formulation and processing variables. In addition, the potential for enhancing quality by incorporation of a commercial lipase preparation has been evaluated. Noodle samples were made on a laboratory scale and characteristics evaluated included appearance (colour, uniformity and speckiness), microstructure, texture, fat and moisture uptake as well as the cooking properties. The experimental approach was carried out according to response surface methodology following second order central composite face centered design. Within these trials, generally 13 randomly selected combinations including 5 centre points were evaluated. Initial studies were performed on the validation of procedures including those for the texture analyser and fat extraction, in order to ensure the use of the most effective and reliable procedure in measuring the quality of the samples. A variety of commercial instant noodles from different manufacturers was then evaluated and significant variation in colour, textural attributes and structural attributes was found. These results indicated the possibility that different ingredients, formulation as well as manufacturing procedures impacted on the differences in the characteristics of the final product. The relationship between fat and protein content as well as the texture and microstructure of instant noodles was also investigated. The results showed that fat does not influence the appearance of either the surface or the cross sectional area of instant noodles. However, fat content is negatively correlated with the protein content of flour and the hardness of cooked noodles. vi Abstract A major focus of the project involved a series of trials investigating the impact of processing procedures for Asian