A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 2000

Cassava is grown in a number of developing tropical countries and represents one of the worlds most important food sources providing for millions of people. Thailand is one of the worlds largest producers of cassava and is by far the biggest exporter of cassava starch, exporting more than 75% of the total cassava starch exported in the world. However, with the large decrease in the market for cassava chips and pellets for animal feed, alternative uses of cassava is a major focus of research. Similarly the utilisation of the biowaste generated by the large shrimp and crustacean industry in Thailand could bring large potential economic benefits to the country. Chitosan obtained from such wastes has been reported to having a lipid absorbing capacity. The production of a snack with cassava starch and chitosan would not only lead to good application of these abundantly available substances but also lead to a product with an inherent functional characteristic of slimming. The main aim of this study was to investigate the changes in pasting properties of cassava starch mixed with chitin and chitosan obtained from shrimp biowaste and other ingredients used in the formulation of chips and extruded snacks. While chitosan had similar effect on corn, rice and cassava starch, there were differences in cassava pasting properties between chitin and chitosan addition. This suggests the possibility of formation of a complex between chitosan and starch. Slu·imp protein, salt and chitosan affected starch paste and texture, thus leading to a formulated mixture with properties closer to corn starch and rice flour, substances with which commercial snacks are common. The chips and extruded products obtained formulated have shown to be acceptable in term of measured instrumental quality. There is a good potential for such a formulation and process to provide both a cassava starch application and utilisation of a biowaste component like chitosan, while generating a major profits by producing a healthy snack.