A thesis submitted in partial fulfillment of the requirements for the degree· of Master of Science in Food Engineering and Bioprocess Technology

Thesis (M. Sc.) - Asian Institute of Technology, 2011

Functional foods become more popular due to their health benefits which relate to its dietary ingredients that may be more than normal nutritional values. Thus, addition of bioactive compounds such as ·polyunsaturated fatty acids (PUFAs) into foods may be destroyed and detrimental effects during processing and during the shelf life of the products. Lipid oxidation, stability of PUF As during processes and storage, and undesirable sensory properties are the major problems, however these problems can be solved by microencapsulation method. This study mainly focused on the parameters affected to encapsulation process of. DHA producing cell (Schizochytrium sp.), such as stirring speed (RPM) and time during emulsion process, ratio of polymers used, and concentration .of cell loading in microcapsules. There were two techniques which used to produce microcapsules. Both techniques were emulsion based, but the first technique contained sodium alginate and resistant starch as the matrix material ·which stabilized by lM calcium chloride solution. The matrix material of second technique was alginate and resistant starch containing 0.5% calcium carbonate reacted with 0.45% acetic acid in canola oil. Microcapsules which produced from first emulsion technique at 600RPM for 40 minutes and loading with 5% DHA producing cell was the best condition to meet the proper characteristics such as uniform small sphere shape (as 55-282 omin diameter). The peroxide value and anisidine value were in acceptable range. The Bedonie test was performed for texture, flavor, and overall acceptance of sample which were chocolate crispy bar which cooperated with 5% DHA producing cell and without cell loading microcapsules. At 95% confident level, the texture of both samples was not significantly different.