| Summary: | 碩士 === 大葉大學 === 食品工程研究所 === 88 === Structured lipids (SL) are designer triglycerides with desired fatty acids at specific position in one triglyceride molecule as “nutraceuticals, functional foods, and medical or pharmafoods” to target specific diseases, metabolic conditions and for optimal nutrition. At present, all the commercial SL products are produced by chemical synthesis. However, the process requires high temperature and long time. It may cause lipids deterioration and obtain unwanted products. Lipase can synthesize SL under mild reaction conditions, and specifity of the lipase can obtain desired products.
SL is synthesized by commercially immobilized lipases in organic solvents. However, the direct contact with the solvent and fatty acids may cause lipase inactivity. Reverse micelles can protect lipase from direct contact with the solvent and fatty acids. In this study, the ability of an immobilized lipozyme IM77 to modify triolein by incorporation of caprylic acid (C8) to form SL in hexane or reverse micellar system was studied. Response surface methodology (RSM) was used to evaluate the effects of synthesis variables on percent molar conversion of SL by transesterification and expect the optimum conditions.
The result was that enzymatic synthesis of SL by lipase IM77 would reach higher yield under less water condition. The ability of lipase IM77 would be inhibited by water. The reaction of high temperature and short time or low temperature and long time could increase the yield of SL. Furthermore lipase IM77 was more active in organic system than reverse micellar system. Based on contour plots, optimum synthesis conditions were: reaction time, 15 h; temperature, 25 ºC; enzyme amount, 20%; substrate molar ratio, 1:4; and added water, 0%.
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