| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 91 === Abstract
Structured lipids have important physiological functions in human. The purpose of this study is to develop a process for synthesizing structured lipid from soybean oil. The process consists of three main steps: (1) preparation of free fatty acids (FFAs), (2) urea fractionation method, and (3) synthesis of structured lipid. Free fatty acid was produced by enzymatic or alkali hydrolysis in this study. Then, the FFAs was separated by the urea fractionation method. According to the affinity between various free fatty acids and urea, FFAs was partitioned in solution and solid, one phase is saturated and monounsaturated fatty acids (C18:0, C18:1), and the other is polyunsaturated acids (C18:2, C18:3). The resulting saturated and monounsaturated fatty acid and glycerol were employed as substrate in the synthesis of structured lipids catalyzed by Lipozyme.
The optimal condition for urea fractionation : urea/FFA ratio (w/w) - 4/1, ethanol/FFA ratio(v/w) - 12/1, temperature - 4 degree C. The yield of saturated and monounsaturated fatty acid was about 50%. Structured lipid was obtained by the esterification by lipozyme in hexane. The reaction conditions were 1wt%lipozyme, FFA/glycerol molar ratio - 3/1, temperature - 45degree C, molecular sieve - 200%(w/w, against FFA). When the reaction was carried out for 24 and 120 hours , the conversion of structured lipid obtained was 80% and 100%, respectively. From the results, the performance of lipozyme in producing structured lipid was found to be better than others.
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