酶法全酯化合成富含EPA/DHA甘油酯工艺研究

以富含EPA/DHA的脂肪酸为底物,采用两步酶法合成富含EPA和DHA的甘油酯。首先,以T1脂肪酶为催化剂催化富含EPA/DHA的脂肪酸和甘油反应;在最优条件为:反应温度40℃,水分添加量为底物混合物的3%、甘油与脂肪酸摩尔比3∶1和酶添加量50 U/g底物混合物时,富含EPA/DHA的脂肪酸的转化率达到62%以上,此时产物中甘油三酯、甘油二酯、甘油单酯的质量分数分别为10.52%、38.15%、25.64%。将游离酶催化酯化反应产物中的油相回收,利用自制的固定化CALB(LipozymeCALB L固定于环氧树脂ECR8285上)为催化剂,在真空条件下继续催化未反应的脂肪酸与偏甘油酯(甘油单酯和甘油二酯)继续酯化反应12 h,此时产物中甘油三酯、甘油二酯和甘油单酯的质量分数分别达到38.34%、51.02%、10.63%,没有检测到脂肪酸的存在。

Production of EPA/DHA-enriched glycerides by enzymatic holoesterification process

In this study, a two-step esterification process was developed for the synthesis of EPA/DHA-enriched glycerides using EPA/DHA-enriched polyunsaturated fatty acids as substrates. First, a free lipase was employed to catalyze esterification of EPA/DHA-enriched fatty acids and glycerol. The conversion of EPA/DHA-enriched fatty acids as high as 62% with triacylglycerol, diacylglycerol and monoacylglycerol content of 10.52%, 38.15% and 25.64% was obtained under the optimized conditions: reaction temperature of 40°C, water addition of 3% (w/w, with respect to the total substrates), molar ratio of glycerol to EPA/DHA-enriched fatty acids 3:1, enzyme loading of 50U/g (U/g, with respect to the total substrates). Subsequently, the oil phase obtained in the first step was collected and an immobilized candida antarctic lipase B (Lipozyme ?CALB immobilized onto an epoxy resin ECR8285) was employed to further esterify the unreacted EPA/DHA-enriched fatty acids with monoacylglycerol or diacylglycerol under vacuum. After 12h of reaction, the content of triacylglycerol, diacylglycerol, monoacylglycerol reached to 38.34%, 51.02% and 10.63% respectively and no fatty acids were detected in the final products.