响应面法的脂肪酶富集金枪鱼油中二十二碳六烯酸甘油酯工艺优化的研究

Optimization of Lipase-Catalyzed Enrichment of Docosahexaenoic Acid in Tuna Fish Oil by Response Surface Methodology

以金枪鱼副产物为原料提取精炼鱼油,研究了皱褶假丝酵母脂肪酶(Candida Rugosa)富集金枪鱼油二十二碳六烯酸(Docosahexaenoic Acid,DHA)甘油酯的工艺条件。在单因素实验的基础上选取水油质量比、脂肪酶添加量、反应温度和时间4个因素为自变量,以甘油酯中DHA、ω-3含量和甘油酯得率为响应值,采用中心组合(box–behnken)进行响应面实验设计和分析。结果表明,最佳条件为水油比1:1.7,脂肪酶添加量1%,反应温度50℃,反应时间3 h。在此条件下,甘油酯中DHA质量分数为35.55%,ω-3质量分数为42.25%,甘油酯得率为73.85%。本课题成功建立了甘油酯中DHA、ω-3含量(R2=0.8832)和甘油酯得率(R^2=0.9425)的拟合模型。卡方检验分析表明这两种模型的预测值和实测值无显著性差异(P>0.05)。

Present study aimed to enrich the docosahexaenoic acid (DHA) content in tuna fish oil extracted from by-products of tuna fish processing by using lipase-catalyzed hydrolysis method. Lipase (triacylglycerol ester hydrolases, EC 3.1.1.3) specifically lipase from Candida Rugosa was used to selectively hydrolyze tuna fish oil in order to enrich the DHA content in glyceride fraction of fish oil. A single factorial study was conducted in order to determine the levels for the four investigated variables namely weight ratio of water to oil, enzyme content, reaction temperature and reaction time. A box–behnken design was then used to optimize the variables. Optimal reaction conditions were: 1:1.7 weight ratio of water to oil, 1 wt% enzyme load, 50 oC of reaction temperature and 3 h of reaction time. Following lipase-catalyzed hydrolysis reaction at optimal conditions, the mass fraction of DHA was 35.55% in the hydrolyzed oil and omega-3 fatty acids was 42.25% with a final glyceride yield of 73.85%. Well-fitting models were successfully established for DHA content (R^2 = 0.8832) and glyceride yield (R2 = 0.9425) through multiple linear regressions with backward elimination. Chi-square test indicated that there were no significant (P > 0.05) differences between the observed and predicted values for both models.