脂肪酶催化猪油与辛酸酸解制备功能性脂反应条件的优化

Optimization of Lipase-catalyzed Acidolysis of Lard with Caprylic Acid to Produce Structured Lipid in Organic Solvent System

目的:探索有机溶剂体系中酶法酸解猪油与辛酸制备减热量型功能性脂的最佳反应条件。方法:采用响应曲面法中的3水平5因子2星点部分因子试验设计,评价酸解反应中的5个关键因素,即酶量、反应时间、反应温度、底物比率和水分添加量及其交互作用对辛酸插入率的影响,确定最佳反应条件。结果:建立了辛酸插入率对5个变量的一个2次多项式数学模型,该模型极显著(P<0.0001),拟合优度良好。通过主效应分析,得出每个因子对模型的贡献程度从大到小依次为反应温度(负效应)>底物比率>反应时间>酶量(在实验范围内,水分不影响辛酸插入率)。借助模型方程产生的等高线图及统计软件,分析得出最大辛酸插入率下各个因子的最适水平分别为酶量16%,反应时间36h,反应温度50℃,底物比率3.8,水分添加量5%。在此条件下辛酸插入率达到了50.5mol%,与模型预测值50.7mol%非常吻合。结论:应用响应曲面法对有机溶剂体系中酶法酸解猪油与辛酸制备减热量性脂的反应条件进行优化是合理可靠,科学迅速的,且有效的。

Objects： To research the optimization of lipase-catalyzed acidolysis of lard with caprylic acid to produce reduced-calorie structured lipid in organic solvent system. Methods： A three-level five-factor fractional factorial design with two star points according to the principles of response surface methodology was adopted. The influences of lipase , reaction time, reaction temperature, substrate mole and added water content and their interactions on the incorporation of caprylic acid into lard were evaluated and the optimum variable combination for the highest caprylic acid incorporation was determined with the assistance of statistical software and the contour plots. Results： A good quadratic polynomial model for caprylic acid incorporation was obtained. According to the ANOVA, the model was significant （ P 〈 0. 0001 ） and there was no lack of fit. According to the analysis of main effect of reaction parameters, the contribution of each variable to the model is in following order： reaction temperature （ negative effect） 〉 substrate mole ratio 〉 reaction time 〉 lipase dosage （ added water content had no significant effect in tested range）. By analyzing the contour plots generated by the model and with the assistance of the statistical software, the optimal levels for each variable under highest caprylic acid incorporation were as follow： lipase dosage 16%, reaction time 36h, reaction temperature 50℃, mole ratio of lard to caprylic acid 1：3.8 and added water content 5%. Under these conditions, the incorporation of caprylic acid into lard was up to50.5mol%, which was consistent with the predicted value 50.7mol% . Conclusion： the above results demonstrated that, optimization of lipase - catalyzed acidolysis of lard with caprylic acid to produce reducedcalorie structured lipids in organic solvent system using RSM was reasonable and efficient. The obtained model was workable in present tested range.