延黄牛脂制备高纯度1,3-甘油二酯工艺

目的:提高延黄牛脂的附加值。方法:采用固定化脂肪酶Lipozyme RM IM为催化剂,牛油脂肪酸乙酯(乙醇解法自制)和甘油为原料制备1,3-甘油二酯,运用氢谱考察脂肪酶添加量、底物摩尔比、反应时间以及反应温度对粗反应混合物中1,3-甘油二酯含量的影响,并阐明醇解酯交换前后牛油与甘油二酯产物的脂肪酸组成变化。结果:1,3-甘油二酯合成最佳条件为脂肪酶Lipozyme RM IM质量分数为1%,底物摩尔比(n_{脂肪酸乙酯}∶n_甘油)2∶1,反应时间6 h,反应温度50℃。此条件下的1,3-甘油二酯生成率为72.5%,甘油酯得率为77%;纯化后纯度提高至90.79%。与原油(延黄牛脂)相比,甘油二酯产物中亚油酸和油酸含量分别升高了13.65%,6.47%,饱和度降低了7.17%。结论:延黄牛脂制备1,3-甘油二酯不仅能改变甘油酯结构,还可以改变牛脂的脂肪酸组成,降低其饱和度。

Study on preparation of high purity 1,3-diglyceride from Yanhuang beef tallow

Objective:This study aimed to increase the added value of Yanbian yellow cattle fat.Methods:Using immobilized lipase Lipozyme RM IM as a catalyst,and tallow fatty acid ethyl ester(self-made by ethanol hydrolysis)and glycerol as raw materials to prepare 1,3-diglyceride,using nuclear magnetic resonance to investigate the effect of lipase addition,substrate molar ratio,reaction time and reaction temperature on the content of 1,3-diglyceride in the crude reaction mixture.The changes in fatty acid composition of the tallow and diglyceride products was clarified before and after the alcoholysis and transesterification.Results:The best conditions for the synthesis of 1,3-diglycerides were the addition of 1%(mass fraction)of lipase Lipozyme RM IM,with the molar ratio of substrate of 2∶1,and reaction for 6 h,at 50℃.Under the control of those conditions,the production rate of 1,3-diglycerides was 72.5%,and the yield of glycerides was 77%;the purity increased to 90.79%after purification.After testing,compared with crude oil(flavored tallow),the content of linoleic acid and oleic acid in the diglyceride product increased by 13.65%and 6.47%,respectively,and the degree of saturation decreased by 7.17%.Conclusion:the preparation of 1,3-diglycerides from Yanbian Yellow Cattle fat changes not only the glyceride structure,but also the fatty acid composition of cattle fat and reduces the saturation.This experiment enables the high-quality utilization of Yanbian Yellow Cattle fat.