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

Abstract

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.

Keywords

• yanbian yellow cattle tallow
• diglyceride
• nuclear magnetic resonance hydrogen spectroscopy(1h-nmr)
• fatty acids
• saturability