Preparation of Docosahexaenoic Acid‐Rich Diacylglycerol‐Rich Oil by Lipase‐Catalyzed Glycerolysis of Microbial Oil from Schizochytrium sp. in a Solvent‐Free System

Abstract

AbstractDocosahexaenoic acid (DHA)‐rich diacylglycerol (DAG)‐rich oil was prepared by lipase‐catalyzed glycerolysis of microbial oil from Schizochytrium sp. in a solvent‐free system. The reaction parameters including lipase type, substrate molar ratio, temperature, lipase concentration, and reaction time were screened. The selected conditions were determined as follows: Novozym® 435 (Novozymes A/S, Bagsvaerd, Denmark) as biocatalyst at 8 wt%, substrate ratio (DHA‐rich microbial TAG/glycerol) of 1:1 mol/mol, temperature of 50 °C, and reaction time of 12 hours. Under these conditions, the triacylglycerol (TAG), DAG, and monoacylglycerol (MAG) contents in the product were 36.4%, 48.2%, and 15.4%, respectively. The lipase was reused successively for 18 cycles without significant loss of activity under the conditions given above. Fatty acid composition analysis of the final product showed that the contents of DHA in TAG, DAG, and MAG were 53.9%, 44.9%, and 34.8%, respectively. DHA‐rich DAG has the potential to be used as an ingredient in infant formula to increase the bioavailability of DHA.