Enrichment of Alkylglycerols and Docosahexaenoic Acid via Enzymatic Ethanolysis of Shark Liver Oil and Short-path Distillation

Abstract

ABSTRACT Enzymatic alcoholysis of squalene-free shark liver oil (SLO) for the enrichment of alkylglycerols (AKG) and docosahexaenoic acid (DHA) was investigated. The squalene-free SLO contained 75.11% triacylglycerols (TAG) and 18.69% diacylglycerol ethers (DAGE), and its DHA and total AKG contents were 7.52% and 6.17%, respectively. The catalytic discrimination against both DAGE and DHA was observed during the reaction, and the discrimination against DAGE was affected by lipase and reaction conditions. The ethanolysis reaction was carried out at 40°C for 24 h, where the reaction medium contained 20% ethanol and 3% Lipozyme® 435. The ethanolysis derivatives with 62.96% monoacylglycerol ethers, 30.93% monoacylglycerols, and 5.88% DAGE were obtained followed by short-path distillation, and its DHA and total AKG contents were improved to 23.17% and 33.98%, respectively. The study provides an approach for value-added utilization of SLO with low contents of AKG and n-3 polyunsaturated fatty acids.