Enzymatic preparation of structured triacylglycerides containing γ-linolenic acid

Abstract Structured triacylglycerides (STAG) rich in γ-linolenic acid (GLA) were prepared using a three-step process. First, with the addition of molecular sieves (MS) at different addition times (3, 9, 12 and 15 h) and loads (2.5, 5, 10 and 15%, based on the total weight of substrates), the enrichment of GLA from evening primrose oil (EPO) and 1-butanol (BtOH) was improved via Candida rugosa lipase-catalysed esterification reactions. Secondly, the GLA-enriched fraction was separated by thin-layer chromatography (TLC) to be further set to react during the third step in the presence of glycerol and Candida antarctica fraction B (CALB), under different enzyme loadings (5, 10, 15 and 20%, based on the total weight of substrates), temperatures (30, 40, 50 and 60 °C) and substrates molar ratios (1:1, 2:1, 3:1 and 4:1, glycerol:GLA). 60% of STAG containing 49 wt% of GLA were produced by using 15% of CALB at 60 °C and a 3:1 molar ratio.