Two‐step enzymatic reaction for the synthesis of pure structured triacylglycerides

Abstract

AbstractStructured triacylglycerides with medium‐chain fatty acids (caprylic acid) in sn1‐ and sn3‐positions and a long‐chain unsaturated fatty acid (oleic or linoleic acid) in the sn2‐position of glycerol (MLM) were synthesized by lipase catalysis in a two‐step process. First, pure 2‐monoacylglycerides (2‐MG) were synthesized by alcoholysis of triacylglycerides (triolein, trilinolein, or peanut oil) in organic solvents with 1,3‐regiospecific lipases (from Rhizomucor miehei, Rhizopus delemar, and Rhizopus javanicus). The 2‐MG were purified by crystallization and obtained in up to 71.8% yield. These 2‐MG were esterified in a second reaction with caprylic acid in n‐hexane to form almost pure MLM. For 2‐MG obtained from peanut oil, the final product contained more than 90% caprylic acid in the sn1‐ and sn3‐positions, whereas the sn2‐position was composed of 98.5% unsaturated long‐chain fatty acids. Reaction conditions for both steps were optimized with respect to source and immobilization of lipase, water activity, and solvent.