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

Abstract

Abstract Structured triacylglycerides with medium‐chain fatty acids (caprylic acid) in sn 1‐ and sn 3‐positions and a long‐chain unsaturated fatty acid (oleic or linoleic acid) in the sn 2‐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 sn 1‐ and sn 3‐positions, whereas the sn 2‐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.