Abstract: Monoglycerides were prepared through alcoholysis and used for the synthesis of MLM-type structured lipids through its esterification with caprylic acid under the catalysis of immobilized 1,3-specific lipase. The optimal esterifcation conditions, as determined using orthogonal array design based on one-factor-at-a-time experiments, were 9% of lipozyme RM IM lipase concentration (on the basis of substrate mass), 14 h of reaction time, 40 ℃ of reaction temperature, and 1:6 of molar ratio of MAGs to caprylic acid. Under these conditions, the incorporation rate of caprylic acid was 60.48%, and 92.84% caprylic acid was distributed at the 1or 3 position of glycerol. Purified MLM-type structured lipids were obtained after subsequent two-step molecular distillation with an incorporation rate of 73.34% for caprylic acid. The physicochemical properties could comply with the national standards of Grade 4 rapeseed oil at least.

Key words: structured lipids, rapeseed oil, monoglycerides, caprylic acid, esterification