Regiospecific analysis by ethanolysis of oil with immobilized Candida antarctica lipase.

A mixture of oil/ethanol (1:3, w/w) was shaken at 30 degrees C with 4% immobilized Candida antarctica lipase by weight of the reaction mixture. The reaction regiospecifically converted FA at the 1- and 3-positions to FA ethyl esters, and the lipase acted on C14-C24 FA to a similar degree. The content of 2-MAG reached a maximum after 4 h; the content was 28-29 mol% based on the total amount of FA in the reaction mixture at 59-69% ethanolysis. Only 2-MAG were present in the reaction mixture during the first 4 h, and 1(3)-MAG were detected after 7 h. After removal of ethanol from the 4-h reaction mixture by evaporation, 2-MAG were fractionated by silica gel column chromatography. The contents of FA in the 2-MAG obtained by ethanolysis of several oils coincided well with FA compositions at the 2-position, which was analyzed by Grignard degradation. It was shown that ethanolysis of oil with C. antarctica lipase can be applied to analysis of FA composition at the 2-position in TAG.