SOY LECITHIN-MONOESTER INTERCHANGE REACTION BY MICROBIAL LIPASE

Modification of the fatty acid composition of soy lecithin, principall y at its 1-position, was investigated by interchange reaction with the methyl ester of individual fatty acids and a lipase as the catalyst. The consequent effect on the surface activity of soy lecithin was also examined. The interchange reaction was carried out by heating a mixtu re of soy lecithin and methyl ester of a fatty acid at 60 degrees C fo r 48 h with 10% (by weight of the reactants) Mucor miehei lipase. The lipase was filtered from the reaction mixture, and the product was iso lated by combination of acetone extraction, which removed the methyl e ster fraction, and by preparative thin-layer chromatography separation . The soy lecithin showed distinct change in its fatty acid compositio n in the sn-l position. Capric acid was incorporated by 8.4%, while la uric acid and myristic acid were introduced at 14.1 and 15.7%, respect ively. The linolenic acid percentage was increased by about 10 units. The interfacial tension of soy lecithin changed significantly after in corporation of Various saturated fatty acids.