Production of monoacylglycerol of conjugated linoleic acid by esterification followed by dehydration at low temperature using Penicillium camembertii lipase

Conjugated linoleic acid (CLA) has various physiological activities, and a commercial product is a mixture of free fatty acids (named FFA-CLA) which contains almost equal amounts of 9-cis, 11-trans (9c,11t) and 10t,12c isomers. We attempted to efficiently produce monoacylglycerol (MAG) of CLA by lipase-catalyzed esterification. Study on effect of reaction temperature clarified that synthesis of diacylglycerols (DAGs) from MAGs was repressed at low temperature. When FFA-CLA was esterified at 5 °C with 5 molar equivalents of glycerol using 200 U/g mixture of Penicillium camembertii lipase in the presence of 2% water, the degree of esterification reached 89.6% after 45 h and the contents of MAGs and DAGs were 87.0 and 4.5 wt.%, respectively. Triacylglycerols were not synthesized in this Penicillium lipase-catalyzed esterification. After the esterification was conducted for 20 h (the degree of esterification, 80.8%), dehydration was started by evaporation at 5 mmHg using a vacuum pump. The degree of esterification increased concomitantly with dehydration and reached 94.5% after 16 h (36 h in total). The contents of MAGs (main components, 1(3)-isomers) and DAGs were 92.7 and 2.9 wt.%, respectively. Fatty acid compositions in MAGs synthesized with and without dehydration were the same as that in FFA-CLA. These results showed that the esterification system with dehydration is effective for producing MAGs in a high yield.