Synthesis and concentration of 2-monoacylglycerols rich in polyunsaturated fatty acids.

Polyunsaturated fatty acids (PUFA) in 2-monoacylglycerols form exhibit various biological activities and have potential applications in food and pharmaceuticals. Preparation of 2-monoacylglycerols was conducted by enzymatic enthanolysis. The effects of lipase type, substrate weight ratio, reaction time and lipase load on the 2-monoacylglycerols content in the crude product were investigated. Lipozyme 435 behaved as 1,3-specific and high-catalytic-activity lipase in this reaction. Under the optimal conditions (ethanol:oil = 3:1 (w/w), 8% Lipozyme 435, 3 h), 27% 2-monoacylglycerols were obtained. After solvent extraction of 2-monoacylglycerols, the abilities of low temperature crystallization and molecular distillation to concentrate 2-PUFA-monoacylglycerols were compared. Low temperature crystallization concentrated 81.13% and 74.29% PUFA by acetonitrile and hexane, respectively, with over 90% in 2-monoacylglycerol forms. Conversely, molecular distillation yielded a PUFA concentration of 72% but decreased the 2-monoacylglycerols content to 69.81%. Thus, the method including enzymatic ethanolysis and low temperature crystallization is suitable for preparation of 2-monoacylglycerols rich in PUFA.