Enhancement of both reaction yield and rate of synthesis of structured triacylglycerol containing eicosapentaenoic acid under vacuum with water activity control.

Production of structured triacylglycerols (sTAG) containing eicosapentaenoic acid (EPA) at the sn-1 (or 3) position using Lipozyme in a solvent-free system was studied. Optimal water activity (a(w)) for the synthesis of the sTAG was investigated. Vacuum was applied to shift reaction equilibrium toward the synthesis reaction by removing by-products. During vacuum application, the water level of the reaction system was controlled at the optimal level by addition of a suitable amount of water at a predetermined interval. Intermittent periodic addition of a suitable amount of water into the reaction mixture made the reaction rate faster than that without adding water. A molar yield of 89.7% of the targeted sTAG was obtained after 16 h reaction with a(w) control during the vacuum application as compared with the yield of 87.0% after 24 h of reaction without a(w) control during the vacuum application.