Enhanced Enzymatic Preparation of Lipophilic Feruloylated Lipids Using Distearin as Feruloyl Acceptors: Optimization by Response Surface Methodology

Abstract

Feruloylated lipids are esters of ferulic acid, which have antioxidation and UV-absorbing activities. In this study, lipophilic feruloylated lipids were prepared by the enzymatic transesterification of ethyl ferulate (EF) with distearin. Effects of different diacylglycerols as feruloyl acceptors were compared. Effects of transesterification variables were studied and optimized using response surface methodology. Under the optimized conditions (reaction temperature 78°C, reaction time 24 h, and enzyme load 14%), EF conversion was 97.6±2.2%, and the lipophilic feruloylated lipids prepared by the transesterification were consisted of 43.2±0.9% feruloylated monoacylglycerols (FMAG) and 33.3±1.3% feruloylated diacylglycerols (FDAG), respectively. Analysis of variance (ANOVA) showed that the regression equation was adequate for predicting the transesterification. The activation energies for the transesterification of EF with distearin to form lipophilic FMAG + FDAG and the side reaction hydrolysis of EF to form glyceryl ferulate + glyceryl diferulate were 57.75 and 40.31 kJ/mol, respectively.