Lipase-catalyzed transesterification of ethyl ferulate with triolein in solvent-free medium

Abstract

The lipase-catalyzed transesterification of ethyl ferulate with triolein in a solvent-free medium was investigated. Transesterification was catalyzed by immobilized lipase from Candida antarctica (Novozym 435), to form ferulyl oleins, a mixture of ferulyl diolein and ferulyl monoolein. These ferulated esters can be widely used as natural antioxidant in both lipid containing food and cosmetic applications. External mass transfer limitations were lowest, when the agitation speed was higher than 180 rpm. A linear relationship between the initial reaction rate and enzyme load up to 10% demonstrated that the internal diffusion limitations could be minimized. The effects of various parameters on yields and rates of reaction were studied in the absence of mass transfer limitations. The initial reaction rate increased when the reaction temperature was raised in the range of 45–65 °C, further increase to 70 °C decreased the final yield to 48.9%. The value of activation energy was calculated as 65.04 kJ/mol based on the Arrhenius law. Under the most favorable conditions, a kinetic model based on the ping–pong bi–bi mechanism with triolein inhibition was found to fit the initial reaction rate data very well and the kinetic parameters were evaluated by non-linear regression analysis.