Kinetic studies on the interesterification of oils and fats using dried cells of fungus

Abstract

The kinetics of enzymatic interesterification of oils and fats, using acetone dried cells of Rhizopus chinensis as a lipase catalyst, have been investigated in a batch operation. To clarify the mechanism of this reaction, several models are discussed under various conditions in terms of the ratio of triglyceride (TG)/fatty acid (FA) and of the water content. First, in the reaction between olive oil and methyl stearate, the parameters involved in each model were determined by the trial-and-error method so as to make the calculated results fit with the experimental data. Then, the models were compared with the experimental data obtained from the reactions with a mixture of stearic and palmitic acid methyl esters, where the proportions of (TG)/(FA) and water content were varied. From the results, the model based on either first order kinetics or on the formation of the glyceride-enzyme complex was confirmed to fit best with the data under a wide range of reaction conditions. This suggests that the fatty acid moiety of TG seems to be exchanged through the glyceride-enzyme complex in the enzymatic interesterification of oils and fats.