Enzymatic Interesterification of Palm Oil and Fractions: Monitoring the Degree of Interesterification using Different Methods

Interesterification is an important modification technique for fats and oils resulting in the redistribution of the fatty acids among the glycerol backbone and thus changing the physico‐chemical properties of the modified fat. In this study palm oil, palm olein and soft palm mid fraction (PMF) were subjected to both enzymatic (batchwise) and chemical interesterification. The reaction products were characterized before, during and after interesterification by HPLC, pulsed NMR (p‐NMR) and differential scanning calorimetry (DSC). Interesterification led to more uniform triacylglycerol (TAG) compositions with smaller differences in final physico‐chemical properties between the studied substrates. The degree of interesterification was evaluated on the basis of TAG composition and solid fat content (SFC). Significant differences between both methods were observed. The degree of interesterification based on SFC is therefore a better tool to evaluate the rate constant of the reaction as the TAG composition method does not take into consideration the formation of positional isomers at the end of the enzymatic process.