Interesterification (acidolysis) of butterfat with conjugated linoleic acid in a batch reactor

Six commercial lipases, in free or immobilized form, were tested for their ability to catalyze acyl exchange between conjugated linoleic acid and anhy drous butterfat under solvent-free conditions. Immobilized Candida antarcti ca lipase exhibited the best activity. Experiments were conducted for this lipase in butterfat to conjugated linoleic acid ratios of 10:1 (vol/vol), t emperatures from 30 to 70 degrees C, enzyme concentrations of 50 to 200 mg/ g of reaction mixture, and water contents of 0.15 to 2% (wt/wt). At the max imum enzyme concentration used, equilibrium was reached within the first 24 h of reaction. The optimum temperature was 50 degrees C. The triacylglycer ol profile of the product butterfat reflected changes in the relative propo rtions of fatty acid residues as the reaction proceeded, with increases in those triacylglycerols containing 46 to 54 carbon atoms and concomitant dec reases in those triacylglycerols containing 34 to 42 carbon atoms.