EFFECT OF PHOSPHOLIPIDS ON ENZYME-CATALYZED TRANSESTERIFICATION OF OILS

The effect of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) on the activity of an immobilized lipase, Lipozyme, during transesterification of oils has been studied. PC concentrations less than 0.05% did not affect the initial rate of transesterification. Higher concentrations of PC as well as PE and PI-rich phospholipids at the 0.5% level caused a reduction in the initial reaction rate, but after ten hours transesterification had progressed to the same extent as the control sample. Reuse of Lipozyme for ten batch reactions showed that a PC content of less than 0.05% did not cause significant inactivation of the enzyme, but PC contents above this level caused progressive inactivation of the enzyme and the inactivation increased with PC content. The ability of phospholipids to inactivate the Lipozyme was in the order PE > PC > PI. Variation in the acyl groups of PC did not significantly affect inactivation of the enzyme. It is concluded that the phospholipid content of edible oils should be reduced below 200 ppm by degumming if unacceptable inactivation of Lipozyme is to be avoided.