ISOLATION OF ERUCIC-ACID FROM RAPESEED OIL BY LIPASE-CATALYZED HYDROLYSIS

Three lipases were compared for their ability to hydrolyze high erucic acid rapeseed oil, with the objective of concentrating the erucic acid in a single glyceride fraction. Lipase from Pseudomonas cepacia released all fatty acids rapidly and did not result in selective distribution of erucic acid. Geotrichum candidum lipase released C20 and C22 fatty acids extremely slowly, resulting in their accumulation in the di- and triglyceride fractions. Less than 2% of the total erucic acid was found in the free fatty acid (FFA) fraction. Lipase from Candida rugosa released erucic acid more slowly than C20 and C18 fatty acids at 35 degrees C but only resulted in a limited accumulation of the erucic acid in the di- and triglyceride fractions. However, when hydrolysis catalyzed by C, rugosa lipase was carried out below 20 degrees C, the reaction mixture solidified and was composed solely of FFAs and diglycerides. The diglyceride fraction contained approximately 95% erucic acid while about 20% of the total erucic acid was found in the FFA fraction. It is concluded that hydrolysis at low temperature with C. rugosa lipase results in a higher purity of erucic acid in the glyceride fraction than can be obtained with C. candidum lipase, but with considerable loss of erucic acid to the FFA fraction.