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 aci d in a single glyceride fraction. Lipase from Pseudomonas cepacia rele ased all fatty acids rapidly and did not result in selective distribut ion of erucic acid. Geotrichum candidum lipase released C20 and C22 fa tty 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 rugo sa 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 a cid in the di- and triglyceride fractions. However, when hydrolysis ca talyzed by C, rugosa lipase was carried out below 20 degrees C, the re action mixture solidified and was composed solely of FFAs and diglycer ides. The diglyceride fraction contained approximately 95% erucic acid while about 20% of the total erucic acid was found in the FFA fractio n. It is concluded that hydrolysis at low temperature with C. rugosa l ipase results in a higher purity of erucic acid in the glyceride fract ion than can be obtained with C. candidum lipase, but with considerabl e loss of erucic acid to the FFA fraction.