Borago officinalis oil: Fatty acid fractionation by immobilized Candida rugosa lipase

gamma-linolenic acid (Z,Z,Z-6,9,12-octadecatrienoic acid), a very important polyunsaturated fatty acid is found in the free fatty acid fraction prepar ed by the hydrolysis of borage oil. Our aim was to enrich this fraction in gamma-linolenic acid using selective esterification. Candida rugosa lipase was used as catalyst after immobilization on the following ion-exchange res ins: Amberlite IRC50, IRA35, IRA93, and Duolite A7, A368, A568. In every ca se, immobilization modified the lipase's specificity: palmitic, stearic, ol eic, and linoleic acids were preferentially esterified compared to gamma-li nolenic acid, thus allowing a gamma-linolenic acid enrichment of 3.0.