ENRICHMENT OF GAMMA-LINOLENIC ACID FROM BORAGE OIL VIA LIPASE-CATALYZED REACTIONS

Three lipase-catalyzed reactions were utilized to enrich gamma-linolen ic acid in borage oil: (i) selective hydrolysis in isooctane by Candid a rugosa lipase immobilized on microporous polypropylene, (ii) selecti ve esterification of free fatty acid from saponified borage oil and n- butanol by Lipozyme IM-20, and (iii) acidolysis of the products of the previous two reactions, that is, unhydrolyzed acylglycerols and unest erified free fatty acid. In the selective hydrolysis, gamma-linolenic acid content could be raised from 23.6 mol% in borage oil to 51.7% in the unhydrolyzed acylglycerols. On the other hand, gamma-linolenic aci d content in free fatty acid could be increased to 87% after selective esterification. Products with 65% gamma-linolenic acid in their acylg lycerols were obtained by means of the acidolysis reaction.