Patent ID: 7737289

Claim:
A process for enriching polyunsaturated fatty acid (PUFA) acyl groups in a first fatty acid ester mixture which contains PUFA acyl groups and other fatty acid acyl groups, which process comprises: (a) preparing the first fatty acid ester mixture containing PUFA acyl groups and other fatty acid acyl groups; (b) contacting the mixture with a lipase and with water, the water having a pH above 7 and containing a metal salt which forms poorly soluble salts with free fatty acids in water at a pH above 7 and the lipase having a negative selectivity for PUFA acyl groups, so that the other fatty acid acyl groups are hydrolytically split off from the fatty acid ester mixture more rapidly than the PUFA acyl groups, which forms a second fatty acid ester mixture enriched with PUFA acyl groups, together with poorly soluble fatty acid salts, and (c) separating said second fatty acid ester mixture enriched with PUFA acyl groups, wherein said contacting step (b) is limited in order to minimize hydrolysis of PUFA acyl groups.