GAMMA-LINOLENIC ACID CONCENTRATES FROM BORAGE AND EVENING PRIMROSE OIL FATTY-ACIDS VIA LIPASE-CATALYZED ESTERIFICATION

gamma-Linolenic acid (GLA, all-cis 6,9,12-octadecatrienoic acid) has b een enriched from fatty acids of borage (Borago officinalis L.) seed o il to 93% from the initial concentration of 20% by lipase catalyzed se lective esterification of the fatty acids with n-butanol in the presen ce of n-hexane as solvent. The immobilized fungal lipase preparation, Lipozyme, used as biocatalyst, preferentially esterified palmitic, ste aric, oleic and linoleic acids and discriminated against GLA, which wa s thus concentrated in the unesterified fatty acids fraction, In the a bsence of hexane, concentrate containing about 70% GLA was obtained. W hen the reaction conditions, optimized for borage oil fatty acids, wer e applied to fatty acids of evening primrose (Oenothera biennis L.) oi l, concentrates containing 75% GLA were obtained. From both oils, GLA concentrates were prepared efficiently in short reaction times (1-3 h) at 30-60 degrees C, The process can be applied for the production of GLA concentrates for dietetic purposes.