Polyunsaturated fatty acids (PUFA) are important ingredients of human diet because of their prominent role in the function of human brain, eye and kidney. α‐Linolenic acid (ALA), a C18, n‐3 PUFA is a precursor of long chain PUFA in humans. Commercial lipases of Candida rugosa, Pseudomonas cepacea, Pseudomonas fluorescens, and Rhizomucor miehei were used for hydrolysis of flax seed oil. Reversed phase high performance liquid chromatography followed by gas chromatography showed that the purified oil contained 12 triacylglycerols (TAGs) with differences in fatty acid compositions. Flax seed oil TAGs contained α‐linolenic acid (50%) as a major fatty acid while palmitic, oleic, linoleic made up rest of the portion. Among the four commercial lipases C. rugosa has preference for ALA, and that ALA was enriched in free fatty acids. C. rugosa lipase mediated hydrolysis of the TAGs resulted in a fatty acid mixture that was enriched in α‐linolenic to about 72% yield that could be further enriched to 80% yield by selective removal of saturated fatty acids by urea complexation. Such purified ALA can be used for preparation of ALA‐enriched glycerides. Practical applications: This methodology allows purifying ALA from fatty acid mixture obtained from flax seed oil by urea complexation.

Consumption of Polyunsaturated fatty acid omega-3 is the most recommended fatty acids which have a health benefits for brain, kidney and eye. The conversion of plant-derived omega-3 (n-3) -linolenic acid (ALA, 18:3n-3) to long-chain eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, can enhance ALA sufficient diets in compare to ALA deficient diets. Alpha-linolenic acid (ALA) was extracted and enriched from flax seed oil. Commercial lipases Candida rugosa, Pseudomonas cepacea and P. fluorescens were used for transesterification of ALA enriched from flax seed oil into olive oil TAG back bone. Gas chromatography of olive oil showed it contained high amounts of oleic acid (C18:1, n-9), linoleic acid (C18:2, n-6) and palmitic acid (C18:0) with 0% of ALA. Among the commercial lipase C. rugosa has more preference to ALA and 27% of ALA was incorporated to TAG back bone of olive oil. In 24 hours reaction time, the ALA concentration in TAG of olive has increased to 26% while oleic acid decreased to 60% and palmitic acid decreased from 25 to 7%. The highest incorporation of ALA into olive oil (29%) occurred for ALA: olive oil mole ratio (1:2). There was a decline in incorporation of ALA in olive oil backbone with an increase in the amount of water. ALA incorporation of 25% occurred with 100 µl water while without water it was 27%; it decreased to 15% with 1 ml of water.