Production and structural analysis of triacylglycerols containing capric acid and conjugated linoleic acid isomers obtained by enzymatic acidolysis

BACKGROUND: Structured lipids containing medium-chain fatty acids have interesting applications as reduced-calorie fats; moreover, conjugated linoleic acid (CLA) isomers have shown interesting biological properties. The aim of this study was to synthesize triacylglycerols (TAGs) containing capric acid in the sn-1- and sn-3-positions and CLA isomers in the sn-2-position, using different commercial available lipases. RESULTS: The homogeneous CLA-TAGs (Tri-CLA) were chemically synthesized starting from glycerol and CLA isomers, 9-cis, 11-trans and 10-trans, 12-cis CLA. The acidolysis reactions of Tri-CLA with capric acid were carried out at 55 degrees C for different times in hexane; after 96 h the acidolysis average yield was 65%. The best capric acid incorporation in total TAGs was obtained after 96 h with Lipozyme IM (56.6%). The results of structural analysis carried out on the obtained TAGs showed that both Novozyme 435 and anhydrous Lipozyme IM gave the best incorporation of capric acid in sn-1 (3)-positions (61.8%). However, anhydrous Lipozyme IM gave also the highest CLA percent content in sn-2-position (73.2%). CONCLUSION: Anhydrous Lipozyme IM appears to be the more effective enzyme in acidolysis reactions to obtain structured TAGs containing CLA isomers in the central position and capric acid at external positions. (C) 2009 Society of Chemical Industry