Enzymatic Synthesis of Structured Triacylglycerols Containing CLA Isomers Starting from sn‐1,3‐Diacylglycerols

The synthesis of structured triacylglycerols (TAG) by the enzymatic reaction between sn ‐1,3‐diacylglycerols ( sn ‐1,3‐DAG) and conjugated linoleic acid (CLA) isomers was studied. Both the substrates of the reaction were produced from vegetable oils, the sn ‐1,3‐DAG from extra virgin olive oil and the CLA isomers from sunflower oil. The enzymatic reactions between these substrates were catalyzed for 96 h by an immobilized lipase from Rhizomucor miehei (Lipozyme IM) and the reactions carried out in solvent were monitored every 24 h by using high‐performance liquid chromatography‐evaporative light scattering detector (HPLC‐ELSD). The enzymatic reactions were carried out in different reaction media (hexane, isooctane and solvent free) and with different CLA/ sn ‐1,3‐DAG ratios. Total % acidic composition and structural analysis data were evaluated to verify the presence of CLA isomers in sn ‐2‐ position of synthesized TAG. The results showed good levels of CLA incorporation in sn ‐1,3‐DAG, from 19.2% of TAG synthesized in solvent free conditions with a 0.5:1 substrate ratio, to 47.5% of TAG synthesized in isooctane with a 2:1 substrate ratio. It was observed that for all the reaction media, the best sn ‐2‐ acylic specificity was obtained with a 0.5:1 substrate ratio.