Li_2025_Food.Chem_493_145855

Sn-2 DHA-enriched triacylglycerols (TAG) were prepared by both lipase-catalyzed esterification and solvent fractionation. The specific-structured triacylglycerol (SST) was synthesized at a molar ratio of algae oil to mixed oleic acid and linoleic acid (3:2, w/w) of 1:5 with 8 % of Lipozyme TL IM at 60 degreesC for 8 h. In the SSTs, the DHA content reached 46 % with sn-2 DHA/total DHA of 50 %. The optimal fractionation conditions were algae oil to solvent (v/v) of 1:6 in acetone (-20 degreesC) for 6 h. DHA in the final fraction was 37 % and sn-2 DHA/total DHA was 60 %. LC-MS analysis confirmed the TAG profiles, showing that SSTs predominantly contained U-DHA-U type TAGs (U, unsaturated fatty acid), whereas the fractionated solids were enriched in S-DHA-S type TAGs (S, saturated fatty acid). The melting points of the final products were below the physiological temperature (36.6-37.3 degreesC), enabling efficient absorption and utilization by the human body.