Lipase-catalyzed interesterification of soybean oil with an ω-3 polyunsaturated fatty acid concentrate prepared from sardine oil

Toreduce the content of limoleoyl moiety in soybean oil, soybean oil that contains 53.0% linoleoyl moiety as molar acyl moiety composition was interesterified with an ω-3 polyunsaturated fatty acid (PUFA) concentrate (240 mol% elcosapentaenoic acid [EPA], 40.4 mol% docosahexaenoic acid [DHA]) prepared from sardine oil, using an immobilized sn-1,3-specific lipase from Rhizomucor michei (Lipozyme IM). The reaction was carried out in a batch reactor at 37°C under the following conditions: 500 μmol of soybean oil, molar ratio of ω-3 PUFA concentrate to soybean oil=1.0–6.0, 5.0 mL of heptane, and 30 batch interesterification units of enzyme. After the reaction time of 72h, modified soybean oil, which contains 34.9% linoleoyl, 10.1% eicosapentaenoyl, and 14.2% docosahexaenoyl moieties, was produced at the molar reactant ratio of 6.0. In this oil, the total ω-3 acyl moiety composition reached 34.1%; the molar ratio of ω-3 to ω-6 acyl moieties was enhanced by five times compared with soybean oil. Compared with palmitic acid, DHA was kinetically six times less reactive, although the EPA was by 16% more reactive.