Chemical transesterification of tuna oil to enriched omega-3 polyunsaturated fatty acids

The effect of reaction conditions on transesterification of tuna oil with n−3 fatty acid methyl ester (n−3 FAME) using sodium methoxide as catalyst was studied. The lipid and fatty acid composition of the reaction products were analyzed. The time course of the reaction indicated that the highest incorporation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) occurred after 5 h, and did not change significantly during the next 20 h (P⩾0.05). The catalyst concentration of 1.5% w/w of reactants showed the highest incorporation of EPA and DHA. Incorporation of EPA and DHA were increased with increasing reaction temperature (P<0.05) and the highest incorporation was observed at 80 °C. The highest EPA and DHA incorporation occurred at a mole ratio of tuna oil and n−3 FAME of 1:4. The recovery of triglyceride was decreased with the increasing of all reaction factors. Tuna oil enriched with n−3 fatty acids was successfully produced by chemical interesterification.