Production of n-3 polyunsaturated fatty acid-enriched fish oil by lipase-catalyzed acidolysis without solvent

Fish oil rich in n‐3 polyunsaturated fatty acid (n‐3 PUFA) was prepared by nonsolvent enzymic acidolysis. n‐3 PUFA‐enriched fish oil contained 25% eicosapentaenoic acid (EPA) and 40% docosahexaenoic acid (DHA). In acidolysis of cod liver oil, EPA content of the original fish oil was reduced at 5 h, but DHA content of the fish oil increased. It was assumed that EPA in the fish oil was replaced by DHA to reach a new chemical equilibrium. Two‐stage acidolysis, which was carried out under CO2 replacement early (about 3 h) and also in vacuum at 5–24 h, was effective for reduction in the content of diacylglycerol, which was formed by reverse reaction, hydrolysis. This method has industrial significance because PUFA‐enriched triacylglycerol is easily separated from the reaction mixture by molecular distillation.