LIPASE‐CATALYZED PRODUCTION OF STRUCTURED LIPIDS VIA ACIDOLYSIS OF FISH OIL WITH CAPRYLIC ACID

ABSTRACT Structured lipids containing eicosapentaenoic and docosahexaenoic acids were manufactured in a batch reactor by lipase‐catalyzed acidolysis of fish oil with caprylic acid. The following free lipases (Lipase AP, Aspergillus niger; Lipase P, Pseudomonus sp.; Lipase AY, Candida rugosa; Lipase AK, Pseudomonas fluoresescens; Lipase F, Rhizopus oryzae; Lipase D, Rhizopus delemar) were screened under selected reaction conditions. The conditions were enzyme load 5%, substrate mole ratio 1:6 (fish oil: caprylic acid), and reaction temperature of 50C. Lipase AK had the highest activity and was suitable for production of structured lipids from fish oil. The optimal mole substrate ratio of fish oil to caprylic acid for Lipase AK was 1:6 to 1:8. The time course of the reaction at different enzyme loads demonstrated that 40% incorporation of caprylic acid could be obtained for Lipase AK in 5 h with 10% enzyme load. Addition of water had little effect on the activity of the lipase. Lipase AK and Lipozyme IM were further compared under the same conditions, in which Lipase AK had a slightly higher incorporation of caprylic acid, similar acyl migration of caprylic acid from sn‐1,3 positions to the sn‐2 position, and a slightly lower selectivity towards docosahexaenoic acid.