Lipase-Catalyzed Enrichment of EPA and DHA Glycerides from Visceral Oil of Small Yellow Croaker

Objective: The refined fish oil extracted from gut organs of small yellow croakers was hydrolyzed by lipase to enrich eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA) glycerides. Methods: Gas chromatography(GC) combined with peak area external standard method was used to determine the contents of EPA and DHA glycerides. Onefactor-at-a-time method followed by response surface analysis was used to analyze the effects of p H, temperature, enzyme amount and hydrolysis time on enrichment efficiency. Results: The optimal conditions for enriching EPA and DHA glycerides were found to be hydrolysis at 30 ℃ for 4 h with an enzyme dosage of 1.0% under neutral p H condition. Under these conditions, the total amount of EPA and DHA glycerides was 21.65%, which was influenced in increasing order by hydrolysis time, p H, temperature and enzyme dosage. Conclusion: The physical and chemical indexes and sensory evaluation of EPA and DPA-enriched fish oil were better than those of fish oil before enrichment with a 1.74-fold increase in the total of EPA and DHA glycerides. As a result, the natural EPA and DHA glycerides were obtained.