Abstract:

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 pH, 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 pH condition. Under
these conditions, the total amount of EPA and DHA glycerides was 21.65%, which was influenced in increasing order by
hydrolysis time, pH, 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.

Key words: lipase, small yellow croaker viscera, refined fish oil, EPA glyceride, DHA glyceride