Research on the ability of enriching docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from fish oil (PANGASIANODON HYPOPHTHALMUS)

Abstract

Fish waste is a current problem in the fish processing industry due to huge waste for raw materials and negative environmental impact. Fish waste can be used to produce oil, bio-diesel or to obtain numerous bioactive compounds. Especially, fish oil is rich in DHA and EPA which can be produced as food supplement and medicine for various treatment. The challenge is to develop environmentally friendly and economically feasible techniques for enriching DHA and EPA from fish oil in Vietnam conditions. In this study, the fatty acid content in pangasianodon fish oil (Pangasianodon hypophthalmus) was determined, especially some essential fatty acids which were alpha-linolenic acid of 0.66%, docosahexanoic acid of 0.50%, and eicosapentaenoic acid of 0.45%. The fatty acids were extracted from pangasianodon fish oil by hydrolysis reaction. The factors affecting the hydrolysis reaction were determined as KOH concentration of 1N, the KOH-to-fish oil ratio of 2.5, temperature of 70°C and time of 1 hour in order to achieve the highest hydrolysis's efficiency of 94.90%. DHA and EPA were enriched by urea complexation. At the same time, the optimization method was used to build the relationship between mathematics and technology to determine the technological mode of enrichment process at the urea-to-fish oil ratio of 2.1, complexation temperature of -11°C and complexation time of 18.6 hours. Under these conditions, the enrichment efficiency of DHA, EPA and omega-3 reached to maximum level of 120.06%, 58.40% and 179.50%, respectively. The results were totally compatible with experiments and able to apply in the fish processing industry. The enrichment technology process of DHA, EPA from pangasianodon fish oil has been established to produce high quality fish oil which contented high polyunsaturated fatty acids and to enhance the value of fish oil. Keywords: pangasianodon, fish oil, enrichment, optimization, urea complexation