Abstract:

Fish oil is usually extracted from the wastes during fish processing. In this paper, fish oil extraction from viscera of channel catfish, Ictalurus punctatus, through a modified potassium hydroxide hydrolysis method, was investigated. The best extraction efficiency was obtained at the hydrolysis condition of pH 7.0, 1:1.5 of viscera-water ratio, 65 ℃ for hydrolysis temperature, 35 min for hydrolysis time, 4% potassium chloride, and 10 min for salting-out. The extraction rate of fish oil was up to 82.09% under this optimal condition. The relative content of saturated fatty acids accounted for 20.59% of total fatty acids. The relative content of monounsaturated fatty acids and polyunsaturated fatty acids were 54.48% and 15.18%, respectively. The ratio of n-3 to n-6 polyunsaturated fatty acids is 3.29, which was higher than that of other fresh water fish. Therefore, viscera of channel catfish provided a good resource for fish oil production.

Key words: Ictalurus punctatus, viscera, fish oil, extraction, fatty acid