Preparation and Physicochemical Attributes of Refined Liver Oil from Deep‐Sea Dogfish

The liver oil of deep‐sea dogfish, Centrophorus squamosus, was extracted by different physical methods and refined by sequential processes of degumming, neutralization, decolorization, and deodorization. Phosphoric acid effectively eliminated the mucilaginous substances in crude oil to result in triglycerides with permissible contents of peroxides, unesterified fatty acids, volatile compounds, thiobarbituric acid reactive species, and total oxidation values. A synergistic combination of activated charcoal and Fuller's earth could effectively bleach the crude deep‐sea dogfish liver oil (CDLO) for greater clarity and acceptable color characteristics. The adverse odors in the crude oil were eliminated by acetic acid treatment and vacuum deodorization. This study shows that the multistep refining process of CDLO significantly enhances the composition of C_20–22 n‐3 polyunsaturated fatty acids, with the removal of the components responsible for the undesirable physicochemical characteristics.