Quality control of fish oil
It is important to produce fish oil from fresh fish. As fish spoils, enzymes split the oil into its component fatty acids. Ideally, free fatty-acid content should be below 2%, and there should be little oxidation. Oxidation produces peroxides, aldehydes and ketones. The degree of oxidation can be determined by methods which measure these – giving the so-called TOTOX value based on peroxide and anisidine values. Ideally, it should be below 20. For human use, further refining is carried out