|Oxidation of fish lipids|
Olcott, H.S. (1962). Oxidation of fish lipids, in: Heen, E. et al. Fish in nutrition. pp. 112-115
In: Heen, E.; Kreuzer, R. (1962). Fish in nutrition. Fishing News (Books): London. XXIII, 447 pp., more
|Available in|| Author |
VLIZ: Biological Resources 
The highly unsaturated lipids of fish are readily susceptible to attack by molecular oxygen. The reaction proceeds by a free radical mechanism, and is therefore by an induction period followed by an accelerating rate of oxygen absorbtion with concurrent irradiation, and heavy metals. Free radicals react with oxygen to yield peroxy radicals, which then abstract hydrogen from substrate yielding hydroperoxides and new free radicals. Ultimately a plethora of reaction products results.The attack of fish lipids by oxygen can be hindered by added antioxidants, which act as free radical chain breakers or as peroxide-decomposers. Unusual synergistic effects are demonstrable with mixtures of antioxidants. No satisfactory theory is available to explain the variations observable with different antioxidants or mixtures, since the results depend to an impredictable extent on the nature of the substrate, the temperature, and other variables. Examples will be given.Nutritional damage from the ingestion of oxidized fish lipids is caused by the toxity of the peroxides, either elicited as such or from further oxidative reactions in vivo. Polymers would be expected to be damaging, insofar as they are no longer nutrionally available. Other of the numerous end-products of oxidation may also have deleterious effects. In general the adverse effects of fish oils ixidized in vitro or in vivo reflect secondary damage, due to the formation of free radicals from the decomposition of peroxides. Thus the ability of free radicals or peroxides to destroy vitamins A and E is reflected by various symptoms. Loss of lysine in stored or heated fish meals is probably due to reaction of carbonyl compounds.