| Abstract: | The propensity of polyunsaturated fatty acids (PUFAs) to undergo oxidation plays an important role in the integrity of biological membrane and lipid containing foods. The ability of squalene (SQ), a naturally occurring dehydrotriterpene present in animal and plant tissues, to protect linoleic, linolenic, arachidonic and docosahexaenoic acids against temperature‐dependent autoxidation and UVA (ultraviolet A, 320‐380 nm) mediated oxidation was assessed. The oxidation of PUFAs was protected in varying degrees, with highest protection observed for linolenic, arachidonic and docosahexaenoic acids. Linoleic acid was less protected. At a molar ratio of 7:1 (PUFA:SQ) the inhibition of the oxidation process was 22% in the presence of linoleic acid and about 50% in presence of the other PUFAs tested. The different protection exerted by SQ against PUFAs with different degrees of unsaturation may be accounted for by the higher stability of octadecadienoic acid hydroperoxide isomers compared with respective PUFA hydroperoxides. Observing mild UVA‐mediated oxidation and the temperature‐dependent autoxidation reactions we found similarities in the oxidation pattern and the protection exerted by SQ. These findings suggest that the reaction of autoxidation is predominant and SQ acts mainly as peroxyl radical scavenger. |
