engleski

Evaluation of a model system for the selective study of the lipid peroxidation process

The effect of molecular environment on the peroxidation of linoleic acid (LA), a polyunsaturated fatty acid (PUFA), initiated by ferrous ions was investigated in acidic and neutral pH conditions. Mixed nonionic surfactants TWEEN®-20/LA micelles were established as a model system to obtain a surfactant-in-lipid aqueous system at high acidity level. The peroxidation of LA was induced by ferrous ions and the kinetics of the produced conjugated dienes was followed by UV measurements and the ferric thiocynate method. Ferrous ions were oxidized only by the preformed LA hydroperoxides, which under established conditions produced lipid alkoxyl and peroxyl radicals as the sole initiators of propagation. Results revealed the LA peroxidation process remained mainly unaffected within the 2.5 < pH < 5.5 range, while highly pH sensitive around pH 7. The propagation process prevailed at optimal concentrations of 500 M of LA and 280 M TWEEN®-20, and at the ferrous ion concentration up to 75 M, irrespective of the buffer used.

polyunsaturated fatty acid / iron(II) / lipid hydroperoxides / lipid oxidation / micelle

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