Vessela D. Kortenska

Kinetics of inhibited oxidation of lipids in the presence of 1-octadecanol and 1-palmitoylglycerol

The kinetics of initiated oxidation of sunflower oil methyl esters at 50°C in the presence of the phenolic inhibitorp-methoxyphenol are investigated. It is established that addition of 0.1 M 1-octadecanol and of 0.1 M 1-palmitoylglycerol leads to a 1.5- or 2.3-fold decrease of the rate constant of chain termination on the inhibitor, which proves the blocking of its effect due to the formation of a complex based on a hydrogen bond. The stronger effect of 1-palmitoylglycerol is explained by the presence of two hydroxyl groups in its molecule.

Effects of chain transfer and recombination/disproportionation of inhibitor radicals on inhibited oxidation of lipids

The kinetics of inhibited oxidation of lipids was studied by computer simulation to evaluate the contributions of the recombination/disproportionation of inhibitor radicals and chain transfer to retardation effects. The influence of inhibitor regeneration on the induction periods and inhibited oxidation rate was demonstrated.

The inhibitory activity of natural phenolic antioxidants in the oxidation of lipid substrates

The suppression of the oxidation of triglyceride and methyl esters of lard and olive and sunflower oils by additives of natural phenolic acids (hydroxy and methoxy derivatives ofpara-hydroxybenzoic and cinnamic acids) at 100 °C was studied. The rate constants of the interaction of these acids with peroxyl radicals in the oxidation of cumene at 60 °C were determined by the chemiluminescence method. Caffeic acid is the most efficient lipid antioxidant, exceeding ionol and α-tocopherol.