Specific features of lecithin oxidation in organic solvents

The effect of the structurization of a natural surfactant, egg phosphatidylcholine (lecithin, LH), in solutions in organic solvents on the kinetics of its oxidation by molecular oxygen is studied. The oxidation of LH proceeds via chain free-radical mechanism like the oxidation of hydrocarbons and oils; the oxidizability of LH is close to that of cyclohexene derivatives, methyl linoleate, and sunflower oil. The formation of reverse micelles in LH solutions results in a nonlinear dependence of the rate of oxygen absorption on the substrate concentration. Strong oil-soluble antioxidants decelerate oxygen absorption, however, do not suppress intramicellar oxidation. The addition of CaCl₂ causes the disintegration of reverse LH micelles. Resulting LH-CaCl₂ adduct is oxidized at a higher rate than the original LH and catalyzes the formation of radicals through the decomposition of hydroperoxides similarly to acetylcholine chloride.