Comparison of the antioxidative properties of caffeic and chlorogenic acids

The antioxidative properties of caffeic and chlorogenic acids during autoxidation of triacylglycerols of sunflower oil at 100 °C were compared. The effects of the two acids within the concentration range 2.8–56.5 × 10−4 M (50–2000 ppm) were investigated. The stabilization factor (F) as a measure of the effectiveness of the antioxidants and the oxidation rate ratio (ORR) as a measure of their strength were determined. It was found that at concentration 2.8 × 10−4 M, the effectiveness and the strength of the two acids were practically the same, while at higher concentrations caffeic acid appeared as a much more effective and stronger inhibitor. The analysis of the kinetic data obtained showed that chlorogenic acid and its radicals participated more readily in side reactions with the hydroperoxides and the lipid substrate than caffeic acid and its radicals did.