A Kinetic Approach to Evaluate the Structure-Based Performance of Antioxidants During Lipid Oxidation

Thermal kinetic parameters of fish oil oxidation, as affected by o-hydroxyl, o-methoxy, and alkyl ester derivatives of p-hydroxybenzoic acid in various concentrations (0.02% to 0.16%) at 35 to 55 °C, were calculated. The average extent of increase (2% to 10%) in the values of free energy of activation, ∆G⁺⁺ , as well as the average extent of change in the Arrhenius equation parameters, including activation energy (E_a , -40.5% to 13.6%) and frequency factor (A, -55.0% to 4.3%), could be employed well to show structure-based performance of antioxidants. Temperature coefficient (T_C ) and Q₁₀ number, which were considered as the quantitative measures of thermal sensitivity of the lipid system, showed changes from -40.3% and -27.2% to 13.5% and 11.5%, respectively, in the presence of the antioxidants.