EFFECT OF TEMPERATURE ON THE ANTIOXIDATIVE ACTION OF INHIBITORS IN LIPID AUTOXIDATION

Purified lard triacylglycerols have been oxidised at 25, 50, 75 and 100-degrees-C in the presence and absence of 0.2-2.0 g kg-1 (0.45-10.3 mmol litre-1) of the antioxidants alpha-tocopherol and ferulic acid. Increasing the temperature does not influence the effect of ferulic acid on the induction period or the rate of autoxidation, alpha-tocopherol is more effective at extending the induction period and reducing the rate of autoxidation as the temperature is increased. The rate of substrate oxidation increases with increasing alpha-tocopherol concentration, especially at lower temperatures, but decreases with increasing ferulic acid concentration. This behaviour is explained in terms of the participation of antioxidant molecules and radicals in the autoxidation process. High-temperature oxidation results can be extrapolated only to room temperature when no change occurs in the antioxidative mechanism.