Evaluation the kinetic of peroxide and hexanal formation in ascorbyl palmitate incorporated sunflower oil during accelerated oxidation

Abstract

The effects of temperature (40-80 °C), time (0-28 days), and different concentrations (0-1000 mg/kg) of ascorbyl palmitate (AP) on peroxide value, conjugated diene, triene acids and hexanal contents in sunflower oil kept under accelerated oxidation conditions have been evaluated. Samples with added AP showed lower peroxide values and hexanal contents than their counterparts without AP. While with increasing temperature, the reaction orders for peroxide formation reduced from first to zero order, those for hexanal formation were found to be first order under different experimental conditions. AP reduced the reaction rate constant for peroxide and hexanal formation. The activation energy required for peroxide and hexanal formation ranged from 14.64-89.40 and 1.62-12.14 kJ/mol K, respectively. 400 mg/kg AP, providing the highest activation energies for peroxide and hexanal formation, was found to be the best concentration to enhance the oxidative stability of sunflower oil under defined conditions.