Effects of chlorophyll and carotene on lipid oxidation and tocopherols during heating for manufacturing of perilla and rice porridge

The effects of chlorophyll (0.33 mg/kg) and β-carotene (3.3, 9.9, 19.8 mg/kg) addition to a mixture of roasted perilla seeds, rice, and water (30:45:225, w/w/w) on the lipid oxidation and tocopherol contents were studied during heating at 100oC for 120 min to simulate cooking of perilla and rice porridge. Lipid oxidation was evaluated with peroxide values (POV) and conjugated dienoic acid (CDA) values, and chlorophyll, β-carotene, and tocopherols were determined by HPLC, POV, and CDA values were increased during heating, indicating the occurrence of lipid oxidation in the perilla and rice porridge. β-Carotene decreased the POV and CDA values of the samples in a concentration-dependent manner, while the addition of chlorophyll did not affect them. Chlorophyll and β-carotene which were added, and tocopherols naturally present in samples were degraded, following the first order kinetics during heating, and β-carotene protected tocopherols from degradation.