Effects of Light on Temperature Dependence of Safflower Oil Oxidation and Tocopherol Degradation

摘要

Light effects on temperature dependence of safflower oil oxidation and tocopherol degradation were studied. Safflower oil was oxidized at 20, 40, 60, or 80°C for 30, 30, 15, and 6 days, respectively, in the dark or under light. Oil oxidation was evaluated with peroxide value (POV) and conjugated dienoic acid (CDA) value, and tocopherols were monitored by HPLC. Safflower oil consisted of palmitic, stearic, oleic, and linoleic acids at 7.3, 2.0, 14.2, and 76.6%, respectively, with tocopherols at 1157.1 mg/kg. Peroxide and CDA values of safflower oil increased while tocopherol contents decreased with the oxidation time and temperature. Light increased and accelerated the oil oxidation and tocopherol degradation. Temperature dependence of the oil oxidation and tocopherol degradation was higher in the dark rather than under light. The results suggest that temperature control could be more essential in the dark rather than under light with regard to the oxidative stability of safflower oil.