Kinetic study of β-carotene and lutein degradation in oils during heat treatment

The kinetics of trans-β-carotene and trans-lutein degradation were individually investigated in palm olein and Vegetaline®, at four temperatures ranging from 120 to 180 7°C. HPLC-DAD analysis was carried out to monitor trans and cis carotenoid variations over the heating time at each temperature. In both oils, initial trans-β-carotene and trans-lutein degradation rates increased with temperature. Trans-lutein was found to degrade at a slower rate than trans-β-carotene, suggesting a higher thermal resistance. The isomers identified were 13-cis-and 9-cis-β-carotene, and 13-cis-, 9-cis-, 13'-cis-, and 9'-cis-lutein. In spite of the higher number of lutein cis isomers, their total amount was lower than that of β-carotene cis isomers. Trans and cis carotenoids were involved in degradation reactions at rates that increased with temperature. All degradation rates were generally found to be lower in Vegetaline® than in palm olein. These results were explained by the initial composition of the two oils and especially their peroxide and vitamin E contents. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.