The kinetics of trans-b-carotene and trans-lutein degradation were individually investigated in palm olein and Vegetaline ® , at four temperatures ranging from 120 to 180 7C. 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-b-carotene and trans-lutein degradation rates increased with temperature. Trans-lutein was found to degrade at a slower rate than trans-b-carotene, suggesting a higher thermal resistance. The isomers identified were 13-cis-and 9-cis-b-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 b-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. Practical applicationsThis paper presents a kinetic approach of b-carotene and lutein degradation in oils at high temperatures. These conditions mimic deep-fat frying or refining processes of oils. The major results are the identification of reaction intermediates and the kinetic data. In conclusion, this study highlights the different thermal sensitivities of b-carotene and lutein and the influence of the initial oil quality and composition on carotenoid degradation.

The recipes of 50 multi-ingredient dishes consumed by the population in an urban district were noted down. The nutritional value was determined as well as the cook value of the dishes in order to evaluate the severity of the thermal treatment. The recipes were simple and involved steps such as boiling, mixing, and cutting. Fibre contents were rather low except when the leaf stems were included. All the dishes had very high beta-carotene content (15.8-25.0 mg/100 g dry matter) and retinol activity equivalent (RAE) (1.3-2.3 mg RAE/100 g dry matter) because of the high proportion of fresh leafy vegetables (from 41.2% to 58.8% of the total dry matter of the ingredients). When meat was added to the preparation, the micronutrient content (iron, zinc, and retinol) was not increased significantly. In three dishes, a positive correlation was found between the thermal treatment severity and the 13-cis-beta-carotene amount.