Résumé
The aim of this study was to gain further insight into b-carotene thermal degradation in oils. Multiresponse modeling was applied to experimental highperformance liquid chromatography–diode array detection (HPLC–DAD) data (trans-, 13-cis-, and 9-cis-b-carotene concentrations) during the heat treatments (120–180 C) of two b-carotene-enriched oils, i.e., palm olein and copra. The test of different reaction schemes showed that b-carotene isomerization reactions were dominant and reversible. The resulting cis isomers and trans-b-carotene simultaneously underwent oxidation and cleavage reactions at the same rate constant. From the kinetic analysis, it appeared that—contrary to oxidation and cleavage reactions—isomerization rate constants did not follow the Arrhenius law. However, the isomerization equilibrium constant increased with temperature, favoring isomer production, particularly 9-cis-b-carotene. Its production was shown to be concomitant with oxidation and cleavage reactions, indicating that 9-cis-b-carotene could be a good degradation indicator during oil storage or processing.