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 coffee fermentation microflora were rich and mainly constituted of aerobic Gram-negative bacilli, with Erwinia and Klebsiella genuses at the highest frequencies. The best population increase was observed with lactic acid bacteria and yeasts, whereas those microorganisms that counted on a pectin medium remained constant during the fermentation step. Qualitatively, lactic acid bacteria belonged mainly to Leuconostoc mesenteroides species but the others microflora were relatively heterogeneous. The microorganisms isolated on pectin medium were Enterobacteriaceae, identified as Erwinia herbicola and Klebsiella pneumoniae, not reported as strong pectolytic strains. Throughout coffee fermentation, 60% of the simple sugars were degraded by the total microflora and not specifically by pectolytic microorganisms.

During the fermentation of Coffea arabica L., the most frequently found pectolytic bacteria were Erwinia herbicola and Klebsiella pneumoniae. These micro‐organisms produce pectatelyase which is unable to depolymerize esterified pectins of mucilage without previous de‐esterification. Furthermore, the optimal activities are observed at pH 8.5 whereas fermentation conditions are acidic (5.3–3.5). The major lactic acid bacteria, Leuconostoc mesenteroides, do not produce pectolytic enzymes. Only a Lactobacillus brevis strain, rarely isolated with a low frequency, shows a polygalacturonase activity compatible with fermentation conditions. Mucilage decomposition seems to be correlated to acidification and not to enzymatic pectolysis. Inoculation with pectolytic micro‐organisms allows microbiological control of the fermentation but does not speed up the process. It would be preferable to use lactic acid bacteria so that the pH remained as close as possible to natural fermentation, where acidification is important. This practice would standardize the coffee fermentation microflora and therefore control the end product quality.

Vitamin A deficiency is a public health issue in developing countries and promoting dietary carotenoids as precursors is a promising strategy. However, carotenoids present in numerous fruits and vegetables are unstable and poorly bioaccessible. This study evaluated these two parameters during in vitro digestion of carotenoids and retinoids from carrot juice, raw and cooked spinach, micronutrient-fortified flour and standards without food matrix. Standards were unstable whereas vitamin A from fortified flour and native food carotenoids were generally better protected by the food matrix (30-100% remaining versus 7-30% for standards). Hydrothermal cooking did not influence spinach carotenoid digestive stability but decreased their contents, phenomenon compensated by a significantly better micellarisation from 15-fold for β-carotene to 72-fold for lutein. Finally, carrot juice provided the greatest amount of bioaccessible provitamin A with 1850 μg/100g dry matter (DM) versus 790 and 80 μg/100g DM in cooked and raw spinach, respectively.

The fatty acid (FA) composition of Oenocarpus bataua oil from 38 samples collected over a large geographical range (i.e. French Guiana and Peru) was analyzed. Fifteen fatty acids were obtained from the mesocarp of this palm species. Oleic (72.7%) and palmitic (18.1%) acids were the predominant FAs. Minor FAs were cisvaccenic acid (2.3%), linoleic acid (1.9%), stearic acid (1.7%), palmitoleic (0.9%) and alpha-linolenic acid (0.8%). The mean lipid content of the dry mesocarp was 51.6%. The O. bataua oil samples analyzed were remarkably rich in a-tocopherol. By contrast, the other fractions of the unsaponifiable matter (sterols, carotenoids) did not show any noteworthy specificity in comparison with common vegetable oils. However, the particularly high percentage in D5-avenasterol of O. bataua oil could serve as a marker for its authentication. Results are discussed in terms of the potential nutritional value of O. bataua oil.

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.

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