Effect of catalytic conditions on the synthesis of new aconitate esters

Sugar cane is a crop which generates large amounts of biomass and a juice rich in highvalue natural molecules. After extracting sugar from the juice, the recovering of various compounds such as organic acids contained in molasses could contribute to increase the competivity of the sugar industry. Therefore, according to the biorefinery approach, we propose to study the chemical conversion of one of these acids, the aconitic acid, by esterification reactions. A new series of aconitate esters have been synthesized by combining aconitic acid and alcohols from natural origin. The effects of experimental conditions have been investigated and have shown that the type of catalysis has a significant effect on the selectivity. Kinectics have thus been performed to determine the best conditions to synthetize enriched compositions in esters. Homogeneous catalysis generates the highest yield in triester. Heterogeneous catalysis(macroporous resins) is prefered for the production of monoesters while catalysis assisted by ionic liquid is adapted to prepare mainly diesters. Green indicators have been discussed according to the calculations performed. The resulting polyfunctional esters are totally biosourced molecules and have a great potential as bioproducts for different applications

Valorisation de la biodiversité des levures dans la zone Océan indien (Réunion, Madagascar). Le cas du métabolisme des arômes chez la levure Saprochaete suaveolens, isolée du fruit du pitahaya

International audienceno abstrac

Integrated process for extraction and formulation in emulsions of active molecules from fresh passion fruits (Passiflora edulis Sims)

Intensified green processes were investigated to extract several classes of active molecules from fresh purple passion fruits, and to prepare emulsions directly by extrusion for the fruit comprehensive utilization. A thermo-mechanical treatment was carried out through a discontinuous process from the edible part and through a continuous process by twin-screw extrusion using the whole fruit. Only mechanical energy was applied to the materials to generate a liquid fraction (filtrate) and a solid residue. Lipid contents of the obtained filtrates ranged from 0.5 to 2.6 g/100 g close to the extractible lipophilic part. Polyphenols extraction was improved when using the whole fruit and with the addition of water in extrusion. In-situ emulsions with droplets sizes between 2 and 8 μm were obtained. Emulsions obtained after extrusion showed an enhanced stability. This way represents a green alternative method to solvent extractions applied to the different parts of the fruit, and leads to bio-based emulsions enriched in vegetable oil, natural antioxidants and emulsifiers, such as phospholipids, proteins, polysaccharides, pectins and polyphenols

Semi‐Siccative Oils and Bioactive Fractions Isolated from Reunion Island Fruit Co‐Product: Two Case Studies

Semi-Siccative Oils and Bioactive Fractions Isolatedfrom Reunion Island Fruit Co-Product: Two Case StudiesAlice Delvar, Pascale de Caro,* Yanis Caro,* Alain Shum Cheong Sing, Rudy Thomas,and Christine RaynaudThis paper focused on the use of agro-industrial wastes of strawberry guava (Psidiumcattleianum) and passion fruit (Passiflora edulis) generated by the agriculturalindustry on Reunion Island, according to two routes: extraction of semi-siccative oilsfrom the seeds and extraction of bioactive compounds from residual pulp and peels.Oil content, fatty acid, carotenoids, tocopherol, and sterol concentrations aredetermined in the seed oils obtained by four different extraction processes usingSoxhlet extraction, extraction by hexane and ethanol, mechanical pressing andsupercritical-carbon dioxide (SC-CO2) extraction. The oil extraction yields ranged from15 to 30% w/w for strawberry guava and passion fruit, respectively. Both oils areclassified as semi-siccative and had a similar total unsaturated fatty acid content(88%) with a prevalence of linoleic acid (70–78%). High contents in phytosterols andinα-tocopherol are particularly detected in strawberry guava oil. The antioxidantactivities of the bioactive compounds extracted by water and ethanol from pulp andpeels are characterized byα,α-diphenyl-β-picrylhydrazyl (DPPH) test. After purificationon polymeric resin, significant antioxidant activities are recorded (half maximalinhibitory concentration (IC50) from 11 to 50 g L-1) and are related to polyphenolcontents (20.7 to 42.5 g gallic acid equivalents (GAE)/100 g dry extract).Practical Applications: There is a great interest on the use of tropical fruit wastesbecause of their large availabilities. Strawberry guava and passion fruit are often usedin the food industry, for juice and jam production. The seeds, pulp, and peel residuesare in fact a by-product of their industrial processing, which should be valuablyprocessed instead of just throwing away. We can state that the extracted seed (richin polyunsaturated fatty acids) of strawberry guava and passion fruit can be used inthe industrial production of emulsions, paints, and varnishes. Within the positiveaspects of the study, one can also distinguish the use of these tropical fruit by-products as beneficial sources of many valuable bioactive compounds, for example,carotenoids, tocopherols, phytosterols, and especially polyphenols, for functionalformulations. Moreover, it may be the experimental basis for further developmentand use in food industr

Contribution of trans -aconitic acid to DPPH scavenging ability in different media

The antioxidant properties of trans-aconitic acid (TAA) alone or in the presence of usual antioxidants were assessed by DPPH assay. The IC50 value equal to 70mM was very high compared to usual antioxidants (vitamin C and trolox). A joint experimental/theoretical study suggested that hydrogen atom abstraction in TAA by DPPH was located on –CH2– methylene bridge because the corresponding radical was more stabilized than COO· and CC· radicals. In combination with antioxidants (vitamin C, gallic acid, caffeic acid, trolox), synergy or additivity effects were noticed. The magnitude of the synergistic effect varied between 1.06 and 1.24 depending on the type and concentration of antioxidant for a concentration of TAA equal to 22.3mM. Especially, the addition of TAA at a concentration below 32mM to a solution containing 20μM of vitamin C had a synergy effect. Beyond this concentration, TAA showed an additive effect

Potentialities of molasses from cane sugar crystallization in food formulations

International audienceMolasses are produced together with granulated sugar. Three kinds of molasses are obtained during fractional crystallization : A, B, C molasses issued respectively from the first, the second and the third step of crystallization. Several parameters as the sucrose inversion, the presence of aminoacids, of water, of mineral salts, the alkaline pH, the sugar process duration (3 days) and the high temperature (90°C) favour Maillard reactions. These reactions generate coloured macromolecules and heterocycles that have a strong olfactive impact despite a low concentration. On account of the olfactive notes (Vernin, 1979) reminding «grilled», «roasted», «caramel», «burn» smells, the detection and the quantification of volatile compounds are made. The chemical composition and the potential uses in food formulations are correlated.Twenty four A, B and C molasse samples were collected from Bois Rouge sugar industry (Saint André, Reunion Island) and stored at –18°C temperature until analysis.Ice cream, sweet buns, butter cakes were made according to standard formulas. 10% to 20% of sugar quantity were substituted or added by A, B, C molasses. The traditional formulas and the new formulas were compared by tests about physicochemical and sensorial parameters.In all cases, molasses change sensorial aspects of foods. Among molasses, the C molasse is the most enriched in Maillard reaction products that act the more upon aromatic notes and colouring. Differentiation between the molasses is possible in the formulated foods. Instead of uses in animal foods or substrate of alcoholic fermentations, molasses could be considered as interesting sources of flavourings

Les cafés d'exception : Les cafés gourmets - démarche de labellisation du café "Bourbon pointu"

International audienceno abstrac

Aromatic composition and potent odorants of the “specialty coffee” brew “Bourbon Pointu” correlated to its three trade classifications

International audienceAmongst all kinds of coffee brews, “specialty coffee” is conspicuous in particular by a unique flavour. “Bourbon Pointu” coffee, Coffea arabica var. laurina, born from a spontaneous mutation of the Bourbon variety in Reunion Island, is a “specialty coffee”. This study aims at identifying potent odorants of “Bourbon Pointu” coffee brew according to its three trade classifications “Grand cru”, “Sublime” and “Authentique”. Solid phase extraction (SPE) permits to extract the volatiles. After their identification by gas chromatography–mass spectrometry (GC/MS), the potent odorants are determined by their odour activity value (OAV). The determination of their \OAV\ allowed one to differentiate coffee brews from the three trade classifications. Aromatic composition of “Bourbon Pointu” coffee is characterised by a predominance of aldehydes with high \OAV\ (e.g. (E,E)-nona-2,4-dienal: 13,600) for coffee brews belonging to “Grand cru” classification, of 2-phenylacetaldehyde (270) for coffee brews of “Sublime” classification and of a group of pyrazine compounds (e.g. 2-methyl-5-propylpyrazine: 16,750) for coffee brews of “Authentique” classification

Marine-derived fungi producing pigments: optimization of fermentation conditions using response surface methodology

International audienc

Impact of blanching, sweating and drying operations on pungency, aroma and color of Piper borbonense

International audienceLow pungency, high aromatic potential and red color, give to Piper borbonense its originality when compared to Piper nigrum. Effects of blanching, sweating and drying on these characteristics were assessed. The three operations had no impact on the concentration of piperine and essential oil but affected the composition of essential oil slightly and considerably affected the color of the pepper. The ''wet process " , including blanching, sweating and drying, had the largest impact on the composition of aroma, increasing para-cymene content by 89% and reducing safrole content by 33% in dried pepper compared to fresh. Blanching increased the drying rate thus reducing drying time. Drying had a major impact on color, which changed from red to brown. The biggest differences observed led to reductions of 2.2, 7.9 and 8.4 units in L ⁄ ,a ⁄ and b ⁄ values, when chromatic values measured in fresh pepper were compared to those of dried pepper