Ethanol triggers grape gene expression leading to anthocyanin accumulation during berry ripening

Recent studies have shown that low doses of ethanol stimulate the maturation of some fruits. The present work showed that spraying Cabernet Sauvignon grapes, with 5% ethanol at veraison enhances the anthocyanin accumulation. Veraison is the time when the berries turn from green to purple. HPLC analysis showed a marked increase in the total concentrations of the derivatives of delphinidin, cyanidin, petunidin, peonidin and malvidin from the fourth day after the ethanol treatment until harvest. This was not linked to a difference in berry weight in comparison to controls. Two distinct expression patterns were found for anthocyanin biosynthesis genes in the treated and untreated berries. For one group, consisting of chalcone synthase, flavanone-3-hydroxylase, dihydroxyflavonol-4-reductase and leucoanthocyanidin dioxygenase, the expression was inhibited or unchanged by the ethanol treatment, whereas for UDP glucose-flavonoid 3-O-glucosyltransferase (UFGT) there was a marked increase in expression from 1 to 20 days after ethanol treatment. These results suggest that the UFGT gene is a key factor in the observed anthocyanin accumulation following ethanol treatment

Stabilisation tartrique : quand les ions potassium déchargent le vin

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Dosages des polyphenols des moûts de raisin *

L'étude de la réaction de Folin Giocalteu en solution modèle a montré que ce réactif ne peut être utilisé directement sur les moûts de raisin, en particulier s'il s'agit de moûts mutés. Une méthode d'isolement est proposée pour l'évaluation de mesures globales de polyphénols (Folin Giocalteu, hydrolyse acide, réaction avec la vanilline, spectre UV). +++ A study of the reaction of Folin Giocalteu in a sample solution revealed that this reactive agent cannot be used directly in grape musts, especially for preserved musts. An isolation method is proposed to evaluate total polyphenol measurements (Folin Giocalteu, acid hydrolysis, vanillini reaction, UV spectrum).   * Travail effectué avec la collaboration de H. Fea

Etude du conditionnement de vins en bag-in-box

*INRA/ISVVM, place Pierre Viala, 34060 Montpellier Cedex 1 (FRA) Diffusion du document : INRA/ISVVM, place Pierre Viala, 34060 Montpellier Cedex 1 (FRA)National audienc

Pré-traitement des raisins par flash-détente sous vide et caractéristiques des vins

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Contribution des techniques séparatives a la diversification des produits de la vigne

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Dossier spécial: les gaz en oenologie. L'oxygène dissous dans les vins

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Intervention of Phenolic Compounds in Plum Technology. 2 Mechanisms of Anthocyanin Degradation

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Des enzymes pour améliorer les vins

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Les techniques a membranes dans la filiere des produits de la vigne : presentation

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