166 research outputs found
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
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).
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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
National audienc
Contribution des techniques séparatives a la diversification des produits de la vigne
National audienc
Intervention of Phenolic Compounds in Plum Technology. 2 Mechanisms of Anthocyanin Degradation
17 ref.International audienc
Les techniques a membranes dans la filiere des produits de la vigne : presentation
National audienc
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