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Theses

IMPACT DES ENZYMES DE MACERATION SUR LA COMPOSITION EN POLYSACCHARIDES ET EN POLYPHENOLS DES VINS ROUGES – ETUDE DE L'EVOLUTION DE CES COMPOSES EN SOLUTION MODELE VIN.

Abstract : Conversion of grape berries in wine is a complex process. Technological auxiliaries such as enzymes have been developed to improve wine quality. This quality depends on the phenolic composition: anthocyanins are responsible for wine colour and tannins for astringency. Macerating enzymes, that degrade grape berry cell walls, are used to improve yield of free run juice and increase extraction of pigments and tannins. However, these treatments remain empirical and conflicting results have been obtained on their effect on the release of pectic polysaccharides from the cell walls and on the phenolic composition of wines. The aim of this work was to study the effect of macerating enzymes on the polysaccharide and polyphenol composition of red wines. An increase of tannins and RG-II and a decrease of polysaccharides rich in arabinose and galactose have been observed in enzyme-treated wines. These wines have a higher colour intensity than the controls, which can be explained by an increase of pigments formed by reactions of anthocyanins with tannins. Effects were more or less pronounced depending on the vintage. For the first time, wine oligosaccharides have been isolated and characterized. They arise from the degradation of pectin smooth regions in the control wines and from pectin hairy regions in enzyme-treated wines. As enzymes modify wine polysaccharide and polyphenol composition, the evolution of these compounds have been studied in wine model solution so as to understand their reactivity and their impact on colour and on wine stability.
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https://tel.archives-ouvertes.fr/tel-00425504
Contributor : Marie-Agnès Ducasse <>
Submitted on : Wednesday, October 21, 2009 - 6:28:01 PM
Last modification on : Friday, November 13, 2020 - 3:30:13 AM
Long-term archiving on: : Tuesday, June 15, 2010 - 9:50:06 PM

Identifiers

  • HAL Id : tel-00425504, version 1
  • PRODINRA : 248832

Citation

Marie-Agnès Ducasse. IMPACT DES ENZYMES DE MACERATION SUR LA COMPOSITION EN POLYSACCHARIDES ET EN POLYPHENOLS DES VINS ROUGES – ETUDE DE L'EVOLUTION DE CES COMPOSES EN SOLUTION MODELE VIN.. Chimie. Université Montpellier II-Sciences et Techniques du Languedoc, 2009. Français. ⟨tel-00425504⟩

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