L’évolution des Appellations d’Origine aux Etats-Unis

The objective of this study is to review the scientific evidences and to advance into the knowledge of the molecular mechanisms of astringency. Astringency has been described as the drying, roughing and puckering sensation perceived when some food and beverages are tasted (1). The main, but possibly not the only, mechanism for the astringency is the precipitation of salivary proteins (2,3). Between phenolic compounds found in red wines, flavan-3-ols are the group usually related to the development of this sensation. Other compounds, phenolic or not, like anthocyanins, polysaccharides and mannoproteins could act modifying or modulating astringency perception by hindering the interaction between flavanols and salivary proteins either because of their interaction with the flavanols or because of their interaction with the salivary proteins.

In order for a spatialized gestion of wine-producing areas, delineation of viticultural zones is needed. Viticultural zoning according to qualitative expression of varieties is a great concern

Mannoproteins are released at the end of alcoholic fermentation due to yeast autolysis [1]. It has been described a positive effect of these molecules on lactic acid bacteria growth [2]. The main objective of this work was the characterization of different mannoproteins extracted from active dry yeast (ADY) and the assessment of their effect on Oenococcus oeni and malolactic fermentation (MLF).

Apart from pro(antho)cyanidins and tannins, other phenolic compounds in wine or grapes have been shown to interact with salivary proteins and may contribute to overall sensory in-mouth sensations [1, 2]. Anthocyanins are the dominant phenolics in red wine and grape skin [3] , so it is expected that they come into contact and interact with salivary proteins after ingestion.

For the chemical characterization of Aszu wines from Tokaj region our aim is to develop a biochemical method which is related to Botrytis cinerea.