CONTRIBUTION TO THE IDENTIFICATION OF LINKS BETWEEN GRAPE RAW MATERIAL AND THE EXTRACTION OF PHENOLIC COMPOUNDS IN RED WINEMAKING - IMPACT OF GRAPE VARIETY AND MATURITY

Facing the diversity and heterogeneity of wine grapes in order to optimize the winemaking process is a complicated task. In red wines, polyphenol extraction goes along with reactivity and structural changes of grapes that affect their qualitative properties (colour, astringency). In practice, it is often difficult to find a simple and direct link between the classical enological parameters of musts, like composition in sugar and in organic acids, and the wine polyphenol composition at the end of vinification. This is probably related to differences in applied winemaking processes, like the ones during maceration, which are very variable (temperature, skin contact, yeast strains etc.). The objective of this project is to contribute to the development of new approaches in characterizing the heterogeneity of raw material and wines in order to establish, for given process conditions, links between their composition and finally identify the most relevant markers.