Évolution de la surmaturation du cépage Chenin dans différents terroirs des Coteaux du Layon en relation avec les variables agroviticoles

L’extraction phénolique au cours de la fermentation à partir de vendanges de différents degrees de maturité du cépage Syrah/R99 a été etudiée. Cette travail fait parti d’un projet focalisé sur la qualité du raisin et des vins obtenus au cours du millésime 2002. Les vignes sont situées à Stellenbosch (Afrique du Sud) sur un sol Glenrose

Wineries may randomly reject fruit from vineyards near wild fires exposed to smoke. It is difficult to determine if fruit has been compromised in quality when exposed to smoke

Water scarcity, high air temperatures, high vapor pressure deficit, and increasing frequency and intensity of extreme climatic events, namely heat waves, exert huge pressure on viticulture, as is the case of Mediterranean climates. Therefore, farmers rely more and more on irrigation to overcome these constraints. Deficit irrigation is a proved strategy to optimize irrigation efficiency and wine quality. The present study intends to demonstrate the application of precision techniques, namely remote sensing derived vegetation indices (VI) and an open source software, SIMDualKc, to compute crop evapotranspiration using the dual crop coefficient approach (Kcb + Ke), for deficit irrigation management.

Infection of the grapes with Botrytis cinerea has a tremendous impact on the resulting crop yield and quality. Well-known problems that are associated with B. cinerea are specific off-flavors, poor filterability, and brownish color in white wines. The development of a B. cinerea infection strongly depends on weather conditions and is highly variable through different vintages. Typical control measures include defoliation and the use of fungicides, which involves high personnel and material costs. They also involve a great risk, especially since the effectiveness and time point of these treatments are difficult to predict.

In addition to aroma compounds also protein composition strongly influences the quality of wines. Proteins of wine derive mainly from the plant Vitis vinifera and may be influenced by abiotic stress as well as fermentation conditions or fining. Additionally, fungal infections can affect the protein content as well by introducing fungal proteins or affecting grape protein composition. An infection of the vine with the plant pathogenic fungus Botrytis (B.) cinerea was shown to cause a degradation of proteins in the resulting wine. Moreover, it influences the foaming properties in sparkling wine.