La hiérarchisation des Coteaux du Languedoc: une application concrète du zonage vitivinicole

The browning index (BI), based on the absorbance at 420 nm, is a common oxidation marker in white wines, typically measured after thermal stress (50–60 °C for 5 up to 12 days) in air-saturated wines.

Les cycles journaliers du potentiel hydrique foliaire (Ψl) ont été établis toutes les heures, pour différents stades phénologiques, sur deux localités et en fonction de différentes mesures de la température de l’air et du déficit en pression de vapeur (VPD). De faibles valeurs pour ces 2 paramètres ont été enregistrées tout au long de la saison à

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.

Astringency is an important red wine quality attribute, which can be measured both chemically and sensorially. The use of tannin activity shows potential as a valuable chemical measurement in understanding red wine mouthfeel properties such as astringency and bitterness, which is also affected by tannin structural factors, in addition to matrix effects. Tannin activity is defined as the enthalpy of interaction between tannins and a hydrophobic surface. Studies involving tannin activity have been performed since the early 2010’s, but chemosensory studies used to evaluate how structure-activity relationships change across multiple, consecutive vintages are limited. The aim of this study is to investigate how tannin activity may be linked to red wine mouthfeel, and how all these variables may change according to wine age.

Phenolic compounds are secondary metabolites of grapes. Plants produce a wide variety of this type of metabolites through diverse biosynthesis pathways and their production is sometimes a response to external stimuli, either environmental or biotic stresses. Some of them may act as chemical defenses against pathogens or herbivores and their synthesis is increased when the attack exists. However, it is remarkable that the synthesis of these interesting compounds can be activated even when the stimulus is not present, with the use of elicitors. These are substances that when applied exogenously trigger the biosynthetic pathways conducting to the synthesis of these defense compounds.