Application of grape pomace and stem extracts on Vitis vinifera L. cv. Monastrell: Increased stilbene content of grapes and wines

The definition of the term “quality” in sensory evaluation of food products does not seem to be consensual. Descriptive or liking methods are generally used to differentiate between wines (Lawless et al., 1997). Nevertheless, quality evaluation of a product such as wine can also relate to emotional aspects. As exposed by Costell (2002), product quality is defined as an integrated impression, like acceptability, pleasure, or emotional experiences during tasting. According to the ‘modality appropriateness’ hypothesis which predicts that wine tasters weigh the most suitable sensory inputs for a specific assess- ment (Freides, 1974; Welch & Warren, 1980), the nature of the quality definitions may modulate sensory influences.

The use of the term bioprotection in winemaking refers to the use of non-chemical methods to prevent the development of undesirable microorganisms (yeasts and/or bacteria). The reason for studying this method is mainly as a natural alternative to the addition of sulfites during the pre-fermentation stages. In winemaking, the addition of s02 has multiple functions, the main ones being antiseptic and antioxidant power.

The use of resistant varieties is a long-term but promising solution to reduce chemical input in viticulture. Several important breeding programs in Europe and abroad are now releasing a range of new hybrids performing well regarding fungi susceptibility and producing good quality wines. Unfortunately, insufficient attention is paid by the breeders to the adaptation of these varieties to climatic changes, notably to the increased climatic demand and water deficit (WD). Thus, prior to the adoption of such varieties by the wine industry in Mediterranean regions, there is a need to consider their suitability to WD. This study aimed to characterize the different drought-strategies adopted by 6 new resistant varieties selected by INRAE in comparison to Syrah. To allow the assessment of long-term impacts of WD, field-grown vines were exposed to contrasted WD from 2018 to 2021 under a semi-arid Mediterranean climate. A gradient of WD was applied in the field and controlled through plant measurements at the single plant level. Grape development was non-destructively monitored to determine the arrest of berry phloem unloading. The impacts of WD on berry composition, including water, primary metabolites (sugars, organic acids), secondary metabolites (anthocyanins, thiols precursors) and main cations contents, were assessed at this specific stage. Results showed different varietal responses during the year and inter-annual acclimation in terms of plant water use efficiency, biomass accumulation, as well as yield components and berry composition. WD differentially reduced the accumulation of primary metabolites at plant and berry levels, but it little changed their concentrations in the fruits at the ripe stage. Moreover, WD differentially impacted the accumulation of secondary metabolites and major cations between the varieties. In the talk, we’ll present the main results regarding the WD impacts on fruit metabolites and enlarge the reflection about the practical assessment of the grapevine acclimation to WD.

Cet article propose la formalisation d’un modèle paramétrique pour représenter l’accumulation des sucres dans les baies de raisin durant la maturation. Le test de ce modèle sur des jeux de données réels a permis de valider l’approche proposée. Une seconde partie est axée sur l’adaptation de la méthode pour permettre la simulation du comportement du millésime en cours dès les premiers relevés de maturité. Ce travail possède de multiples applications dans le domaine de l’aide à la décision.

Protecting table grape vineyards with white hail‐nets is a common practice in Southern Italy. Hail‐nets result in shading effects of 10‐20 %, depending on their density