Asymmetrical flow field-flow fractionation with online multidetection is a viable tool to investigate colored red wine colloids

Over the past few decades, viticultural research has made numerous contributions which have made it possible to better understand the behavior of the vine as well as its response to the conditions imposed on it by the environment and agronomic practices. However, these results have only rarely been used in the practical management of vineyards because the research has been carried out using partial experimental models where reality is only represented by a few factors which are sometimes even made more complex by the introduction of elements foreign to the existing situation and difficult to apply to production (varieties, methods of cultivation, management techniques, etc.). To these reasons, one could add a low popularization of the results obtained, as well as the difficulty of implementing the scientific contributions, which does not allow the different production systems to fully express their potential. This limit of viticultural research can only be exceeded by the design of integrated projects designed directly on and for the territory. Indeed, only the integrated evaluation of a viticultural agro-system, which can be achieved through zoning, makes it possible to measure, or even attribute to each element of the system, the weight it exerts on the quality of the wine.

Dans le but d’améliorer la qualité et la typicité des vins de l’Appellation d’0rigine Contrôlée CAHORS, une étude a été réalisée afin de mettre en évidence l’adéquation Cépage-Terroir- Qualité du vin.
Selon la méthodologie proposée par MORLAT et ASSELIN (1992), neuf unités terroirs ont été déterminées. Sur chacune, des parcelles de référence homogènes quant au matériel végétal Cot ou Malbec ( cépage principal de cette appellation greffé sur S04, et aux méthodes culturales, ont été suivies au niveau agronomique et œnologique (GARCIA et al., 1996).

In grape berry pedicel, xylem hydraulic conductance can be impaired by blockage deposition in the lumen of xylem elements. However, the varietal difference of the interruptions has not yet been characterized. In this preliminary work, we utilized synchrotron x-ray computed microtomography experiments performed at MOGNO beamline (LNLS – Brazil) to identify possible blockage sites in natural grape pedicel xylem. For this, we imaged dehydrated pedicel’s stem portion from the Niagara Rosada variety in three different phenological stages (Pre-veraison (PreV), veraison (V) and post-veraison (PostV). The reconstructed tridimensional images with a voxel size of 1.16 µm were segmented for the identification of xylem vessel lumens. After analysing one pedicel stem per stage, we identified 658 vessels without occlusion throughout his axial plane and 41 in which we could identify possible interruptions.

With growing consumer interest in products without chemical additives, limiting the use of sulfites is a priority for the wine industry. Bioprotection is a biological alternative that avoids or reduces the risks of alterations that have a negative impact on the organoleptic quality of wines and, ultimately, on their acceptability to consumers. bioprotection can also provide a response to the risks of microbiological deviations, which are increased both by climate change and by the organization of harvesting operations, which increasingly include the use of multi-bins filled at the vine, exposing the harvest to sometimes high temperatures for longer periods of time.

Fruity notes play a key role in the consumer’s appreciation of Bordeaux red wines. If literature provides a lot of knowledge about the nature of volatile compounds involved in this fruity expression, the sensory phenomena involving these compounds in mixture still need to be explored. Considering previous sensory works about the impact of esters and some overripening compounds, the goal of this work was to study the implication of perceptual interactions involving red wine odorant compounds of diverse origins and described as potentially affecting fruity aromatic expression.