Optimization of a tool to determine the oxygen avidity of a wine through the kinetics of consumption by its phenolic and aromatic fractions (PAFs)

Wine aroma is influenced by several viticultural and oenological factors. In this study we used experimental wine making in a full factorial design to determine the impact of grapevine age, must turbidity, and yeast strain on the aroma of Vitis vinifera L. cv. Riesling wines. A recently developed, non-targeted SPME-GC-MS fingerprinting approach for wine volatiles was used. This approach includes the segmentation and mathematical transformation of chromatograms in combination with Parallel Factor Analysis (PARAFAC) and subsequent deconvolution of important chromatogram segments.

STICS est un modèle de culture développé à l’INRA (France) depuis 1996. Il simule les bilans de carbone, d’eau et d’azote dans le système culture-sol, piloté par des données climatiques journaliéres. Il calcule à la fois des variables agricoles (rendement en quantité et qualité) et environnementales (pertes en eau et en azote). Une des originalités de STICS est son adaptabilité à de nombreuses cultures (herbacées, ligneuses, annuelles, pérennes) rendue possible par le choix de paramètres génériques et d’options de formalismes. Le travail présenté traite, dans un premier temps, des spécificités de STICS pour la vigne en terme de bilan trophique, de fonctionnement énergétique et hydrique et d’estimation des teneurs en sucre en en eau du raisin. Nous montrons ensuite diverses sorties du modèle qui permettent de caractériser des terroirs du vignoble des Côtes du Rhône.

The grape variety Gewürztraminer is known to be affected by two physiological disorders namely berry shrivel and bunch stem necrosis. During the season 2014 we noticed a new symptomatology type of ripening disorder on the variety. The new symptom showed not all berries fallowing the normal maturation stages, but single berries remaining at a soft but green stage till harvest. The broad distribution of these so called “green berries” symptoms in different production sites of our region, caused huge damage due to the difficulty of eliminating single berries per bunch before harvesting. Therefore, the Research Centre Laimburg began to investigate the reasons and origins of this new symptom. This work shows the results of first attempts to find causes for the symptom as well as the resulting approach to mitigate symptoms. Applications of magnesium leaf fertilizer showed first promising results against this putative disorder. To study the causal effect of the green berries 30 symptomatic vineyards in 2014 have been selected for a monitoring during the season 2016. To evaluate the foliar nutrient treatment two vineyards have been selected for application of magnesium sulfate and magnesium chloride. Leaf and berry nutrient analysis, as well as the main quality parameters during ripening have been performed. As soon as “green berries” symptoms appeared, incidence and severity have been evaluated. Most of the symptomatic vineyards of the 2016 monitoring showed light to clear magnesium deficit symptoms on their foliage. Only during the seasons 2020 and 2021 “green berries” symptoms could be found in the leaf fertilizer treatment vineyards. Both seasons showed a significant effect of the magnesium treatments to reduce the incidence and severity of the symptom. It seems that the appearance of the “green berries” symptom on Gewürztraminer is correlated to a disturbed uptake of magnesium of the vines.

Cet exposé présente une caractérisation générale de la Région Délimitée du Douro (RDD), productrice des appellations Porto (vins généreux), et Douro pour des vins de qualité VQPRD.

The phenological stage of the grapevine (Vitis vinifera L.) represents a fundamental element in vineyard management, since it determines key practices such as fertilization, irrigation, phytosanitary interventions and optimal harvest time (Mullins et al., 1992).