Les études d’impact du climat sur la vigne nécessite de descendre à des échelles très fines car les facteurs climatiques sont tributaires de la topographie, la végétation, les expositions … Dans le cadre du programme ANR-JC Terviclim, 22 capteurs ont été installés dans les vignobles des Coteaux du Layon afin de caractériser le climat particulier de ces terroirs. L’analyse des températures montre de fortes disparités entre les data loggers et pourtant situés parfois sur les mêmes parcelles ou sur des parcelles voisines. Les indices bioclimatiques tels les degrés jours sont également contrastés suivant la situation des capteurs sur les coteaux.

Non-Saccharomyces yeasts have been associated, for many years, with challenging alcoholic fermentation processes. However, during the last decade the use of non-Saccharomyces yeasts in wine production has become increasingly widespread due to the advantages they can offer in mixed inoculations with Saccharomyces cerevisiae (Sc). In this respect, Hanseniaspora vineae (Hv), in synergy with Saccharomyces spp, represents an interesting opportunity to impart a positive contribution to the aroma complexity of wines. In fact, it is a well-known producer of pleasant esters, such as 2-phenylethyl acetate. This study compares the performances of Hv (strain Hv-205) in sequential inoculation modality to Sc in three Chardonnay musts for base sparkling wine production. No significant differences were observed in basic chemical parameters between wines except for titratable acidity, with a significantly decrease (up to 1.5 g/L) in Hv processes due to malic acid degradation. The analysis of the aroma compounds revealed remarkable differences in concentration of volatile metabolites, among others up to 37-fold increase of 2-phenylethyl acetate. In contrast, lower concentration of its alcohol were detected, suggesting higher acetylation activity by Hv.

AIM: Recent studies on yeast ecology of non-oenological niches have highlighted the ability of some Saccharomyces cerevisiae yeasts to ferment grape must [1]

In this study for the first time, eight natural stilbenes (trans-resveratrol, trans-piceid, cis-piceid, trans-astringin, trans-piceatannol, (+)-trans-s-viniferin, pallidol and hopeaphenol) isolated and purified from Vitis vinifera, were simultaneously separated and analysed within 5 mn by ultra high pressure liquid chromatography coupled with photodiode array detection.

The aim of this work was to analyze the variability in grape composition of the Tempranillo cultivar related to climatic conditions, in La Mancha Designation of Origin. Grape composition (sugar content, total acidity, pH, malic acid, and total and extractable anthocyanins) recorded during ripening, were analysed for the period 2000-2019. The weather conditions at daily time scale, recorded during the same period, were also evaluated. The relationships between grape parameters with climatic variables related to temperature and to water deficits, referring different periods between phenological events along the growing cycle, were evaluated using regression analysis. High variability in grape composition was observed in the period analysed. Total acidity varied between 3.7 and 7.3 gL-1 while malic acid varied between 1.2 and 4 gL-1. The extractable anthocyanins ranged between 526 and 972 mgL-1, and total anthocyanins ranged between 922 and 1388 mgL-1, being the lowest values recorded in the hottest year (2017). Total acidity decreased 0.77 gL-1 for an increase of 100 GDD, while malic acid decrease in 0.42 gL-1 for the same GDD increase, being the period between veraison and harvest the one that seemed to have higher influence on acidity. In addition, it was confirmed that increasing water deficits decreased acidity. Total and extractable anthocyanins increased in about 210 and 105 mgL-1, respectively, with an increase of 100 GDD from veraison to harvest, and the increase in water deficits favour the increase of anthocyanins, both total and extractable anthocyanins. Total and extractable anthocyanins concentration increased in 35 and 22 mgL-1 per an increase of 10 mm in the water deficit. These results can be of interest to understand the potential changes that grapes composition may suffer under future warmer climates.