“Vinhos de mesa” et oenophilie : quand les caractéristiques organoleptiques des cépages américains empêchent l’intégration des consommateurs à l’univers de l’appréciation esthétique

Monoterpenes are important aroma compounds in white wines. Many monoterpenes are chiral and the chiral forms have different aroma qualities.

In sparkling winemaking several yeasts can be used to perform the primary alcoholic fermentation that leads to the elaboration of the base wine. However, only a few Saccharomyces cerevisiae yeast strains are regularly used for the secondary in-bottle alcoholic fermentation 1. Recently, advances in yeast development programs have resulted in new breeds of interspecific wine yeast hybrids that ferment efficiently while producing novel flavours and aromas 2. In this work, sparkling wines produced using interspecific yeast hybrids for the secondary in-bottle alcoholic fermentation have been chemically and sensorially characterized.METHODS: Three commercial English base wines have been prepared for secondary in-bottle alcoholic fermentation with different yeast strains, including two commercial and several novel interspecific hybrids derived from Saccharomyces species not traditionally used in sparkling winemaking. After 12 months of lees ageing, the 14 wines produced were analysed for their chemical and macromolecular composition 3,4, phenolic profile 5, foaming and viscosity properties [6]. The analytical data were supplemented with a sensory analysis.

Botrytis cinerea (Bc) is one of the main pathogens affecting the cultivated grapevine. A key role in grapevine tissue colonization is played by cell wall (CW) remodeling driven by CW Modifying Enzymes (CWMEs), expressed both by the host and the pathogen. Their action can impact CW integrity and trigger specific immune signaling, thus influencing Bc infection outcome. To further characterize the role of the CW in the grapevine response to Bc, two contrasting genotypes in their resistance to the fungus were artificially inoculated at full bloom. RNA-seq analysis and biochemical characterization of the CW and its modification in samples collected at 24 hours post-inoculation highlighted significant differences between genotypes.

Measurement of carbon isotope discrimination in berry juice sugars at maturity (δ13C) provides an integrated assessment of water use efficiency (WUE) during the period of berry ripening, and when collected over multiple seasons can be used as an indication of drought stress response. Berry juice δ13C measurements were carried out on 48 different varieties planted in a common garden experiment in Bordeaux, France from 2014 through 2021 and were paired with midday and predawn leaf water potential measurements on the same vines in a subset of six varieties. The aim was to discriminate a large panel of varieties based on their stomatal behaviour and potentially identify hydraulic traits characterizing drought tolerance by comparing δ13C and hydroscapes (the visualisation of plant stomatal behaviour as a response to predawn water potential). Cluster analysis found that δ13C values are likely affected by the differing phenology of each variety, resulting in berry ripening of different varieties taking place under different stress conditions within the same year. We accounted for these phenological differences and found that cluster analysis based on specific δ13C metrics created a classification of varieties that corresponds well to our current empirical understanding of their relative drought tolerances. In addition, we analysed the water potential regulation of the subset of six varieties (using the hydroscape approach) and found that it was well correlated with some δ13C metrics. Surprisingly, a variety’s water potential regulation (specifically its minimum critical leaf water potential under water deficit) was strongly correlated to δ13C values under well-watered conditions, suggesting that base WUE may have a stronger impact on drought tolerance than WUE under water deficit. These results give strong insights on the innate WUE of a very large panel of varieties and suggest that studies of drought tolerance should include traits expressed under non-limiting conditions.

Egri Bikavér (Bull’s Blood) is one of the most remarkable Hungarian red wines on inland and foreign markets as well. From the end of the 70’s the quality of Egri Bikavér was decreasing continually due to mass production. The concept of production of quality wines became general in the mid 90’s again and it resulted in a new Origin Control System, for the first time that of Egri Bikavér in Hungary.