Insights from selected ion flow tube mass spectrometry (SIFT-MS) and chemometrics applied to the quick discrimination of grapevine varieties

The aims of this study were to examine the effect of high sugar concentrations of must and copper residues on different commercial wine yeasts. Copper originating from pesticides has been known to inhibit yeast, but it’s effect on fermentation performance and VA production of different yeast strains had not been investigated in detail.

In a highly competitive worldwide market, a current challenge for the beverage sector is to diversify the range of products and to offer wines and spirits with typicity and character.

During alcoholic fermentation, wine yeasts generate a large variety of volatile metabolites, including acetate esters, ethyl fatty acid esters, higher alcohols, volatile fatty acids and volatile sulfur compounds that contribute to the aroma profile of wine. These molecules, refered as fermentative aromas, are the most abundant volatile compounds synthetized by yeasts and the metabolic pathways involved in their formation have been well characterized. Furthermore, other molecules with a major organoleptic impact may be produced during wine fermentation including terpene derivatives. However, little information is available on the contribution of yeasts to the formation of these molecules, in particular on their ability to synthethise de novo the terpens derivatives or to produce hydrolytic enzymes involved in the release of varietal precursors.

Grape typicity valorization can significantly enhance viticultural sector competitiveness to the extent that contributes to the development of a wine so distinctive and unique. This work leads to the characterization of the grapes through indicators expressing environmental effects.

Rotundone is the main aroma compound responsible for peppery notes in red wine. This positive and very potent molecule has an odor threshold of 8 ng/L in water and 16 ng/L in red wine. It has been detected in several grape varieties with some of the highest concentrations recorded in Syrah, Duras, Tardif and Noiret, an interspecific hybrid grown in the North-East of the USA. If several winemaking practices have been identified to lower rotundone in wine, up to date, no enological solution has proved its efficiency to maximize it. This means that efforts to produce high rotundone wines must be undertaken in vineyards. This work provides practical ways that can be used by winegrowers to modulate rotundone levels in their wines.

Aims: The aims of this study were (1) to measure the vertical temperature gradient in the vine canopy in parcels with different vineyard floor management practices and (2) to analyze the factors influencing this gradient. The objective was to investigate whether the increase of trunk height could be an adaptation strategy to reduce air temperature in the bunch zone in a context of climate change.