Effects of long-term drought stress on soil microbial communities from a Syrah cultivar vineyard

SO2 play a major role in wine stability and evolution during its aging and storage. Winemaking without SO2 is a big challenge for the winemakers since the lack of SO2 affects directly the wine chemical evolution such as the aromas compounds as well as the phenolic compounds. During the red wine aging, phenolic compounds such as anthocyanin, responsible of the red wine colour, and tannins, responsible of the mouthfeel organoleptic properties of wine, evolved quickly from the winemaking process to aging [1]. A lot of new interaction and molecules occurred lead by oxygen[2] thus the lack of SO2 will induce wine properties changes. Nowadays, the phenolic composition of the wine without added SO2 have not been clearly reported.

In the production of sparkling wines, during the second fermentation, mannoproteins are released by yeast autolysis, which affect the quality of the wines. The effect of mannoproteins has been extensively studied, and may affect aroma and foam quality. However, there are no studies on the effect of other polysaccharides such as those from grapes. Considering the large production of waste from the wine industry, it was proposed to obtain polysaccharide-rich extracts from some of these by-products[1].

Croatian viticulture is mainly based on native grapevine varieties susceptible to various diseases and pests, which leads to unsustainable use of large amounts of pesticides. The sustainable development of viticulture in the future will only be possible by increasing the resistance of the grapevine through the development of new resistant varieties. Breeding programs have been launched in the leading wine-growing countries to develop resistant varieties possessing high-quality levels. Native cultivars from Croatia are not included in the breeding programs of other countries.

Several Uruguayan wineries have begun to produce wines with minimal intervention, to increase the sustainability of their vineyards and wines. These wines are characterized by the minimum intervention in the management of the vineyard, its harvest, vinification, conservation and aging1,2. Sulfur dioxide (SO2) is not used or is used in reduced doses, although chitosan can be substituted or supplemented1. The objective of this research is to evaluate SO2 reduction or replacement options adapted to the production of Tannat red wines with minimal intervention. Vinification of the Tannat grapes with autochthonous yeasts (LN) was carried out during the 2023 vintage.

The wine industry is increasing the demand for indigenous yeasts adapted to the terroir to produce unique wines that reflect the distinctive characteristics of each region. In our group, we have identified and characterized 60 native yeast strains isolated from a vineyard in Maldonado-Uruguay, in which three strains stood out: Saccharomyces cerevisiae T193FS, Saturnispora diversa T191FS, and Starmerella bacillaris T193MS. Their oenological potential was evaluated at a semi-pilot scale in Tannat must vinification in the wine cellar to have a more precise and representative evaluation of the final product.