Résumé
The diversification of the supply, in terms of typicality and sensory complexity of fermented beverages (wine, cognac, whisky ...), is an option favored by producers to establish themselves in a highly competitive market. Indeed, the development of new products showing original sensory profiles must meet the consumers’ new expectations, who are looking for high-quality wines and spirits, with a strong aromatic character. These notes can be brought by compounds belonging to different chemical groups, and derived from different pathways of the yeast’s metabolism. Some of these compounds are well-known (higher alcohols, acetate esters, ...), but other volatile molecules are more unusual : terpenes, lactones and benzene derived molecules are some examples of those unusual compounds. In this context, the first step of the work was to study the fermentation ability of 54 non-Saccharomyces and 40 Saccharomyces yeast strains, isolated from grape juices. The fermentations were carried out in enological conditions, at 24°C. Interestingly, some of the non-Saccharomyces strains managed to consume more than 80% of the total sugars present in the must. The second part of this work was to study the production of volatile molecules by the strains during the fermentation, using GC-MS. Similar to the fermentation aspects, the volatile profiles of the different strains were quite different, which corroborated the high diversity of the non-Saccharomyces yeasts. Furthermore, some strains produced unusual aromas. This work can highlight the potential of some non-Saccharomycesyeast strains –even in pure cultures- for winemaking.