Contribution to the aroma of white wines by controlled Torulaspora delbrueckii cultures in association with Saccharomyces cerevisiae

Although the positive role of non-Saccharomyces yeasts on the overall quality of wine is encouraging research into their oenological potential, current knowledge on the topic is still far from satisfactory. This work analyzes the contribution of starter cultures of Torulaspora delbrueckii, inoculated sequentially with Saccharomyces cerevisiae (multi-starter fermentation), on the fermentation and aromas of two different white style wines, i.e., dry and sweet wines. Chemical analysis of Soave and Chardonnay wines (dry wines) showed that multi-starter fermentation greatly affected the content of several important volatile compounds, including 2-phenylethanol, isoamyl acetate, fatty acid esters, C-4-C-10 fatty acids and vinylphenols. Moreover, strain-specific contributions have been shown by testing two different T. delbrueckii strains. Evidence of the positive impact of T. delbrueckii activity on wine quality was also demonstrated in Vino Santo, a sweet wine. Due to its low production of acetic acid, this non-Saccharomyces yeast is recommended for the fermentation of high sugar grapes. T. delbrueckii also influenced the content of different variety of chemical groups, including lactones. From a sensory perspective, all wines produced by multi-starter fermentation have greater aromatic intensity and complexity than wines resulting from a monoculture fermentation. These results emphasize the potential of employing T. delbrueckii, in association with S. cerevisiae, for the production of white wines of different styles with improved and enhanced flavour.