Valentina Martin, Laura Fariña, Eduardo Dellacassa, Albert Mas, 
and Francisco Carrau*  
*Universidad de la Republica, Enology and Fermentation Biotechnology Area, Av. General Flores 2124, Montevideo, Uruguay (fcarrau@fq.edu.uy)

During alcoholic fermentation, yeasts transform sugars present in the must primarily into ethanol, glycerol, and carbon dioxide, but also produce a set of compounds through secondary metabolism, including some aromatic and other compounds associated with wine color. Because these metabolites are important for the sensory quality of wines, it is important to understand and increase yeast diversity during fermentation to create unique wine profiles within a massive market. This study is an enological characterization of 11 strains of yeast identified as Hanseniaspora vineae, from which we have obtained positive contributions at the winery level. The yeast strains were evaluated to determine extracellular protease and β-glucosidase enzyme activities, fermentative capacity at low nitrogen levels, glycerol production, polysaccharide release, SO2 and alcohol resistance, formation of aromatic compounds, and cell lysis sensitivity. Fermentation products were evaluated to determine sensory properties related to consumer preferences. The results obtained enabled verification of the variability among strains of this species for accumulation of some aroma compounds, also demonstrated through other analyzed parameters. However, some key attributes were consistent among the 11 strains, such as high protease and β-glucosidase enzymatic activity, low production of short chain fatty acids and ethyl esters, and high production of decanoic acid compared to S. cerevisiae strains. The most outstanding characteristic of the species H. vineae was the production of benzenoids and phenylpropanoid esters (concentrations above two orders of magnitude) and ~4-times greater rate of cell lysis than S. cerevisiae strains, a key characteristic for aging wines on the lies. This behavior was reflected in the sensory evaluation, where all the fermentations per-formed with H. vineae were considered superior.

Funding Support: CSIC Universidad de la Republica ANII Uruguay