Use of Hansensiaspora uvarum and managing growth conditions increase polysaccharides and antioxidants content in yeast autolysates for winemaking

Yeast derivatives are winemaking additives generally obtained from Saccharomyces spp., commonly used as fermentation and wine quality enhancers. Even though they are widely used, the production process - from initial biomass to their final composition, is not standardized and often not specific for winemaking purposes. In the present study, biomass production was performed by applying different temperatures and agitation conditions, to assess their effect on the chemical composition of the resulting derivatives, using S. cerevisiae and H. uvarum as starting microorganisms. The application of shaking mostly affected the chemical composition of yeast derivatives, resulting in the highest mean concentration of amino acids (146 mg/g in S. cerevisiae), polysaccharides (370 mg/g in H. uvarum), and glutathione (about 85 μmol/g in S. cerevisiae). Derivatives obtained from H. uvarum were characterized by a non-negligible amount of glutathione (35.6 μmol/g - 53.1 μmol/g) and cysteine (12.7 μmol/g - 26.2 μmol/g), regardless of the growth conditions previously applied; only for this strain, reducing proteins linked to cell wall residues were detected. The results obtained suggest that the chemical composition of yeast derivatives may be managed during biomass production, also using specific strains, thus possibly obtaining products naturally rich in compounds of enological interest.