Non-Saccharomyces yeast derivatives: Characterization of novel potential bio-adjuvants for the winemaking process

Winemakers have access to a diverse range of commercially available Inactivated Dry Yeast Based products
(IDYB) from various companies and brand names. Among these, thermally inactivated dried yeasts (TIYs) are
utilized as yeast nutrients during alcoholic fermentation, aiding in the rehydration of active dry yeasts and
reducing ochratoxin A levels during wine maturation and clarification. While IDYB products are generally
derived from Saccharomyces spp., this study investigates into the biodiversity of those deriving from non-
Saccharomyces for potential applications in winemaking. For that S. cerevisiae and non-Saccharomyces TIYs were
produced, characterized for nitrogen and lipid content using FT-NIR spectroscopy, and applied in a wine-like
solution (WLS) for analyzing and quantifying released soluble compounds. The impact of TIYs on oxygen con-
sumption was also assessed. Non-Saccharomyces TIYs exhibited significant diversity in terms of cell lipid
composition, and amount, composition, and molecular weight of polysaccharides. Compared to that of
S. cerevisiae, non-Saccharomyces TIYs released notably higher protein amounts and nHPLC-MS/MS-based shotgun
proteomics highlighted the release of cytosolic proteins, as expected due to cell disruption during inactivation,
along with the presence of high molecular weight cell wall mannoproteins. Evaluation of antioxidant activity and
oxygen consumption demonstrated significant differences among TIYs, as well as variations in GSH and thiol
contents. The Principal Component Analysis (PCA) results suggest that oxygen consumption is more closely
linked to the lipid fraction rather than the glutathione (GSH) content in the TIYs. Overall, these findings imply
that the observed biodiversity of TIYs could have a significant impact on achieving specific oenological
objectives.