YEAST LEES OBTAINED AFTER STARMERELLA BACILLARIS FERMENTATION AS A SOURCE OF POTENTIAL COMPOUNDS TO IMPROVE SUSTAINABILITY IN WINE- MAKING
The yeast residue left over after wine-making, known as wine yeast lees, is a source of various compounds that are of interest for wine and food industry. In winemaking, yeast-derived glycocompounds and proteins represent an example of circular economy approach since they have been proven to reduce the need for bentonite and animal-based fining agents. This leads to a reduced environmental impact in the stabilization and fining processes in winemaking. (de Iseppi et al., 2020, 2021). The recent discovery of the wine-making potential of the non-Saccharomyces yeast Starmerella bacillaris has sparked new interest in the use of this species for lees valorization, due to its potential difference in cellular composition from the conventional wine yeast Saccharomyces cerevisiae (Lemos et al., 2016; Moreira et al., 2022). To investigate the cell compositions of yeasts present in the lees, 5 strains of Starmerella bacillaris and Saccharomyces cerevisiae were grown in winemaking conditions. After cells harvesting, different cell components (from cell wall and cytoplasm) were separated by means of cell breakage with glass beads and further enzymatic or chemical treatments. The fractions were characterized in respect of sugar and protein content, by means of HPLC and SDS-PAGE separation, evidencing differences between the species in terms of mannose, glucose and N-acetylglucosamine profile, protein content and protein molecular size. To investigate the practical implications on winemaking, the fractions were tested on wine as agents of protein stabilization and fining. This allowed to make some preliminary evaluation about the potential applications of Starmerella bacillaris as yeast derivatives, obtained from yeast lees.
Issue: OENO Macrowine 2023
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non-saccharomyces yeast, Yeast cell walls, Yeast protein extracts, Yeast polysaccharides