Selection of Yeast Strains for Making Red Dry Wines with Increased Antioxidant Activity from the Indigenous Grape Variety Krasnostop Zolotovsky

The subject of this paper was to search for and select yeast strains for wines from the Krasnostop Zolotovsky grape variety that contribute to an increased concentration of phenolic compounds with antioxidant activity. Additionally, the potential methyl-forming capacity of the yeasts and their influence on the organic acid composition in wines were investigated. The concentrations of coloring and phenolic compounds were determined by colorimetric methods. Coumaric, syringic, caffeic, and gallic acids were determined using high-performance liquid chromatography. The analysis of tartaric, malic, citric, succinic, lactic, and acetic acids in wines was performed by capillary electrophoresis. Methanol was determined by gas chromatography. Analysis of the conducted research showed a significant influence of yeast strains on the concentration of phenolic compounds, organic acids, and methyl alcohol in wines. Based on the research results, 7 yeast strains were selected, including 6 strains of S. cerevisiae (1-s-23, 1k-23, 5k-23, Y-4177, Y-4173, 437) and 1 strain of S. paradoxus (61F), which promote greater preservation of the complex of phenolic compounds during fermentation: the sum of phenolic compounds up to 38%, coloring compounds up to 25% of the initial content in the grape must. Strains 5-k-23, 61F, and Y-4173 were characterized by the best indicators among the selected 7 yeast strains according to the following parameters. Strains Y-4173 and 5-k-23 contributed to the formation of higher concentrations of phenolic acids, the sum of which amounted to 109 and 129 mg/dm3. Strains 437 and 61F provided higher concentrations of succinic acid up to 0.436 g/dm3. Strain 5-k-23 contributed to a higher level of malic acid up to 3.8 g/dm3. Also, strains 5-k-23 and Y-4173 were characterized by a low potential for methanol accumulation in wines, up to 15.8 mg/dm3. Thus, promising yeast strains were selected, providing higher concentrations of phenolic compounds with antioxidant activity and a low potential for methanol accumulation in the production of wines from the Krasnostop Zolotovsky variety.