Fermentation of must from black grapes: wine starter role in natural antioxidant power evolution

Wine antioxidant activity varies considerably depending on grape cultivar, environmental factors in vineyard, and wine processing techniques. Only a few studies have evaluated the effect of winemaking techniques and yeasts on the antioxidant activity of wines. Among the different methodologies proposed to assess the antioxidant activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) method can be recommended; 50% of the total radical scavenging activity in red wines is attributed to polymeric phenolic compounds.The aim of this work was to study yeast strain variability to confer high antioxidant activity to red wine using 5 hybrid strains of Saccharomyces cerevisiae, obtained during the PRIN 2007 project: “Wine strain improvement strategies to enhance red wine safety based on parietal adsorption activity”.Regarding the wine antioxidant activity, the 5 hybrids: RC029A-1DxRE078C-1C (H1), RC029B-1CxRE078C-1C(H2), RC029B-1CxRC039C-1C(H3), RC029B-1CxNA093B-1C(H4), and RE049B-1AxNA093B-1C(H5) were compared to the commercial strain S. cerevisiae F15 Zymaflore (Laffort Œnologie), selected for red wine production. Winemaking trials using black grapes from the Calabrian cultivars Magliocco, Gaglioppo, Nerello calabrese and Malvasia nera were performed. Grapes were destemmed, crushed and inoculated with 5% of 48-h precultures of each strain. Wines were analysed for: ethanol content, colour, colour intensity and tint, Folin-Ciocalteu index, % of DPPH inactivation, and total ascorbic acid equivalents (TAA) expressed as mg/mL.Results demonstrate that yeast significantly modifies wine antioxidant activity in different ways according to the grape cultivar used. In detail, for the Magliocco cultivar the TAA content of the wine produced using the F15 Zymaflore strain is significantly higher than the TAA content of the wines produced using 4 out the 5 hybrids. Regarding the Gaglioppo cultivar, results vary between the two wineries involved in the study. In the first-one, no hybrid produces wines with a TAA content significantly different from wine produced using the F15 Zymaflore strain. In the second-one, 4 out the 5 wines produced using the hybrids exhibit a TAA content significantly lower than in wine produced using the F15 Zymaflore strain. For the Nerello calabrese cultivar the TAA content of the wines produced using the H3 and H4 strains are significantly higher than in the wine produced using F15 Zymaflore strain. For the Malvasia nera cultivar the TAA content of the wines produced using the H3 and H5 strains are significantly higher than in the wine produced using F15 Zymaflore strain; in contrast, the TAA content of the wine produced using the H2 strain is significantly lower than in the wine produced using F15 Zymaflore strain.In conclusion, it seems advantageous to select yeast starter cultures for winemaking in function of their positive correlation with total antioxidant activity.This research was supported by PRIN 2007 “Wine strain improvement strategies to enhance red wine safety based on parietal adsorption activity” and by Calabria Region, Research Fund APQ, Action 2, Laboratories LIPAC, QUASIORA, and AGROMATER (A. Caridi). The authors would like to thank: Azienda Agrituristica Contessa, Azienda Vinicola Malaspina Consolato, Cantina Caparra & Siciliani, Azienda Agricola Murace Cosimo, Azienda Agricola Fratelli Zagarella for their kind collaboration and participation in this study.