 IVES 9 IVES Conference Series 9 Exploring the resistance of non-Saccharomyces wine yeasts to dehydration-rehydration processes

Exploring the resistance of non-Saccharomyces wine yeasts to dehydration-rehydration processes

Abstract

AIM: The use of non-Saccharomyces (NS) yeasts in multi-starter fermentations with S. cerevisiae is a trend in the wine industry, but the number of strains commercially available in a powder formulation, such as active dry yeasts (ADY), is still limited. Considering that NS strains are bioresources which could boost innovation in the wine sector, efficient production of powder formulations is of utmost importance to valorise bioresources outside the laboratory environment.

METHODS: Three strains with high oenological potential, selected in previous studies, namely Lachancea thermotolerans DBT027, Metschnikowia sp. DBT012 and Starmerella bacillaris DBT045 were grown in a sterilized medium mainly constituted by grape juice with yeast assimilable nitrogen integration. Early stationary growth phase cultures were collected and suspended in 1% yeast extract, for powder production. The three prototype batches were rehydrated in tap water, to mimic winery conditions, for 15 minutes at four temperatures (20, 25, 30 and 35 ºC). Survival rates of yeasts were assessed before and after rehydration, and after storage at -20 ºC. The same powder NS yeasts were also in multi-starter fermentations in winery and their persistence was monitored.

RESULTS: The selected NS yeast strains were able to grow in the production medium with similar yields, and the powder formulation retained elevated cell viability (around 109-1010 cells/g). The optimal rehydration temperature was different for the three strains: Metschnikowia sp. DBT012 and L. thermotolerans DBT027 maintained higher survival at 35 ºC, while S. bacillaris DBT045 at 20 ºC, as could be expected considering the phenotypic characteristics of the species. Technological performances of the tested powder formulations were satisfactory, especially for DBT012, which was able to grow in grape must after inoculation and dominated over the indigenous microbiota.

CONCLUSIONS

The applied protocol for producing NS yeasts in the powder formulation was successful, as they retained high viability during rehydration and suitable activity when inoculated in must. Powder formulation guaranteed the conservation of the same batch for several comparative tests, bringing out their positive contribution to innovative winemaking biotechnologies. The ability to withstand a larger scale process of biomass production is essential for the exploitation of suitable non-Saccharomyces yeasts selected among a collection of yeast strains with proven oenological potential at laboratory scale. ACKNOWLEDGMENTS: Research developed in the framework of POR FESR 2014-2020 Regione del Veneto, project VIT-VIVE

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Giovanna Felis

Department of Biotechnology, University of Verona, Italy,Renato Leal BINATI, Dept. Biotechnology, University of Verona, Italy Eleonora TROIANO, Dept. Biotechnology, University of Verona, Italy Sandra TORRIANI, Dept. Biotechnology, University of Verona, Italy Marta TEBALDI, Microbion S.r.L. Italy Alessandro RONCADOR, Microbion S.r.L. Italy Fabio FRACCHETTI, Microbion S.r.L. Italy

Contact the author

Keywords

starter cultures, biomass production, dehydration, active dry yeasts

Citation

Elicitors used as a tool to increase stilbenes in grapes and wines

The economic importance of grapevine as a crop plant makes Vitis vinífera a good model system to study the improvement of the nutraceutical properties of food products (Vezulli et al. 2007). Stilbenes in general, and trans-resveratrol in particular, have been reported to be responsible for various beneficial effects. Resveratrol´s biological properties include antibacteria and antifungal effects, as well as cardioprotective, neuroprotective and anticâncer actions (Guerrero et al. 2010 ). Stilbenes can be induced by biotic and abiotic elicitors since they are phytoalexins (Bavaresco et al. 2001).

Consumer perception of wine bottle weight and its impact on sustainability

In the context of sustainability, this study evaluated consumer perception regarding the impact of glass bottle weight on wine valuation.

Elucidating vineyard site contributions to key sensory molecules: Identification of correlations between elemental composition and volatile aroma profile of site-specific Pinot noir wines

The reproducibility of elemental profile in wines produced across multiple vintages has been previously reported using grapes from a single scion clone of Vitis vinifera L. cv. Pinot noir. The grapevines were grown on fourteen different vineyard sites, from Oregon to southern California in the U.S.A., which span distances from approximately hundreds of meters to 1450 km, while elevations range from near sea level to nearly 500 m. In addition, sensorial (i.e. aroma, taste, and mouthfeel) and chemical (i.e. polyphenolic and volatile) differences across the different vineyard sites have also been observed among these wines at two aging time points. While strong evidence exists to support that grapes grown in different regions can produce wines with unique chemical and sensorial profiles, even when a single clone is used, the understanding of growing site characteristics that result in this reproducible differentiation continues to emerge. One hypothesis is that the elemental profile that a vineyard site imparts to the grape berries and the resulting wine is an important contributor to this differentiation in chemistry and sensory of wines. For example, various classes of enzymes that catalyze the formation of key aroma compounds or their precursors require specific metals. In this work, we begin to report correlations between elemental and volatile aroma profiles of site-specific Pinot noir wines, made under standardized winemaking conditions, that have been previously shown to be distinguished separately by these chemical analyses.

Synergistic effect of fumaric acid and chitosan on the inhibition of malolactic fermentation

During wine storage and aging, microorganisms capable of degrading malic acid in an undesirable manner can proliferate.

StartupLab and HackaVitis: open innovation and technology transfer in the wine sector

The study analyzes a set of open innovation actions promoted by the innovation environments of the Instituto Federal do Rio Grande do Sul (IFRS), in cooperation with entities, companies in the sector and the Department of Innovation, Science and Technology of Rio Grande do Sul.