 IVES 9 IVES Conference Series 9 Assessment of wine non-Saccharomyces yeast strains as promising producers of glutathione

Assessment of wine non-Saccharomyces yeast strains as promising producers of glutathione

Abstract

AIM: Glutathione (GSH) is a non-protein thiol naturally present in grape berries and produced by yeasts during fermentation. It has a strong antioxidant activity, thus can be added during winemaking to limit the oxidative phenomena of wine, preserving sensory characteristics and stability, ultimately promoting a healthier product by reducing the need for SO₂ addition. A promising alternative approach could be the use of yeast starter cultures high-producers of this compound in situ, during the fermentation process, in substitution of external GSH addition. Since this activity in non-Saccharomyces yeasts is currently poorly investigated, the aim of this research was to evaluate the ability of three strains of non-Saccharomyces (NS) yeasts to produce GSH, both in synthetic media and in fresh grape must.

METHODS: Lachancea thermotolerans SOL13, Metschnikowia sp. FIANO12, and Starmerella bacillaris MALV45 were tested in single or sequential inoculations,with Saccharomyces cerevisiae EC1118, in synthetic grape juice (SGJ) or in Pinot Grigio grape must, under static conditions, or in a medium optimized for GSH production (MGSH) in agitation (200 rpm). GSH concentration was determined using the Glutathione Assay Kit (Sigma-Aldrich). Population dynamics was evaluated by plate count and biomass dry weight, and fermentation kinetics through weight loss measurement.

RESULTS: A variability in GSH production was found among individual strains and growth conditions. Metschnikowia sp. FIANO12 showed the highest intracellular accumulation of GSH when cultivated alone in both synthetic media, and, as expected, higher levels in the optimized MGSH than in SGJ (4.59 vs. 0.19 nmol GSH/mg cells, respectively). In wine, fermentations with S. bacillaris MALV45 had the highest concentration of intracellular GSH, but the lowest content of wine-dissolved GSH. The maximum level of extracellular GSH (21 mg/L) was obtained in the sequential fermentation with L. thermotolerans SOL13, a significant increase compared to the control singly inoculated with S. cerevisiae.

CONCLUSIONS:

This study highlights a new potential interesting feature of NS yeasts to positively modify wine composition. The tested native strains, with previously demonstrated interesting oenological traits, showed a good capacity to accumulate GSH and to increase the concentration of this antioxidant compound in wine. Thus, the strategy of multi-starter fermentation can be a valuable tool to achieve a lower input winemaking. Future investigations are needed to assess the long-term stability of wine made from multi-starter fermentations with NS yeasts producers of GSH.ACKNOWLEDGEMENTS: We thank Nicolò Bersani for laboratory assistance.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Renato L. Binati, Wilson J.F. LEMOS JUNIOR, Sandra TORRIANI

Department of Biotechnology, University of Verona, Italy, Department of Biotechnology, University of Verona, Italy, Department of Biotechnology, University of Verona, Italy

Contact the author

Keywords

Glutathione production, multi-starter fermentation, non-saccharomyces yeasts, saccharomycescerevisiae, winemaking, wine quality

Citation

An overview of wine sensory characterization: from classical descriptive analysis to the emergence of novel profiling techniques

The wine industry requires coexistence between tradition and innovation to meet consumers’ preferences. Sensory science allows the objective quantification of consumers’ understanding of a product and subjective feedback of consumer’s perception through acceptance or rejection of stimulus or even describing emotions evoked [1]. To measure sensations, emotions and liking, and their dynamics over time, time-intensity methods are crucial tools with growing interest in sensory science [2].

Exploring the influence of grapevine rootstock on yield components

Yield is an agronomic trait that is critical to the sustained success and profitability of the wine industry. In the context of global warming, overall yield tends to decrease. Rootstock has been identified as a relevant lever for adaptation to changing environmental conditions. The aims of this study are; i) to finely identify the components of the yield influenced by rootstock; ii) to characterise the rootstock × scion interaction; iii) to understand the trade-off between vigour and yield.

Juice carbon isotope discrimination is related to vine growth and fruit quality of Barossa Shiraz

Aim: Interactions between soil, climate and management that modulate vine growth, yield and grape composition are strongly defined by vine water availability and nutrient uptake during the season. Carbon isotope discrimination (δ13C) has been used as an integrative measurement of vine water availability during the season, with the potential to identify spatial variations of terroir in

Comparing the effects of vision, smell and taste in red wine quality judgments by experts: sensory cues, mental imagery and verbal representations as drivers of consensus in the multisensory space

In this study, we evaluated the contributions of vision, smell and taste to red wine quality judgments by expert wine tasters.

Integrated approach to grape stalks valorization: sustainable recovery of bioactive compounds and biofuel production

Grape stalks are a byproduct of the winemaking process and represent a valuable and inexpensive source of bioactive compounds. While their direct use in whole bunch fermentation is known, the majority of grape stalks are discarded, posing environmental and economic challenges.