Macrowine 2021
IVES 9 IVES Conference Series 9 Wine yeast species show strong inter- and intra-specific variability in their sensitivity to uv-c radiation

Wine yeast species show strong inter- and intra-specific variability in their sensitivity to uv-c radiation

Abstract

While the trend in winemaking is toward reducing the inputs and especially sulphites, the development of While the trend in winemaking is toward reducing the inputs and especially sulphites, the development of innovative process to ensure microbial stabilization is a relevant topic for the industry. UV-C process is a non-thermal technique widely used for food preservation. In this study, we evaluated the relative sensitivity to UV-C of various wine related yeast species. A first approach was conducted using a drop-platted system. 147 strains distributed amongst fourteen yeast species related to wine environment were plated on Petri dishes (with 3 different drop densities) and exposed to six increasing UV-C doses. An important variability in UV-C response was observed at the interspecific level. Cellar resident species, which are mainly associated with wine spoilage, expressed higher sensitivity to UV-C than vineyard resident species. A focus on B. bruxellensis species with 104 screened strains highlighted an important effect of the UV-C, with intra-specific variation. The impact of this intra-specific variation of UV-C sensitivity on wine treatment efficiency was then studied. Six B. bruxellensis strains(including two sulphites resistant strains) from three different genetic groups were separately inoculated in red wine Those inoculated wines were then treated in our home-made UV-C pilot which allows the continuous treatment of liquids at 200 L.h-1. 4968 J.L-1 were sufficient to achieve 4.70 and 5.17 log10 reduction for both sulphites resistant strains, resulting in populations lower than 1 CFU.mL-1 after UV-C treatment. 6624 J.L-1 were required to achieve the same level of population (<1CFU.mL-1) for 3 other strains. This treatment was not sufficient to achieve the same result only for one strain. These results highlight the potential of UV-C utilisation against wine yeast spoiler at cellar scale even in highly absorbent wine (α254 = 31.6 cm-1). They also show that intraspecific variability (in addition to the already known interspecific variability) may have an effect on the required doses for the microbiological stabilization of wines.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Etienne Pilard

PhD student at ISVV,Jules HARROUARD PhD student at ISVV Warren ALBERTIN assistant professor at ISVV Cécile MIOT-SERTIER technician at ISVV Remy GHIDOSSI professor at ISVV

Contact the author

Keywords

UV-C treatment ; Wine shelf-life ; Brettanomyces bruxellensis

Citation

Related articles…

Terroir analysis and its complexity

Terroir is not only a geographical site, but it is a more complex concept able to express the “collective knowledge of the interactions” between the environment and the vines mediated through human action and “providing distinctive characteristics” to the final product (OIV 2010). It is often treated and accepted as a “black box”, in which the relationships between wine and its origin have not been clearly explained. Nevertheless, it is well known that terroir expression is strongly dependent on the physical environment, and in particular on the interaction between soil-plant and atmosphere system, which influences the grapevine responses, grapes composition and wine quality. The Terroir studying and mapping are based on viticultural zoning procedures, obtained with different levels of know-how, at different spatial and temporal scales, empiricism and complexity in the description of involved bio-physical processes, and integrating or not the multidisciplinary nature of the terroir. The scientific understanding of the mechanisms ruling both the vineyard variability and the quality of grapes is one of the most important scientific focuses of terroir research. In fact, this know-how is crucial for supporting the analysis of climate change impacts on terroir resilience, identifying new promised lands for viticulture, and driving vineyard management toward a target oenological goal. In this contribution, an overview of the last findings in terroir studies and approaches will be shown with special attention to the terroir resilience analysis to climate change, facing the use and abuse of terroir concept and new technology able to support it and identifying the terroir zones.

Using a grape compositional model to predict harvest time and influence wine style

Linking wine composition to fruit composition is difficult due to the numerous biochemical pathways and substrate transformations that occur during fermentation

Evaluation of vineyards, fruit and wine affected by wild fire smoke

Wineries may randomly reject fruit from vineyards near wild fires exposed to smoke. It is difficult to determine if fruit has been compromised in quality when exposed to smoke

WineMetrics: A new approach to unveil the “wine-like aroma” chemical feature

“The Human being has an excellent ability to detect and discriminate odors but typically has great difficulty in identifying specific odorants”(1). Furthermore, “from a cognitive point of view the mechanism used to judge wines is closer to pattern recognition than descriptive analysis.” Therefore, when one wants to reveal the volatile “wine-like feature” pattern recognition techniques are required. Sensomics is one of the most recent “omics”, i.e. a holistic perspective of a complex system, which deals with the description of substances originated from microorganism metabolism that are “active” to human senses (2). Depicting the relevant volatile fraction in wines has been an ongoing task in recent decades to which several research groups have allocated important resources. The most common strategy has been the “target approach” in order to identify the “key odorants” for a given wine varietal.

Quantitative assessment of must composition using benchtop NMR spectroscopy: comparative evaluation with FTIR and validation by reference

The foundation of wine production lies in the use of high-quality grapes. To produce wines that meet the highest standards, a fast and reliable analytical assessment of grape quality is essential. Many wineries currently employ Fourier-Transform Middle-Infrared Spectroscopy (FTIR) for this purpose.