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…

How does aromatic composition of red wines, resulting from varieties adapted to climate change, modulate fruity aroma?

One of the major issues for the wine sector is the impact of climate change linked to the increasing temperatures which affects physicochemical parameters of the grape varieties planted in Bordeaux vineyard and consequently, the quality of wine. In some varietals, the attenuation of their fresh fruity character is accompanied by the accentuation of dried-fruit notes [1]. As a new adaptive strategy on climate change, some winegrowers have initiated changes in the Bordeaux blend of vine varieties [2]. This study intends to explore the fruitiness in wines produced from grape varieties adapted to the future climate of Bordeaux. 10 commercial single–varietal wines from 2018 vintage made from the main grape varieties in the Bordeaux region (Cabernet franc, Cabernet-Sauvignon and Merlot) as well as from indigenous grape varieties from the Mediterranean basin, such as Cyprus (Yiannoudin), France (Syrah), Greece (Agiorgitiko and Xinomavro), Portugal (Touriga Nacional) and Spain (Garnacha and Tempranillo), were selected among 19 samples using sensory descriptive analyses. Both sensory and instrumental analyses were coupled, to investigate their fruity aroma expression. For sensory analysis, samples were prepared from wine, using a semi preparative HPLC method which preserves wine aroma and isolates fruity characteristics in 25 specific fractions [3,4]. Fractions of interest with intense fruity aromas were sensorially selected for each wine by a trained panel and mixed with ethanol and microfiltered water to obtain fruity aromatic reconstitutions (FAR) [5]. A free sorting task was applied to categorize FAR according to their similarities or dissimilarities, and different clusters were highlighted. Instrumental analysis of the different FAR and wines demonstrated variations in their molecular composition. Results obtained from sensory and gas chromatography analysis enrich the knowledge of the fruity expression of red wines from “new” grape varieties opening up new perspectives in wine technology, including blending, thus providing new tools for producers.

Extreme canopy management for vineyard adaptation to climate change: is it a good idea?

Climate change constitutes an enormous challenge for humankind and for all human activities, viticulture not being an exception. Long-term strategic changes are probably needed the most, but growers also need to deal with short-term changes: summers that are getting progressively warmer, earlier harvest dates and higher pH in musts and wines. In the last 10-15 years, a relevant corpus of research is being developed worldwide in order to evaluate to which extent extreme canopy management operations, aimed at reducing leaf area and, thus, limiting the source to sink ratio, could be useful to delay ripening. Although extreme canopy management can result in relevant delays in harvest dates, longer term studies, as well as detailed analysis of their implications on carbohydrate reserves, bud fertility and future yield are desirable before these practices can be recommended.

Exploring the regulatory role of the grapevine MIXTA homologue in cuticle formation and abiotic stress resilience

The outer waxy layer of plant aerial structures, known as the cuticle, represents an important trait that can be targeted to increase plant tolerance against abiotic stresses exacerbated by environmental transition. The MIXTA transcription factor, member of the R2R3-MYB family, is known to affect conical shape of petal epidermal cells in Anthirrinum, cuticular thickness in tomato fruit and trichome formation and morphology in several crops. The aim of this study was to investigate the role of the grapevine MIXTA homologue by phenotypic and molecular characterization of overexpressing and knock-out grapevine lines.

Grapes aminoacidic profile: impact of abiotic factors in a climate change scenario

Amino acids play a crucial role in determining grape and wine quality [1]. Recently, research has suggested their metabolism is key to plant abiotic stress tolerance [2]. Therefore, the study of amino acid accumulation in grape berries and its response to environmental factors is of both scientific and economic importance.

Unravelling the microbial community structure and aroma profile of Agiorgitiko wine under different inoculation schemes

Agiorgitiko (Vitis vinifera L. cv.) is the most widely cultivated indigenous red grape variety in Greece, known for the production of Protected Designation of Origin Nemea wines.