IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Profiling the Metschnikowia yeast populations in spontaneous fermentation of Amarone della Valpolicella

Profiling the Metschnikowia yeast populations in spontaneous fermentation of Amarone della Valpolicella

Abstract

The microbial diversity during spontaneous grape must fermentation has a determinant influence on the chemical composition and sensory properties of wine. Therefore, yeast diversity is an important target to better understand wine regionality. Hence, the aim of this study was to isolate, identify, and characterize the yeast core microbiota in grape must during the early stage of lab-scale spontaneous fermentation of withered grapes to produce Amarone della Valpolicella wine (Verona, Italy). At the end of the withering process, chosen grape bunches, mainly of Corvina and Corvinone varieties, were pressed and transferred to glass bottles in the laboratory for spontaneous fermentation (SF). To investigate the impact of grape washing on microbial removal, one batch of grapes was submitted to a washing step in aqueous solution (1% w/v citric acid) at the winery before pressing. Microbial composition was investigated during the first five days of fermentation, a stage known for greater variability of microorganisms, isolating yeast colonies from WL agar plates. Overall, 67 colonies were purified and the partial 26S rRNA gene sequencing allowed the identification of six different species, among which Metschnikowia spp. was prevalent. Indeed, 42 isolates of this genus were obtained, deriving from musts of washed grapes (22) and from non-washed grapes (20). Interestingly, the washing step did not impact on the presence of pulcherrimin-producing isolates. A more in-depth characterization was carried out on those 42 isolates, as Metschnikowia spp. are acknowledged to contribute to the diversity and complexity of wine taste. A strain level analysis was performed by means of fingerprinting profiles (primer (GTG)5) and phenotypic characterization (sulfite reductase, β-glucosidase, and esterase enzymatic activities). 11 genotypic profiles and 6 different phenotypic combinations were observed among the 42 isolates. Considering both approaches, it was possible to define the presence of 19 strains of Metschnikowia spp., most of them isolated only once, but some present in both washed and non-washed grapes, throughout the whole sampling period. Results obtained in this study shed light on the native Metschnikowia yeast community of washed and non-washed withered grapes, that is composed by diverse strains, and highlight that this biodiversity can be underestimated if only genotypic or phenotypic properties are investigated. This diversity represents a reservoir of strains with enological/pro technological significance that could be applied and combined to improve the sensory characteristics of wine and fermented beverages. 

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Martelli Francesco1, Checchia Ilaria1, Troiano Eleonora1, Gatto Veronica1, Leal Binati Renato1, Torriani Sandra1 and Felis Giovanna E.1

1Department of Biotechnology, University of Verona, Italy

Contact the author

Keywords

non-Saccharomyces; microbial diversity; spontaneous fermentation; wine quality; grape washing

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Using unmanned aerial vehicle with multispectral camara to efficiently and precisely monitor the incidence of downy mildew and technical maturity of beibinghong (vitis amurensis Rpru.) grapes 

Multispectral unmanned aerial vehicle (UAV) has been successfully applied in monitoring vine vegetative growth, however, there are still potential relationships between remote sensing vegetation indexes (vis) and vine condition or grape quality, so it is worthy a deeper investigation to make a better use of UAV. One of the purposes of the study is to find out vis that could denote the severity of downy mildew (DM), so that precise and differentiated control strategies would be adopted subsequently.

Budburst delay and berry ripening after vegetal oil application in Austria

Occurrence of freezing temperatures in early spring when grapevine shoots are developing is termed late frost in viticulture. Young green tissues are very sensible to temperatures below zero and damages often lead to important yield and quality losses such as the case in Europe in 2017. An indirect method to avoid late frost damage in vineyards consist in delaying the budburst. Previous research reported similar effects by applying vegetal oil on dormant buds. Here, we tested the application of rapeseed vegetal oil during late winter to delay the budburst on two V.vinifera cultivars of interest in Austria, Grüner Veltliner (GV) and Zweigelt (ZW).

Climate projections over France wine-growing region and its potential impact on phenology

Climate change represents a major challenge for the French wine industry. Climatic conditions in French vineyards have already changed and will continue to evolve. One of the notable effects on grapevine is the advancing growing season. The aim of this study is to characterise the evolution of agroclimatic indicators (Huglin index, number of hot days, mean temperature, cumulative rainfall and number of rainy days during the growing season) at French wine-growing regions scale between 1980 and 2019 using gridded data (8 km resolution, SAFRAN) and for the middle of the 21th century (2046-2065) with 21 GCMs statistically debiased and downscaled at 8 km. A set of three phenological models were used to simulate the budburst (BRIN, Smoothed-Utah), flowering, veraison and theoretical maturity (GFV and GSR) stages for two grape varieties (Chardonnay and Cabernet-Sauvignon) over the whole period studied. All the French wine-growing regions show an increase in both temperatures during the growing season and Huglin index. This increase is accompanied by an advance in the simulated flowering (+3 to +9 days), veraison (+6 to +13 days) and theoretical maturity (+6 to +16 days) stages, which are more noticeable in the north-eastern part of France. The climate projections unanimously show, for all the GCMs considered, a clear increase in the Huglin index (+662 to 771 °C.days compared to the 1980-1999 period) and in the number of hot days (+5.6 to 22.6 days) in all the wine regions studied. Regarding rainfall, the expected evolution remains very uncertain due to the heterogeneity of the climates simulated by the 21 models. Only 4 regions out of 21 have a significant decrease in the number of rainy days during the growing season. The two budburst models show a strong divergence in the evolution of this stage with an average difference of 18 days between the two models on all grapevine regions. The theoretical maturity is the most impacted stage with a potential advance between 40 and 23 days according to wine-growing regions.

Zonazione e vitigni autoctoni nel sud della Basilicata: metodologie integrate per la caratterizzazione di ambienti di elezione di biotipi storici finalizzati a vini di territorio nella DOC “Terre dell’Alta Val d’Agri”

I territori della DOC “Terre dell’Alta Val d’Agri”, a Sud della regione Basilicata, si caratterizzano per una elevata biodiversità autoctona autoselezionatesi su ambienti ecologicamente ben definiti,

Effects of post-veraison irrigation dose on Cabernet-Sauvignon vines in a dry and warm season in Valencia, Spain

In the old-world viticulture, there is a common but most often not scientifically proved consideration that supplemental irrigation should detrimentally affect berry and wine composition. In the semi-arid