 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Chemical diversity of 'special' wine styles: fortified wines, passito style, botrytized and ice wines, orange wines, sparkling wines 9 Influence of withering on valpolicella docgs grapes volatile composition

Influence of withering on valpolicella docgs grapes volatile composition

Abstract

AIM: The blend of grapes used in the production of the four Valpolicella PDOs red wines, namely Valpolicella, Valpolicella Classico Superiore, Recioto della Valpolicella and Amarone della Valpolicella is quite unique, and includes two main varieties Corvina and Corvinone, and other minor varieties. To a very large extent all these grapes are only grown in the province of Verona. One of the main characteristics of Valpolicella is the use of grapes that are submitted to post-harvest withering. The aim of this study was therefore to evaluate the evolution of the free and glycosidically-bound volatile compounds in Corvina and Corvinone grapes under real production conditions.

METHODS: Corvina and Corvinone grapes from five different vineyards, at harvest and after 90 days of withering, were obtained from local winery during three consecutive vintages. Grape extracts were prepared with 800 grams of hand-crushed destemmed berries to which 141 mL of ethanol, 400 µg of dimethyl dicarbonate and 80 mg of potassium metabisulphite were added. Bottles were closed with screw caps and kept at 22 ± 1 °C for 14 days, during which they were hand stirred two times per day without opening the caps. Free volatile compounds and glycosidic precursors have been analysed by means of SPE- and SPME-GC-MS methods.

RESULTS: Most free and bound volatile increased in concentration with withering, in agreement with the fact that this process involve a significant degree of water loss (typically around 30%). However, for some compounds a decrease was observed with withering, including free cis-3-hexen-1-ol, 3-hydroxy-β-damascone and methyl salicylate. In the case of terpenes, more complex withering varieties interactions were observed. While in Corvinone all free terpenes increased with withering, in Corvina different patterns were observed, since β-citronellol and other terpenes increased while geraniol, linalool and α-terpineol showed similar content after treatment. Likewise, bound terpenes decreased in Corvina with withering, while in Corvinone they increased in two vintages out of three.

CONCLUSIONS:

Withering is a complex process in which, in addition to the simple water loss, a number of complex biochemical transformations occur inside the grape berry. These can affect volatile compounds of potential sensory relevance for Valpolicella wines in particular terpenes and norisoprenoids. Some variety-related differences in the evolution of certain aroma compounds during withering have been observed, with important consequences for the practical management of post-harvest withering.

ACKNOWLEDGMENTS:

Azienda Agricola f.lli Tedeschi is acknowledged for financial support

DOI:

Publication date: September 15, 2021

Issue: Macrowine 2021

Type: Article

Authors

Giovanni Luzzini

University of Verona,Davide SLAGHENAUFI, University of Verona Maurizio, UGLIANO, University of Verona Riccardo TEDESCHI, Azienda Agricola F.lli Tedeschi

Contact the author

Keywords

withered grapes, grape volatile compounds, valpolicella, amarone, recioto

Citation

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.

Correspondence between physiological plant variables and carbon isotope composition in different climate winegrape regions

The climate is the environmental factor that contributes with greater weight in the variability of the yield and the composition of the grape, therefore, it is key in the determination of the typicity of the product. Of the environmental factors, the evolution of water availability conditions, among other things, the biochemical evolution of the compounds of the grape and the type of wine to be elaborated. An integrating parameter of the hydric state of the plant is the carbon isotopic composition (δ13C). This indicator is a useful parameter to characterize the water status during the maturation period and estimate the transpiration efficiency or water use efficiency (EUA) in the vine.

In vitro regeneration of grapevine cv. Aglianico via somatic embryogenesis: preliminary studies for next genome editing applications

Italy is a rich hub of viticultural biodiversity harboring hundreds of indigenous grape varieties that have adapted over centuries to the diverse climatic and geographic conditions of its regions. Preserving this biodiversity is essential for maintaining a diversified genetic pool, crucial for addressing future challenges such as climate change and emerging plant diseases. Rising temperatures, precipitation pattern variations, and extreme weather events can affect grape ripening, crop quality, and contribute to disease development. Integrated disease management necessitates exploration of novel strategies. Biotechnologies emerge as a significant player in tackling modern viticulture challenges.

Effect of the addition of peptidic hydrolysates from grape pomace by-products to red wines in warm regions

High temperatures typical of warm climates cause the colour of red wines to become increasingly unstable over time.

Long-term vineyard sustainability index

The impact of viticulture on soil can be determined by comparing the biophysical properties that represent soil health at a particular site and depth with those same properties in soil considered to represent the ‘pre-vineyard’ state (the headland). Information gathered by this method shows the changes in soil properties following the change to viticulture depend on individual vineyard management and environment.