 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

Analytical characterization of Oloroso Sherry in Sherry Cask seasoning and its influence in the ageing of brandy de jerez

Oloroso Sherry is a typical fortified wine from Jerez de la Frontera (south of Spain). It is one of the most used in the seasoning of oak barrels, called Sherry Cask, destined in this area for ageing brandies or condiments as wine vinegars. Brandy de Jerez is an European Geographical Indication for grape-derived spirits. Its special organoleptic characteristics are due to its traditional dynamic ageing in Sherry Casks. American oak is the most common wood employed in Jerez area, where Brandy de Jerez is exclusively manufactured. During ageing period of Sherry and brandies, the wood is not only a container, it is involved in several physicochemical process with the Sherry or the distillate. Oak wood is the responsible of the presence of many compounds in the products, affecting their aroma and chemical composition and having a high influence in their final quality. Moreover, the seasoned wood with Sherry wine could transfer the compounds from wine into the brandy, improving its aroma and flavor.

Comparison of plant nutrients in the soil solution and bleeding sap of grapevine cvs

In this study macro and micro nutrients of plants (N = NH4 + NO3 , P, K, Ca, Na, Zn, Mn, Fe and Cu) were determined both in soil solution and bleeding sap and compared each other. Bleeding sap was collected from the nine varieties of grapevine Cvs. grafted on 5BB rootstock and grown in different soil conditions. For all varieties, plant nutrients content in bleeding sap as higher than in soil solution except for Ca and Na. While in soil solution Ca content was found at 10209 ppm, this value in bleeding sap was 49.20 ppm (Kozak Beyazy), 55.38 ppm (Trakya Ylkeren), 50.37 (Cardinal) and 74.27 ppm (Tekirdaô Çekirdeksizi) respectively. For the same varieties the Na values were as follows : 7.16 ppm (in soil solution) : 4.8, 3.23, 4.21,4.58 ppm (in bleeding sap) respectively. K content in bleeding sap was higher than in soil solution for a few varieties, and lower in some varieties. Traces of Fe and Cu were found in both media.

Cultures des vignobles en forte pente: possibilités de mécanisation. Effet de l’exposition et de l’orientation des rangs

Plus de la moitié du vignoble suisse (14’000 ha) est situé sur des coteaux en forte pente (> 30%). Dans certains vignobles, la pente naturelle du terrain a été réduite par la construction de terrasses soutenues par des murs.

“Terroir” and climate change in Franconia / Germany

Franconia which is a “cool climate” winegrowing region is well known for its fruity white wines. The most common grape cultivars are Silvaner and Mueller-Thurgau.

LARGE SURVEY OF THE CHEMICAL COMPOSITION OF WINES RESULTING OF THE PRESSING OF RED WINE MARC. FIRST RESULTS

In the Bordeaux vineyards, press red wine represents about 15% of the volume of wines. Valuing this large volume of press wine is necessary from an economic point of view, of course, but also because of their organoleptic contribution to the blend. Nevertheless, there is a lack of recent knowledge on the composition of press wines. This work aims to establish an initial assessment of their composition (aromatic and polyphenolic) and to set up hypothesis on to the links with their sensorial identity.