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

Related articles…

Sensory profile: a tool to characterize originality of wines produced without sulfites

A trend to reduce chemical inputs in wines exists, especially sulfur dioxide (SO2). This additive is widely used due to its antioxidant, antiseptic and antioxidasic properties. During without sulfites vinification, bioprotection by adding yeast on harvest could be a sulfites alternative. With extension of this wine market, sensory impact linked to sulfites absence and/or sulfites alternative should be evaluated. That’s what this approach proposes to do, focusing on sensory characteristics of wines produced with or without SO2 addition during the winemaking process. METHODS: Wines were elaborated from Merlot grapes of two maturity levels according to three modalities: SO2, without SO2 and bioprotection on harvest (mix of Torulaspora delbrueckii and Metschnikowia pulcherrima). SO2 modality was sulfited throughout the winemaking and aging processes whether other modalities received any addition. After two years of aging, sensory studies were carried out with a specific panel for one month. First, descriptors were generated to differentiate the wines, then panelists were trained on these specific descriptors for five sessions and finally wines sensory profiles were elaborated

ASSESSMENT OF ‘DOLCETTO’ GRAPES AND WINES FROM DIFFERENT AREAS OF OVADA DOCG

Dolcetto (Vitis vinifera L.) is one of the traditionally cultivated varieties in Piedmont (north-east Italy). Dolcetto wines have long been associated with local consumption and they are little known internationally. In particular, the Ovada area (south-east Piedmont), even if it represents a small share of the regional PDO Dolcetto production, is one of the oldest and vocated territory, giving wine also suitable for aging. In this study, the basic composition and phenolic content of Dolcetto grapes for Ovada DOCG wines have been investigated in three different vintages (2020-2022), as well as the main aspects of the derived commercial and experimental wines (basic parameters, phenolics, volatile compounds, sensory properties).

Promoting sustainability in Mediterranean agriculture: insights from the Portuguese vine & wine sector

Agroecology is an integrated approach that simultaneously applies ecological and social concepts and principles to redesign and manage food and agricultural systems, promoting agroecosystems with the necessary biological, socio-economic, and institutional diversity and alignment to support greater efficiency. Thus, several studies have been carried out at promoting the adoption of more agroecological practices among farmers and a wider audience concerning soil conservation and health maintenance.

Effects of wine versus de-alcoholised wine on the microbiota-gut-brain axis in a tau-pathology murine model of Alzheimer’s disease

Alzheimer’s Disease (AD) is the most common disorder associated with cognitive impairment and the main cause of dementia globally. Multiple evidence in the last decade suggest that the gut microbiome plays an important role in the pathogenesis and progression of AD via the microbiota-gut-brain axis, a network wherein microbiome and the central nervous system crosstalk via endocrine, immune, neural, and microbial metabolites signalling pathways.

Evaluation of wood starch content on bench grafting success rate in grapevine

Since the emergence of phylloxera, grafting has been the most used propagation method in viticulture. Despite all the improvement measures implemented in the nurseries, it is frequent that graft success rates vary depending on the nursery process and scion/rootstock combinations. The reasons behind this unsatisfactory behaviour are still unknown and can be diverse, although carbohydrate reserves might be hypothesised to be crucial, since callus, root, and new tissue formation will be built based on them. In order to identify the effect of carbohydrates on grafting success, nine combinations were established based on the starch content in grapevine scionwoods (cv. Tempranillo clone VN69) and rootstocks cuttings (110 Richter clone 237) used for grafting: Low (L), Medium (M), High (H).