Terroir 2020 banner
IVES 9 IVES Conference Series 9 Characterization of the thiol aromatic potential of a new resistant grape variety: Floreal

Characterization of the thiol aromatic potential of a new resistant grape variety: Floreal

Abstract

Aims: Due to climate change and the desire to decrease enological inputs (organic farming), the vineyard has to be modified and the selection of new resistant grape varieties as an alternative is researched intensively today. From January 2018, four new grape varieties that are resistant against mildew and odium have been added to the official catalogue and are now available for planting new vineyards in France: Floreal, Artaban, Vidoc and Voltis. Floreal wines have been described as “very aromatic and very intense with specific notes of grapefruit” during tasting. Unfortunately, there is no data, either qualitative or quantitative, in literature to describe the aromatic quality of this resistant grape variety.

Today we know that the olfactory descriptor of grapefruit is mainly characteristic of 3-mercaptohexan-1-ol (3MH). To reach a deeper understanding of the aromatic potential of Floreal grapes, a combined study of the effects of both viticultural (nitrogen foliar spraying) and enological (cold lees settling) parameters has been carried out.

Methods and Results: After pressing Floreal grapes, corresponding must (with or without cold settling) was inoculated with a high b-lyase activity dry yeast strain at 20 g/hL. Temperature of fermentation was maintained close to 16 °C and we monitored the kinetic of alcoholic fermentation by measuring the rate of CO2 release. Following this, several parameters were quantified: cysteinylated and glutathionylated thiol precursors (during grape maturation and in the must), and 3MH (in the final wine) by SIDA-UPLC-MS/MS. An innovative analysis of both reduced and oxidized forms of 3MH and 3MHA has been also performed in order to indicate possible “wine oxidizability” of such a resistant variety. 

Conclusion: 

First of all, Floreal wines have concentrations in 3MH and 3MHA close to 1300 ng/L (sum of both compounds) which is relatively low in comparison with Colombard or Sauvignon blanc from Gers or Loire Valley, respectively. Thus, Floreal wine aromaticity cannot be only explained by 3MH and 3MHA, and other powerful thiols may be implicated such as 4MMP, opening an avenue for identification of new aroma compounds. 

A surprising and interesting result was the fact that cold lees settling did not significantly improve the level of both 3MH and 3MHA in Floreal wines, whereas this technological practice is commonly used for its positive effect in non-resistant varieties such as Sauvignon blanc. 

Significance and Impact of the Study: Therefore, accurate characterization of this new grape variety and those that will be developed in the coming years represents a great challenge: adapting viticultural and enological practices to produce high quality wines in the future. 

DOI:

Publication date: March 25, 2021

Issue: Terroir 2020

Type : Video

Authors

Gabriel Dournes1, Erick Casalta1, Alain Samson2, Evelyne Aguera2, Jean-Roch Mouret1, Aurélie Roland1*

1UMR SPO, INRAE, Univ Montpellier, Montpellier SupAgro, 2 place Pierre Viala, 34060 Montpellier Cedex 2, France
2 UE Pech Rouge, INRAE, 11430 Gruissan, France

Contact the author

Keywords

Thiol precursors, 3-mercaptohexan-1-ol, nitrogen foliar spraying, cold settling 

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

Sustaining wine identity through intra-varietal diversification

With contemporary climate change, cultivated Vitis vinifera L. is at risk as climate is a critical component in defining ecologically fitted plant materiel. While winegrowers can draw on the rich diversity among grapevine varieties to limit expected impacts (Morales-Castilla et al., 2020), replacing a signature variety that has created a sense of local distinctiveness may lead to several challenges. In order to sustain wine identity in uncertain climate outcomes, the study of intra-varietal diversity is important to reflect the adaptive and evolutionary potential of current cultivated varieties. The aim of this ongoing study is to understand to what extent can intra-varietal diversity be a climate change adaptation solution. With a focus on early (Sauvignon blanc, Riesling, Grolleau, Pinot noir) to moderate late (Chenin, Petit Verdot, Cabernet franc) ripening varieties, data was collected for flowering and veraison for the various studied accessions (from conservatory plots) and clones. For these phenological growing stages, heat requirements were established using nearby weather stations (adapted from the GFV model, Parker et al., 2013) and model performances were verified. Climate change projections were then integrated to predict the future behaviour of the intra-varietal diversity. Study findings highlight the strong phenotypic diversity of studied varieties and the importance of diversification to enhance climate change resilience. While model performances may require improvements, this study is the first step towards quantifying heat requirements of different clones and how they can provide adaptation solutions for winegrowers to sustain local wine identity in a global changing climate. As genetic diversity is an ongoing process through point mutations and epigenetic adaptations, perspective work is to explore clonal data from a wide variety of geographic locations.

Influence of climatic conditions on grape composition of Tempranillo in La Mancha DO (Spain)

The aim of this work was to analyze the variability in grape composition of the Tempranillo cultivar related to climatic conditions, in La Mancha Designation of Origin. Grape composition (sugar content, total acidity, pH, malic acid, and total and extractable anthocyanins) recorded during ripening, were analysed for the period 2000-2019. The weather conditions at daily time scale, recorded during the same period, were also evaluated. The relationships between grape parameters with climatic variables related to temperature and to water deficits, referring different periods between phenological events along the growing cycle, were evaluated using regression analysis. High variability in grape composition was observed in the period analysed. Total acidity varied between 3.7 and 7.3 gL-1 while malic acid varied between 1.2 and 4 gL-1. The extractable anthocyanins ranged between 526 and 972 mgL-1, and total anthocyanins ranged between 922 and 1388 mgL-1, being the lowest values recorded in the hottest year (2017). Total acidity decreased 0.77 gL-1 for an increase of 100 GDD, while malic acid decrease in 0.42 gL-1 for the same GDD increase, being the period between veraison and harvest the one that seemed to have higher influence on acidity. In addition, it was confirmed that increasing water deficits decreased acidity. Total and extractable anthocyanins increased in about 210 and 105 mgL-1, respectively, with an increase of 100 GDD from veraison to harvest, and the increase in water deficits favour the increase of anthocyanins, both total and extractable anthocyanins. Total and extractable anthocyanins concentration increased in 35 and 22 mgL-1 per an increase of 10 mm in the water deficit. These results can be of interest to understand the potential changes that grapes composition may suffer under future warmer climates.

Simulating climate change impact on viticultural systems in historical and emergent vineyards

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Climate, Viticulture, and Wine … my how things have changed!

The planet is warmer than at any time in our recorded past and increasing greenhouse emissions and persistence in the climate system means that continued warming is highly likely. Climate change has already altered the basic framework of growing grapes for wine production worldwide and will likely continue to do so for years to come. The wine sector can continue to play an important role in leading the agricultural sector in addressing climate change. From developing on…