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…

Local adaptation tools to ensure the viticultural sustainability in a changing climate

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

Impact of long term agroecological and conventional practices on subsurface soil microbiota in Macabeu and Xarel·lo vineyards

There is a growing trend on the transition from conventional to agroecological management of vineyards. However, the impact of practices, such as reduced-tillage, organic fertilization and cover crops, is not well-understood regarding the soil microbial diversity, and its relationship with the soil physicochemical properties in the subsurface depth near the rooting zone. Soil bacterial diversity is an important contributor towards plant health, productivity and response to environmental stresses. A field experiment was conducted by sampling subsurface soil bacterial community (NGS and qPCR) near to the root zone of Macabeu and Xarel·lo vineyards, located at the Penedes. 3 organic (ECO) and 3 conventional (CON) vineyards, with more than 10 years of respective management were sampled (n=5 each plot). ECO practices did not affect bacterial and fungal abundance but increased significantly the ammonium oxidizing bacteria and alpha-diversity (Inv.Simpson). Interestingly beta-diversity was significantly affected by the management strategy. ANOSIM-tests revealed a significative effect of the management (ecological vs conventional) and plot, on the soil microbial structure (ASV abundance). Main phyla depicted were Proteobacteria, Actinobacteria and Acidobacteria, whose relative abundances were not affected by the management. EdgeR assay revealed a significant increase of Cyanobacteria and decrease of Gemmatimonadetes and Firmicutes phyla in ECO. Interestingly, the grapevine variety was not correlated with the soil microbial community structure. Mantel-test revealed an important correlation (Spearman) of some physicochemical parameters with the soil microbiota structure, in order of importance: texture, EC, pH Ca/Mg, Mg/P, K+, Mg2+, Ca2+, SO42-, and OM. N-NH4 and NTK, which were higher in the ECO managed soils, did not correlated significantly with the soil microbiome population. The results revealed the importance of combining a deep physicochemical characterization of each replicate with the microbial diversity assessment to gain better insights on the relationship between soil microbiome and vineyard management.

Modeling island and coastal vineyards potential in the context of climate change

Climate change impacts regional and local climates, which in turn affects the world’s wine regions. In the short term, these modifications rises issues about maintaining quality and style of wine, and in a longer term about the suitability of grape varieties and the sustainability of traditional wine regions. Thus, adaptation to climate change represents a major challenge for viticulture. In this context, island and coastal vineyards could become coveted areas due to their specific climatic conditions. In regions subject to warming, the proximity of the sea can moderate extremes temperatures, which could be an advantage for wine. However, coastal and island areas are particular prized spaces and subject to multiple pressures that make the establishment or extension of viticulture complex.
In this perspective, it seems relevant to assess the potentialities of coastal and island areas for viticulture. This contribution will present a spatial optimization model that tends to characterize most suitable agroclimatic patterns in historical or emerging vineyards according to different scenarios. Thanks to an in-depth bibliography a global inventory of coastal and insular vineyards on a worldwide scale has been realized. Relevant criteria have been identified to describe the specificities of these vineyards. They are used as input data in the optimization process, which will optimize some objectives and spatial aspects. According to a predefined scenario, the objectives are set in three main categories associated with climatic characteristics, vineyards characteristics and management strategies. At the end of this optimization process, a series of maps presents the different spatial configurations that maximize the scenario objectives.

Legacy of land-cover changes on soil erosion and microbiology in Burgundian vineyards

Soils in vineyards are recognized as complex agrosystems whose characteristics reflect complex interactions between natural factors (lithology, climate, slope, biodiversity) and human activities. To date, most of the unknown lies in an incomplete understanding of soil ecosystems, and specifically in the microbial biodiversity even though soil microbiota is involved in many key functions, such as nutrient cycling and carbon sequestration. Soil biological properties are indicative of soil quality. Therefore, understanding how soil communities are related to soil ecosystem functioning is becoming an essential issue for soil strategy conservation. Here, we propose to assess the importance of land-cover history on the present-day microbiological and physico-chemical properties. The studied area was selected in the Burgundian vineyards (Pernand-Vergelesses, Burgundy, France) where land occupation has been reconstructed over the last 40 years. Soil samples were collected in five areas reflecting various land cover history (forest, vineyards, shifting from forest to vineyards). For each area, physico-chemical parameters (pH, C, N, P, grain size) were measured and DNA was extracted to characterize the abundance and diversity of microbial communities. The obtained results show significant differences in the five areas suggesting that present-day microbial molecular biomass and bacterial taxonomic is partly inherited from past land occupation. Over longer period of time, such study of land-uses legacies may help to better assess ecosystem recovery and the impact of management practices for a better soil quality and vineyards sustainability.

Long-term drought resilience of traditional red grapevine varieties from a semi-arid region

In recent decades, the scarcity of water resources in agriculture in certain areas has been aggravated by climate change, which has caused an increase in temperatures, changes in rainfall patterns, as well as an increase in the frequency of extreme phenomena such as droughts and heat waves. Although the vine is considered a drought-tolerant specie, it has to satisfy important water requirements to complete its cycle, which coincides with the hottest and driest months. Achieving sustainable viticulture in this scenario requires high levels of efficiency in the use of water, a scarce resource whose use is expected to be severely restricted in the near future. In this regard, the use of drought-tolerant varieties that are able to maintain grape yield and quality could be an effective strategy to face this change. During three consecutive seasons (2018-2020) the behavior in rainfed regime of 13 traditional red grapevine varieties of the Spain central region was studied. These varieties were cultivated in a collection at Centro de Investigación de la Vid y el Vino de Castilla-La Mancha (IVICAM-IRIAF) located in Tomelloso (Castilla-La Mancha, Spain). Yield components (yield, mean bunch and berry weight, pruning weight), physicochemical parameters of the musts (brix degree, total acidity, pH) and some physiological parameters related with water stress during ripening period (δ13C, δ18O) were analysed. The application of different statistical techniques to the results showed the existence of significant differences between varieties in their response to stressful conditions. A few varieties highlighted for their high ability to adapt to drought, being able to maintain high yields due to their efficiency in the use of water. In addition, it was possible quantify to what extent climate can be a determinant in the δ18O of musts under severe water stress conditions.