terclim by ICS banner
IVES 9 IVES Conference Series 9 THE EFFECT OF COPPER ON THE PRODUCTION OF VARIETAL THIOLS DURING THE ALCOHOLIC FERMENTATION OF COLOMBARD AND GROS MANSENG GRAPE JUICES

THE EFFECT OF COPPER ON THE PRODUCTION OF VARIETAL THIOLS DURING THE ALCOHOLIC FERMENTATION OF COLOMBARD AND GROS MANSENG GRAPE JUICES

Abstract

Nowadays, the rapid growth of vineyards with organic practices and the use of copper as the only fungicide against downy mildew raises again the question of the effect of copper on varietal thiols in wine, especially 3-sulfanylhexan-1-ol (3SH) and its acetate (3SHA). A few decades ago, several works indicated that the use of copper in the vineyard had a negative effect on the content of varietal thiols in Sauvignon blanc wines [1, 2]. However, these studies only considered the concentration of the reduced form (RSH) of varietal thiols, without quantifying the oxidised ones. For this purpose, we proposed to monitor both reduced and oxidised forms of varietal thiols in wine under copper stress during alcoholic fermentation to have a more complete picture of the biological and chemical mechanisms. In the present work, Colombard and Gros Manseng grape juices were fermented under different copper levels (from 0.2 to 3.88 mg/L) to mimic the consequences of organic practices on grape and must. The consumption of thiol precursors and the release of varietal thiols (both free and oxidised forms of 3SH and 3SHA) were monitored by LC-MS/MS according to previously published methods [3, 4]. It was found that the highest copper content (3.6 and 3.88 mg/L for Colombard and Gros Manseng, respectively) significantly increased yeast consumption of precursors (by 9.0 and 7.6% for Colombard and Gros Manseng, respectively). Surprisingly, this higher consumption of precursors was not associated to higher thiol concentrations. Indeed, for both varieties, the content of free thiols in the wine decreased significantly (by 84 and 47% for Colombard and Gros Manseng, respectively) with the increase of copper in the starting must, as already described in the literature [1, 2]. However, the sum “reduced+oxidized” forms of 3SH produced during fermentation was constant for the Colombard must regardless of the copper conditions, which means that the effect of copper was only oxidative for this variety. In Gros Manseng, on the other hand, the sum “reduced+oxidized” forms of 3SH increased with the copper content, up to 90%. This last result suggests that copper probably modifies the regulation of the production pathways of varietal thiols and has also a key role of oxidation. These results complement our knowledge on the effect of copper during thiol-oriented fermentation and the importance of considering both “reduced+oxidized” forms to distinguish chemical from biological effects.

 

1. Darriet, P., et al., Effects of copper fungicide spraying on volatile thiols of the varietal aroma of Sauvignon blanc, Cabernet Sauvignon and Merlot wines. VITIS-GEILWEILERHOF-, 2001. 40(2): p. 93-100.
2. Hatzidimitriou, E., et al., Incidence d’une protection viticole anticryptogamique utilisant une formulation cuprique sur le niveau de maturité des raisins et l’arôme variétal des vins de Sauvignon:(Bilan de trois années d’expérimentation). Journal International des Sciences de la Vigne et du Vin, 1996. 30(3): p. 133-150.
3. Roland, A., et al., Innovative analysis of 3-mercaptohexan-1-ol, 3-mercaptohexylacetate and their corresponding disulfides in wine by Stable Isotope Dilution Assay and nano-liquid chromatography tandem mass spectrometry. Journal of Chromatography A, 2016. 1468: p. 154-163.
4. Bonnaffoux, H., et al., First identification and quantification of S-3-(hexan-1-ol)-γ-glutamyl-cysteine in grape must as a potential thiol precursor, using UPLC-MS/MS analysis and stable isotope dilution assay. Food Chemistry, 2017. 237: p. 877-886

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

G. Dournes1, T. Dufourcq², L. Suc1, J.-R. Mouret1 and A. Roland1*

1. SPO, Université de Montpellier, INRAE, Institut Agro, Montpellier, France
2. Institut Français de la Vigne et du Vin, Pôle Sud-Ouest, Caussens, France

Contact the author*

Keywords

3-sulfanylhexan-1-ol, copper, alcoholic fermentation, yeast

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

INTENSE PULSED LIGHT FOR VINEYARD WASTEWATER: A PROMISING NEW PROCESS OF DEGRADATION FOR PESTICIDES

The use of pesticides for vine growing is responsible for generating an important volume of wastewater. In 2009, 13 processes were authorized for wastewater treatment but they are expensive and the toxicological impact of the secondary metabolites that are formed is not clearly established. Recently photodecomposition processes have been studied and proved an effectiveness to degrade pesticides and to modify their structures (Maheswari et al., 2010, Lassale et al., 2014). In this field, Pulsed Light (PL) seems to be an interesting and efficient process (Baranda et al., 2017). Therefore, the aim of this work was to investigate the PL technology as a new process for the degradation of pesticides.

Read More

USE OF COLD LIQUID STABULATION AS AN OENOLOGICAL TECHNIQUE IN WHITE WINEMAKING: EFFECTS ON PHENOLIC, AROMATIC AND SENSORIAL COMPOSITION

The application of different winemaking techniques helps to modify the basic parameters, phenolic profile, and aroma components influencing the final wine quality. In particular, pre-fermentative processes aim to increase the extraction and preservation of grape native compounds. Among them, cold liquid stabulation (macération sur bourbes) consists in maintaining the grape juice on its lees, in suspended condition at low temperature (0-8 °C) for a variable time (generally from 7 to 21 days). The aim of this work is to apply the cold liquid stabulation on two Italian white grape varieties, Arneis and Cortese, to evaluate the impact on basic parameters, color, polyphenolic compounds (TPI), antioxidant power (DPPH), total polysaccharides, and free and glycosylated volatile compounds (GC-MS analysis) during and after the process.

Read More

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.

Read More

INFLUENCE OF GRAPE RIPENESS ON MACROMOLECULES EXTRACTABILITY FROM GRAPE SKIN TISSUES AND GRAPE SEEDS DURING WINEMAKING

A consequence of climate change is the modification of grape harvest quality and physico-chemical parameters of the obtained wine: increase in alcoholic degree, decrease in pH, and modification of the extractability of macromolecules, which leads to problems of microbiological, tartaric, colour and colloidal stability. In order to respond to these problems, the winemaking processes must be anticipated and adapted with a better knowledge of macromolecule extractability in grapes and their evolution, according to the grape variety, vintage and winemaking process. The purpose of this study was to understand 1) how the harvest date can influence the extractability of macromolecules, polysaccharides and phenolic compounds, which are responsible for wine stability 2) how to adapt the winemaking process to the harvest date in order to optimise wine quality.

Read More

Metabolomics for grape and wine research: exploring the contributions of amino acids to wine flavour

A critical aspect of wine quality is the overall expression of wine flavour, which is formed by the interplay of volatile aroma compounds, their precursors, and taste and matrix components.
Grapes directly contribute to wine only a small number of potent aroma compounds, and the unique
sensory attributes and perceived quality of a wine result from combining 100s of metabolites of grapes, yeast and bacteria, and oak wood.

Read More