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…

EVALUATION OF A SEAWEED EXTRACT OF RUGULOPTERYX OKAMURAE AGAINST ERYSIPHE NECATOR IN GRAPEVINE

Powdery mildew, caused by Erysiphe necator, is a widespread disease that causes high economical losses in viticulture. The main strategy to control the disease is the recurrent application of sulphur based phytochemical compounds. However, in order to reduce their accumulation in the environment and promote the sustainability of the sector, the European Commission has applied restrictions to the number of pesticide treatments and the maximum quantity of fungicides to be applied in viticulture. Seaweeds, in particular macroalgae, are marine resources rich in sulphated polysaccharides with bio-protective potential for the plant, representing an environmentally-friendly alternative approach for sustainable wine production.

Read More

NEW METHOD FOR THE QUANTIFICATION OF CONDENSED TANNINS AND OTHER WINE PHENOLIC COMPOUNDS USING THE AUTOMATED BIOSYSTEMS SPICA ANALIZER

Wine phenolic compounds are important secondary metabolites in enology due to their antioxidant and nutraceutical properties, and their role in the development of color, taste, and protection of wine from oxidation and spoilage. Tannins are valuable phenolic compounds that contribute significantly to these wine properties, especially in mouthfeel characteristics; however, tannin determination remains a significant challenge, with manual and time-consuming methods or complex methodologies. The purpose of this study is to propose a novel method for quantifying condensed tannins in finished wine products.

Read More

INFLUENCES OF SO2 ADDITION AND STORAGE CONDITIONS IN THE DETERMINATION OF MEAN DEGREE OF POLYMERIZATION OF PROANTHOCYANIDINS IN AGED RED WINES

The structural diversity is one of the most remarkable characteristics of proanthocyanidins (PA). Indeed, PA in wines may vary in the B-ring and C-ring substitutes, the C-ring stereochemistry, the degree of polymerization (DP) and the linkage between the monomers. Knowing in detail the structural characteristics of the PA of a wine can help us to understand and modulate several sensorial characteristics of the wine, such as color, antioxidant properties, flavor, and mouthfeel properties. In the last years was discovered and confirmed the presence of sulfonated monomeric and oligomeric flavan-3-ols in wine [1], as well as was pointed out their importance in wine quality [1,2].

Read More

PHOTO OXIDATION OF LUGANA WINES: INFLUENCE OF YEASTS AND RESIDUAL NITROGEN ON VSCS PROFILE

Lugana wines are made from Turbiana grapes. In recent times, many white and rosé wines are bottled and stored in flint glass bottles because of commercial appeal. However, this practice could worsen the aroma profile of the wine, especially as regards the development of volatile sulfur compounds (VSCs). This study aims to investigate the consequences of exposure to light in flint bottles on VSCs profile of Lugana wines fermented with two different yeasts and with different post-fermentation residual nitrogen.

Read More

NEW INSIGHTS INTO THE EFFECT OF TORULASPORA DELBRUECKII/SACCHAROMYCES CEREVISIAE INOCULATION STRATEGY ON MALOLACTIC FERMENTATION PERFORMANCE

Winemaking is influenced by micro-organisms, which are largely responsible for the quality of the product. In this context, Non-Saccharomyces and Saccharomyces species are of great importance not only because it influences the development of alcoholic fermentation (AF) but also on the achievement of malolactic fermentation (MLF). Among these yeasts, Torulaspora delbrueckii allows in sequential inoculation with strains of S. cerevisiae shorter MLF realizations [5] . Little information is available on the temporal effect of the presence of T. delbrueckii on (i) the evolution of AF and (ii) the MLF performance.

Read More