Macrowine 2021
IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 First characterization of thiol precursors in colombard and gros manseng: comparison of two cultivation practices

First characterization of thiol precursors in colombard and gros manseng: comparison of two cultivation practices

Abstract

AIM: Organic production of wine in the past years has known an important augmentation. This type of cultivation practice switches synthetic phytosanitary product for copper-based protection as fungicide. While the effect of copper on soil and vine is understood, few data are published concerning its impact on wine aromas (Darriet et al. 2001) and even less concerning varietal thiol. The aim of this work was to characterize the thiol aromatic potential of Colombard and Gros Manseng grapes and to investigate the effect of copper on thiol precursor biogenesis. We selected 30 parcels (15 conventional and 15 organic) with sampling at harvest for 18 of them and 3 sampling dates during ripening for the other 12 parcels. Chemical analyses of thiol precursors were performed by adapting an UPLC-MS/MS method based upon Stable Isotope Dilution Assay (Bonnaffoux et al. 2017)

RESULTS: With this first characterization, we demonstrated that both varieties presented concentrations of glutathionylated (G3SH) and cysteinylated (Cys3SH) precursors of 3-sulfanylhexan-1-ol up to 454 µg/kg and 21 µg/kg respectively. No precursors of the 4-sulfanyl-4-methylpentan-2-one were detected. So, Colombard and Gros Manseng were ranked in the top of varietal thiol producers with Sauvignon and Pinot Gris grapes (Pena-Gallego et al. 2012). By comparing the copper protected parcels to the others, we identified a significant decrease (p-value = 0.01) of G3SH content in organic Gros Manseng grapes which was around 30%. This could represent a loss in 3SH of 1000 ng/kg in finished wines if a conversion rate of 3% between G3SH and 3SH was considered. On the opposite, Colombard grapes remained unaffected by the copper spraying with no effect on the precursors content at harvest. We also analyzed the accumulation kinetics of thiol precursors under the two protection methods (copper or not). No accumulation of thiol precursors between seven days prior and after the harvest was observed in Colombard grapes which was inconsistent with literature on other grape varieties such as Sauvignon B. or Melon B. (Roland et al. 2010). Gros Manseng grapes showed significant accumulation for conventional culture (161 µg/kg to 356 µg/kg) over the two last weeks of ripening. Furthermore, copper treated parcels of Gros Manseng have no accumulation through the two-week study. However, Pearson test did not show a direct correlation between copper content and G3SH suggesting a possible interaction of copper with thiol precursors making them not analyzable under our conditions or a modification of vine metabolism.

CONCLUSION:

We characterized for the first time two grapes varieties (Colombard and Gros Manseng) that have high potential towards varietal thiols such as Sauvignon. We identified a negative copper effect on Gros Manseng variety for both precursors content at harvest and accumulation kinetics while Colombard remained unaffected.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Gabriel Dournes, Arnaud VERBAERE, Frédéric LOPEZ, Thierry DUFOURCQ, Jean-Roch MOURET, Aurélie ROLAND

SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France, IFV Sud-Ouest, Château de Mons, 32100 Caussens, France

Contact the author

Keywords

copper, thiol precursors, colombard, gros manseng, wine

Citation

Related articles…

Solid Rectified Concentrated grape Must (SRCM) in sparkling wines production: studying the sensory impact of an innovative sugar substrate

The production of sparkling wines requires sugars for the second fermentation. The Solid Rectified Concentrated Must (SRCM) is a water free crystalline form of grape sugar, offering a purer, more stable, and easier-to-use alternative to the liquid Rectified Concentrated Must (RCM).

Technical innovation and quality control of wine production in China

Recent decades have witnessed an evolving trend of diverse product types, improved quality, and green, low-carbon, and sustainable development in chinese wine market. A quality evaluation system, namely, with a dual orientation of “flavor compounds” and “sensory evaluation” is used as guidance for winemaking innovation in China.

Influence of Lactiplantibacillus plantarum and Oenococcus oeni strains on sensory profile of sicilian nero d’avola wine after malolactic fermentation.

AIM: Malolactic fermentation is a process of decarboxylation of L-malic acid into L-lactic acid and carbon dioxide that leads to deacidification, modification of odors and flavors of wines [1]

Saccharomyces cerevisiae intraspecies differentiation by metabolomic signature and sensory patterns in wine

AIM: The composition and quality of wine are directly linked to microorganisms involved in the alcoholic fermentation. Several studies have been conducted on the impact of Saccharomyces cerevisiae on volatile compounds composition after fermentation. However, if different studies have dealt with combined sensory and volatiles analyses, few works have compared so far the impact of distinct yeast strains on the global metabolome of the wine.

Impact of chitosan treatment on the physico-chemical features of a sangiovese red wine

Chitosan is gaining interest in red winemaking thanks to its ability to inhibit the development of Brettanomyces spp. yeast, or other undesired wine microbial threats. However, little is known about potential side-effects of its addition on the physico-chemical parameters of red wines.