What metabolomics teaches us about wine shelf life

Three compounds, 3-mercaptohexanol (3MH), 3-mercaptohexyl-acetate (3MHA) and 4-mercapto-4-methylpentan-2-one (4MMP), also known as varietal thiols, have been identified to contribute positively to wine aroma and are responsible for the distinct gooseberry, grapefruit, guava and box tree character found in Sauvignon blanc wines. Certain volatile thiol compounds though, can cause off-aromas of onion, garlic, rubber and rotten egg, this group of molecules is known as reductive sulphur compounds (RSC). This study looks into how the addition of sulphur-compounds to Sauvignon blanc juice contributes to the varietal thiol (3MH and 3MHA) concentration and reductive sulphur compound concentration in South African Sauvignon blanc wine.

Management of plant-parasitic nematodes is typically focused on preplant fumigation, especially in a vineyard replant scenario. While the data are clear that this practice reduces nematodes immediately after application, which is useful in annually-cropped systems, does it have staying power in perennial cropping systems? The northern root-knot nematode Meloidogyne hapla reduces the overall lifespan and productivity of vineyards, but it does so over a long time period (slow, chronic decline). In two different commercial own-rooted V. vinifera vineyards, both undergoing vineyard replanting, we explored whether preplant fumigation reduced M. hapla densities in soils immediately after application. At one of these locations, we have explored the long-term effect of fumigation by monitoring the site for seven years post fumigation.

The typicality of a wine, as well as its aromatic identity, are attributes that are highly sought after and requested by the current market. It is therefore of considerable technological interest to investigate the aromatic aspects of specific wines and to identify the odorous substances involved.In this thesis work, the characterization of the aromatic composition of Prosecco wines available on the market with a price range between 7 and 13 euros was carried out. These wines came from three different areas of origin such as Valdobbiadene, Asolo and Treviso.

Aim: Sauvignon blanc displays a range of styles that can include prominent tropical and passionfruit aromas. Both sensory evaluation and chemical analysis have confirmed the above-average presence of ‘varietal thiols’ in the Sauvignon blanc wines from Marlborough, New Zealand.

Pour son travail de cartographie et de caractérisation des terroirs, la Cellule Terroirs Viticoles utilise la méthode développée par l’Unité Vigne et Vin du Centre INRA d’Angers. Cette méthode reconnue au niveau international est appliquée dans les vignobles du Val de Loire à l’échelle du 1/10 000e et est valorisée par des éditions d’Atlas Viticoles à destination des viticulteurs et des organismes techniques.