REVINE project : regenerative agricultural approaches to improve ecosystem services in Mediterranean vineyards

AIM: The aim of this work was to study the inhibitory effect of the three most frequently used wine antioxidants – sulfur dioxide, ascorbic acid and glutathione – on the kinetics of browning caused by Botrytis cinerea laccase using a grape juice synthetic model in which (-)-epicatechin was the substrate.

In the production of sparkling wines, during the second fermentation, mannoproteins are released by yeast autolysis, which affect the quality of the wines. The effect of mannoproteins has been extensively studied, and may affect aroma and foam quality. However, there are no studies on the effect of other polysaccharides such as those from grapes. Considering the large production of waste from the wine industry, it was proposed to obtain polysaccharide-rich extracts from some of these by-products[1].

Le monde vitivinicole est de plus en plus concerné par la question paysagère : l’enjeu est de taille puisqu’il s’agit de la survie de l’image positive dont bénéficient les Appellations d’Origine Contrôlée. Les paysages sont composés d’éléments qui renvoient à des références socioculturelles fortes, susceptibles de modeler l’image d’un produit et d’en déterminer à notoriété et le prix. Dans un monde médiatisé comme le nôtre, le visuel construit l’arrière-plan des représentations mentales associées à toute marchandise ; et pour les aliments, produits de la terre, ce visuel est forcément paysager.

This study aims at evaluating the effects of different refermentation methods (Martinotti/Charmat vs. Classic) on the chemical composition, aroma profile and sensory characteristics of Ribolla Gialla sparkling wines; furthermore, certain winemaking practices (skin contact and use of pectolytic enzymes) were investigated considering the extraction of varietal aromas and aroma precursors. METHODS: Sparkling wines were produced at pilot-plant scale. Concerning refermentation methods, traditional Martinotti (MB – 30 days length), extended Martinotti (ML) with 4 months of aging on lees and Classic method (CL) with 11 months of aging on lees were compared; in a second trial, skin contact (MM), enzyme addition on must also subjected to maceration (ME), and enzyme addition on base wine (VE) were evaluated. All experimental trials were performed in triplicate. Basic chemical composition, varietal (terpenes and C13-norisoprenoids in free and bound form) and non-varietal aroma compounds were evaluated by LLE-GCMS analysis; finally, sensory analysis was also performed, by descriptive testing.

3-Mercaptohexanol (3MH) is a volatile thiol occurring in several white and red wines, where it can contribute to fruity attributes. Its content is typically high in wines from certain grape varieties, in particular Sauvignon blanc, where it is considered a varietal marker. The strong nucleophilic character of thiols makes 3MH rather unstable during wine storage, due to the presence of several strong electrophilic species. Among these electrophilics, those arising from the oxidation of flavan3-ols such as catechin and epi-catechin have been indicated as critical for 3MH stability. Accordingly, there is a generalized interest towards the ability of vinification practices to reduce 3MH loss during aging through the management of wine flavan-3-ols content.