Il ruolo dei comuni nella gestione del territorio e nella tutela dei vitigni autoctoni di qualita’

Les profils climatiques appropriés pour une activité photosynthétique optimale de la vigne sont déterminés dans différentes régions d’Afrique du Sud et localités à l’intérieur d’une région particulière.

Climate change establishes challenges, as well as opportunities for many sectors, and markedly the wine sector.

Elemental sulfur is a fungicide used by grape growers to control the development of powdery mildew, caused by the fungus Erysiphe necator. This compound is effective, cheap and has a low toxicity with no withholding period recommended. However, high levels of S0 residues in the harvested grapes can lead to the formation of reductive sulfur compounds that can impart taints and faults to the wine. Hydrogen sulphide (H2S) is a very volatile and unpleasant sulfur compound which formation is connected to high residues of S0 in juice (10 – 100 mg/L).

Approaching the notion of terroir wines at the level of consumption poses a problem due to the absence of a regulatory definition of the term terroir, which is not taken up either at Community level or at national level (the Consumer Code in particular does not define not the land). However, whatever definition is adopted for the terroir, we can retain at the consumer level an identification of the terroir through the different geographical mentions appearing on the labels or on the shelves of the wine shelf.

ulfur compounds in wine have been studied for several years due to their impact on wine flavour, but the role of polysulfides is a recent topic. Polysulfides in wine are formed when two sulfhydryl groups oxidize, especially in presence of elemental sulfur or metal catalysts from field treatment residues (Ugliano et al. 2011). These compounds are odourless, but can degrade during storage and affect the wine quality. The mechanism of their formation is still largely unknown but different chemical and biochemical pathways have been suggested. Disulfides from cysteine (Cys) and glutathione (GSH) have been revealed in model wines (Kreitman et al. 2016) and more recently also higher polymerized forms in real wines (Van Leeuwen et al. 2020). Volatile varietal thiols like 3-mercaptohexanol (3MH) and 4-mercaptopentanone (4MMP) – flavour compounds with tropical or fruity notes – could undergo similar reactions, also with Cys and GSH, subsequently losing their flavour property (fate). Even more concerning is the possible release of H2S from polysulfides during storage, leading to undesired off-flavours (Sarrazin et al. 2010).