La valorisation des Terroirs Viticoles par les Indications géographiques et les appellations d’origine

Terroir is not only a geographical site, but it is a more complex concept able to express the “collective knowledge of the interactions” between the environment and the vines mediated through human action and “providing distinctive characteristics” to the final product (OIV 2010). It is often treated and accepted as a “black box”, in which the relationships between wine and its origin have not been clearly explained. Nevertheless, it is well known that terroir expression is strongly dependent on the physical environment, and in particular on the interaction between soil-plant and atmosphere system, which influences the grapevine responses, grapes composition and wine quality. The Terroir studying and mapping are based on viticultural zoning procedures, obtained with different levels of know-how, at different spatial and temporal scales, empiricism and complexity in the description of involved bio-physical processes, and integrating or not the multidisciplinary nature of the terroir. The scientific understanding of the mechanisms ruling both the vineyard variability and the quality of grapes is one of the most important scientific focuses of terroir research. In fact, this know-how is crucial for supporting the analysis of climate change impacts on terroir resilience, identifying new promised lands for viticulture, and driving vineyard management toward a target oenological goal. In this contribution, an overview of the last findings in terroir studies and approaches will be shown with special attention to the terroir resilience analysis to climate change, facing the use and abuse of terroir concept and new technology able to support it and identifying the terroir zones.

One of the main sensory characteristics of red wine is astringency, which can be defined as drying, puckering and roughing of the oral cavity after the exposure to tannin-rich wines. Tannins are the main responsible for the intensity of the sensation as well for the qualitative aspects of astringency. However, the total intensity of the sensation is not sufficient to fully characterize red wine astringency. Thirty-three different subqualities (Gawel et al. 2001) had been generated to describe the complexity of this multi perceptual phenomenon, which includes both tastes, tactile, and flavor sensations. So, how to feel tannins during tasting? In this study, we used a sensory method that combine the training for astringency subqualities with touch-standards and the CATA questions, usually applied in consumer science, to evaluate the astringency subqualities of different typologies of Sangiovese: commercial and experimental wines. Sangiovese wine represents a good model for the study of astringency because it is generally characterized by a high content of low and high molecular weight proantocyanidins. Commercial wines differed for percentage of Sangiovese (80-100 %) grapes used in winemaking and for designation (Toscana TS, Chianti Classico CH, Chianti Riserva CR, Morellino di Scansano MS). The astringency profile of wines changed as the percentage of Sangiovese increased. Positive subqualities as velvet, soft, mouthcoat, and rich highly characterized the Sangiovese wine belonging to TS and CR designations. Moreover, the astringency subqualities related to blending or wood aging, represented the drivers of quality of commercial Sangiovese wines.

Gum arabic is composed of a polysaccharide rich in galactose and arabinose along with a small protein fraction [1, 2], which gives its stabilizing power with respect to the coloring substances or tartaric precipitation of bottled wine. It is a gummy exudation from Acacia trees; the products used in enology have two possible botanical origins, i.e. Acacia seyal and Acacia senegal, with different chemical-physical features and consequently different technological effects on wines. The aim of this work is to evaluate the feasibility of discrimination of commercial gums Arabic between their two different sources, on the basis of the absorption of the Fourier Transform Infrared (FT-IR) spectra of their aqueous solutions, in order to propose an extremely rapid and cost-saving method for quality control laboratories.

The use of glutathione (GSH) in winemaking has been legitimated recently, according to OIV resolutions OENO 445-2015 and OENO 446-2015 a maximum dose of 20 mg/L is now allowed to use in must and wine. Several studies have proven the benefits of GSH, predominantly in Sauvignon blanc. Thus, oxidative coloration of must and wine is limited, aroma compounds such as volatile thiols are preserved, and the development of ageing flavors such as sotolon and 2-aminoacetophenone is impeded. The protective effect may be explained by the high affinity of GSH to bind o-quinones which are formed during phenolic oxidation and which are known to initiate browning and other oxidative changes. Some researchers have proposed the hydroxycinnamic acid to GSH ratio (HGR) as an indicator of oxidation susceptibility of must and could show that lower ratios yielded lighter musts.

Over the last years, due to climate change, several red wines, such as the Sangiovese wines, have been often subjected to loss of clarity due to the formation of deposits of fine needle-shaped crystals. This phenomenon turned out to be due to an excess of quercetin (Q) and its glycosides (Q-Gs) in wines. These compounds are synthesized to a large extent when grapes are excessively exposed to UVB radiations in vineyards[1]. Unfortunately, it is not easy to predict the degree of Q precipitation because its solubility strongly depends on the wine and matrix composition[2].