Port wine region settling

Global climate change is exerting a notable influence on viticulture sector and grape composition. The increase in temperature and the changes in rainfall pattern are causing a gap between phenolic and technological grape maturities [1]. As a result, the composition of grapes at harvest time and, consequently, that of wines are being affected, especially with regards to phenolic composition. Hence, wine quality is decreasing due to changes in the organoleptic properties, such as color and astringency, making necessary to implement new adaptive technologies in wineries to modulate these properties in order to improve wine quality.

Vitis vinifera ‘Nebbiolo’ cultivar is a 3’-subsituted anthocyanin prevalent wine variety. It is grown in North-West Italy for the production of high quality ageing wines. In the present work berry skin anthocyanin amounts and profiles of the clones CVT 308, CVT 423 and CVT 142 were studied in 2004 and in 2005 in four environmentally different locations of North-West Italy: Donnas (steep mountain area), Monforte (hilly area, with a pH of 8.1), Vezza (hilly area, with a pH of 8.2) and Lessona (plain area, with a pH of 4.8).

Grapevine phenology has advanced across many regions, nationally and internationally, in recent decades under the influence of increasing temperatures, resulting in earlier
vintages (Jones and Davis, 2000, Petrie and Sadras, 2008, Tomasi et al., 2011, Webb et al., 2011. Earlier vintages have several ramifications for the wine industry. There are direct implications on quality, due to the fruit ripening during the hotter conditions of summer and early autumn, which then impacts grape composition and wine style (Sadras et al., 2013, Buttrose et al., 1971, Mira de Ordũna, 2010). There are also indirect implications where the fruit is perceived to ripen at a faster rate and the crop reach optimum maturity over a shorter period (Coulter et al., 2016).

Un paysage viticole est une relation entre des formes, dimension objective, et la perception que nous en avons, dimension subjective, émotionnelle. La viticulture n’est pas seulement productrice d’un vin, elle contribue également à façonner le paysage. Pourtant, jusqu’à présent, la connaissance des terroirs était principalement basée sur la caractérisation de leur aptitude à produire des vins de qualité.

Several classes of flavonoids, such as anthocyanins, flavonols, flavanols and flavones, undergo a slow H/D exchange on aromatic ring A, leading to full deuteration at positions C(6) and C(8). Within the flavanol class, H-C(6) and H-C(8) of catechin and epicatechin are slowly exchanged in D2O to the corresponding deuterated analogues; even quercetin, a relevant flavonol representative, shows the same behaviour in a D2O/DMSOd6 1:1 solution. Detailed kinetic measurements of these H/D scrambling processes are here reported by exploiting the time-dependent changes of their peak areas in the 1H-NMR spectra taken at different temperatures. A unifying reaction mechanism is also proposed based on our detailed kinetic observations, even taking into account pH and solvent effects. Molecular modelling and QM calculations were also carried out to shed more light on several molecular details of the proposed mechanism.