Ripening potential of Touriga Nacional variety with different canopy management techniques and in different regions (Dão, Bairrada and Vinhos Verdes)

At CREA – Centro di Ricerca di Viticoltura ed Enologia, based in Velletri (RM), an experimental vineyard including 10 downy mildew resistent/tolerant grape varieties and two susceptible varieties was set up with the principal goal to evaluate the behavoir of these varieties in term of resistance to downy mildew (Plasmopara viticola). This evaluation, together to oenological studies, are necessary to register them also in Regional Register (in Lazio region). Monitoring of behavior towards Plasmopara viticulture of resistant vines were done in 2020 and 2021 at different times (phenological stages) and until harvesting, according to an international standard code BBCH a centesimal phenological scale, based on coding system.

Nemea region is the largest POD zone in Greece. Agiorgitiko (Vitis vinifera L. cv.) is the most cultivated variety in Greece with significant wine potential.

It is common to find tanks in the winery with wine below their capacity due to wine transfers between tanks of different capacities or the interruption of operations for periods of a few days. This situation implies the existence of an ullage space in the tank with prolonged contact with the wine causing its absorption/oxidation. Oxygen uptake from the air headspace over the wine due to differences in the partial pressure of O2 can be rapid, up to 1.5 mL of O2 per liter of wine in one hour and 100 cm2 of surface area1 and up to saturation after 4 hours.

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.

3-Sulfanylhexan-1-ol (3SH) is a key impact odorant of white wines such as Sauvignon Blanc.[1] In particular, the varietal characters of Sauvignon Blanc, especially from Marlborough New Zealand, are strongly influenced by the concentrations of 3SH.[2,3