Diversificazione e valorizzazione di produzioni tipiche sul territorio: I cesanesi

Moscatel de Setúbal is a Portuguese fortified wine with Protected Designation of Origin (PDO Setúbal), made from Moscatel de Setúbal grape variety (Muscat of Alexandria) [1].

The tartaric stabilization of wines before bottling to avoid the precipitation of tartaric acid salts is an important and common step during wine production. The presence of precipitated salt crystals in bottle wines is detrimental for their quality and even a legal issue in some countries. Cold stabilization is the most common stabilization treatment. Although it has been shown to be effective, it has some significant disadvantages, mainly regarding losses of color and aromas and its high cost. Therefore, other products and methodologies are being introduced in the wineries for the replacement of this process. Some of these new techniques involve the reduction of the ions causing the insolubilization of tartaric acid while other are based in the formation of protective colloids or the inhibition of the crystallization of salts. In this study, white, rosé and red wines have been treated with carboxymethylcellulose, potassium polyaspartate and an ion exchange resin. The tartaric stability of the wines, together with the oenological, chromatic and sensory characteristics were studied after the wines had been stored during one year in the bottle. The results indicate that the use of carboxymethyl cellulose and potassium polyaspartate maintained the best the sensory and chromatic characteristics and the wine stability of the wines in comparison with an untreated control wine.

In grape berry pedicel, xylem hydraulic conductance can be impaired by blockage deposition in the lumen of xylem elements. However, the varietal difference of the interruptions has not yet been characterized. In this preliminary work, we utilized synchrotron x-ray computed microtomography experiments performed at MOGNO beamline (LNLS – Brazil) to identify possible blockage sites in natural grape pedicel xylem. For this, we imaged dehydrated pedicel’s stem portion from the Niagara Rosada variety in three different phenological stages (Pre-veraison (PreV), veraison (V) and post-veraison (PostV). The reconstructed tridimensional images with a voxel size of 1.16 µm were segmented for the identification of xylem vessel lumens. After analysing one pedicel stem per stage, we identified 658 vessels without occlusion throughout his axial plane and 41 in which we could identify possible interruptions.

Acidity adjustments are key to microbial control, sensory quality and wine longevity. Acidification with cation exchange resins -in acid cycle- offers the possibility to reduce the pH by exchanging wine cations, such as potassium (K+), for hydrogen ions (H+). During the exchange process, the removal of potassium and calcium ions contributes to limiting the formation of tartrate salts, thus offering an alternative solution to conventional methods for tartrate stability. Moreover, the reduction of wine pH and the removal of metals catalyzers (e.g. iron) could positively impact the wine’s oxidative stability. Therefore, the aims of this work were (a) to optimize the ion exchange process by testing different volumes and concentrations of sulfuric acid (H2SO4) during the acid cycle, (b) evaluate the effects of the ion exchange process on the formation of tartrate salts, and (c) analyze the oxidative stability of the treated wines.

Swiss wine producers are faced to high production costs and low-priced wine imports.