The effect of supplementation with three commercial inactive dry yeasts on the colour, phenolic compounds, polysaccharides and astringency of a model wine solution and red wine.

Background: Nowadays supplementing red wines with commercial inactive dry yeasts is a widespread practice in winemaking because it leads to better balanced wines through increased mouthfeel and smooth astringency. The aim of this article is to study, in a red wine and in a model wine solution, how supplementation with three commercial inactive dry yeasts affects chemical composition and astringency. This will give us a better understanding of the action mechanism involved.

Influence of grape maturity on the foaming properties of base wines and sparkling wines (Cava).

Background: The aim of this paper is to determine the main factors that influence the foaming properties of base wines and sparkling wines and, in particular, the role played by the maturity of the grapes in the controlled designation of origin (CDO) Cava. Macabeo, Xarel.lo, Parellada and Chardonnay grapes were harvested at two different maturity levels in two vintages.

Influence of grape maturity and maceration length on color, polyphenolic composition, and polysaccharide content of Cabernet Sauvignon and Tempranillo wines.

The aim of this paper was to study how maturity and maceration length affect color, phenolic compounds, polysaccharides, and sensorial quality of Cabernet Sauvignon and Tempranillo wines at three stages of grape ripening. Ripeness increased color extractability, phenolic compounds, and polysaccharide concentrations. Moreover, the proanthocyanidin mean degree of polymerization (mDP) and the percentage of prodelphinidins also increased with maturity, whereas the percentage of galloylation decreased.

Influence of wine pH on changes in color and polyphenol composition induced by micro-oxygenation.

The presence of oxygen in red wine leads to the transformation of ethanol into ethanal, which after capturing a proton will react with flavanols to start the process of forming ethyl bridges between flavanols and between flavanols and anthocyanins. Wine pH also conditions the equilibrium between the different anthocyanin structures and may thus affect anthocyanin reactivity. Consequently, the aim of this paper was to study how the pH can affect the changes induced by micro-oxygenation in two wines with different phenolic composition.

Comparison of methods for estimating phenolic maturity in grapes: correlation between predicted and obtained parameters.

With the aim of determining the real predictive ability of three methods for measuring phenolic maturity (Glories, ITV and Cromoenos), representative grapes of Merlot, Cabernet sauvignon, Grenache and Tempranillo were harvested at three different ripening levels. The grapes were vinified by triplicate and were also used for phenolic maturity estimation. After that, color intensity, CIELAB coordinates, anthocyanins by spectrometry and HPLC and total phenolics were analysed in wines and also in the different extracts from the three extraction methods.