Generally, the first sensory impression of a wine is visually perceived. Color, intensity, tonality,... gives us information about the elaboration processes, variety, ageing, oxidation and stabilization. The visual aspect predisposes us positively or negatively towards the product that we are going to taste.
From a technological point of view, the color can be favored (increased, improved) in two possible ways:
-Promoting the extraction and formation of pigments, or
-Avoiding their degradation in prejudicial stages.
The winemaker, thanks to his current technical knowledge, is the ultimate responsible of this task in the cellar, facilitating rack and returns and push downs, with the help of forming ethanol and the temperature rise.
However, the importance of the microbiological factor in this topic is scarce, or even unknown. The yeasts can influence the color of the wines modifying the concentration of anthocyanins, or favoring their precipitation. In addition, some species and/or strains potentiate the formation of new pigments of high stability, like the Vitisins A and B, the vinylphenolic adducts, and some polymeric pigments.
On the other hand, some biological ageing techniques, such as ageing on lees, preserve the anthocyanins monomeric content, due to its reducing effect on the medium, while certain cellular enzymatic activities of some yeast strains, such as B-Glycosidase, can accentuate the degradation of the color.
In this work some of these aspects are investigated.
Report presented at the Enoforum awards 2018. The paper reproduced in this video-seminar was presented at the 11th edition of Enoforum (Zaragoza, Spain, May 31 – June 1 2018)
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