The polyphenolic components of wines have a very important role, especially as a consequence of the reactions that occur with other molecules that are present. An example is the reactions that take place during the traditional aging process on the lees or during the use of dry inactive yeast. These are both techniques that give several advantages both in sensory and stability aspects.
Fernando Zamora, describes in his presentation the results obtained during his research which aimed to understand the mechanisms behind the interactions that occur between the polysaccharides of these yeast and the phenolic compounds. In particular, he examined the effects that these interactions can have on the rough notes of certain tannins.
Various experimental trials were completed that helped study the kinetics of polysaccharide release, the quantity and the type, the mechanism of action and the sensory effect.
Another interaction which is well known is that between the phenolic compounds and the lactic acid bacteria. There are numerous studies on this subject, however many results are still ambiguous, mainly because of the great diversity found in phenolic compounds and lactic acid bacteria. In this study two aspects involved in this phenomenon were studied: the effects of enological tannins and of the phenolic compounds of different grape varieties.
The studies described by Aline Lonvaud-Funel tried to answer the following questions: do tannins used in winemaking have an effect on the growth and activity of Oenococcus oeni? Could the phenolic compounds of a wine explain the differences observed in the speed of the malolactic fermentation in wines with the same alcohol content, pH and total SO2? What differences are found between different grape varieties?
The seminars reproduced in these videos were presented at the 9th edition of Enoforum (Vicenza, Italy, 5-7 May 2015) in the session organized in collaboration with the company Lallemand
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