The role of yeast derivatives in the activation of alcoholic fermentation is well known. However, the lack of knowledge about the composition of these products makes their use essentially based on empirical criteria and their effects difficult to evaluate at the wine cellar level.
After a brief introduction on the definition, the production criteria and the characteristics of the different types of yeast derivatives, Piergiorgio Comuzzo presents the work done in order to clarify the relationships between their composition and the effects on the course of the AF and on the chemical and aromatic characteristics of the wines.
The tests were conducted on nine commercial products (inactivated yeasts, yeast hulls and autolysates), studying in particular the impact of the various components (reduction of fatty acids, absorption of volatile esters, nutrition, interaction with the aromas of wine, protection of the colour), the influence of production technology on each of them and the importance of the dose and the time of the dosage.
In the second video, Federico Giotto highlights the decisive role played by the process of lysis, inactivation and dehydration of yeasts that was able to be optimized through the development of an innovative process at low temperatures. He then analyzes the potential of the inactivated yeasts showing some application examples: the use in musts and during refinement and conservation, the effect on the aroma and taste of the wines, the interest during the clarification with bentonite, the action on pinking, the improvement of the quality of the foam during the sparkling process and the impact on red wines.
Finally, Gianmaria Zanella describes the products derived from the innovative X-PRO inactivation process that fully preserves the characteristics of the yeasts, carried out at low temperature, under vacuum and without the use of exogenous enzymes.
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The papers reproduced in these videos were presented at the 12th edition of Enoforum (Vicenza, 21-23 May 2019) within the module organized in collaboration with Enologica Vason.