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Vliv autolýzy kvasinek na senzorické vlastnosti červeného vína
Hádlík, Martin
Bachelor thesis deals with yeast autolysis and its impact on wine properties, during wine training with the use of yeast lees. The first chapters deals with the description of red wine production, focusing on the major and by-products of alcohol fermentation. The following is a brief description of the malolactic fermentation. The next section deals with the yeast, their inclusion in the system, cell characteristics, life cycle and way of multiplication is described. Another chapters are devoted to the importance of yeast nutrition and description of the most used strains. The most important substances, that are produced by the yeast during the alcohol fermentation are described in the next chapter. The training of the wine and the proces of the bâttonage are explained in another part. Then, there are description of yeast autolysis, cell disintegration and substances that are released into the wine. The last chapter of the literary part deals with changes in wine during its ageing and focuses on selected substances and their development. In experimental part is briefly described selected grape variety and a there is a description of a experiment, that was made on this wine. The results discuss the conclusions we reached. There are graphs and tables with values from sensory and analytical evaluation, showing wine development during ageing.
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Studium vaznosti oxidu siřičitého ve vínech révy vinné
Andrusiów, Stanislav
The master thesis is focused on the bound sulfur dioxide, especially on its first dosage into the wine after the alcohol fermentation. The first part describes the properties of sulfur dioxide, its effects, bounds and dosing. Next it includes the theoretical background of sur-lie wine aging process in conjuction with the sulfur dioxide. The second part of the thesis was an experiment with the sulfur dioxide dosing into the wines right after the alcohol fermentation in comparison with sur-lie aged wines. The free sulfur dioxide was examined in the resulting wines. It was found out that sur-lie aged wines have a positive effect on redox potential and therefore on keeping higher free sulfur dioxide amounts which results in lower sulfiting dosages needed.
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Využitie metódy Sur lie pri výrobe bielych vín
Bažalík, Michal
Final thesis deals with research of exploitation of "sur lie" method in production of white wine. The focus is given on stability of wine, especially, stability against crystallization of tartrate salt acid in bottle, proteins stability and antioxidative nature of fine lees. First part of the thesis describes process of wine production by method of aging on fine lees. Composition of lees and cells of Sacharomyces cerevisiae together with its risks and benefits are illustrated in theoretical part. Experimental work monitored development of the wine stability in micro samples. The wine used for research purposes was variety of Silvánske zelené. Antioxidative capacity was monitored by FRAP method in the time of 16 weeks. Stability of proteins was measured by heat protein test and by turbidity meter. Content of tartrate salt was measured by filtration of samples and then weigh on laboratory scales. Sensory analysis was made by blind wine tasting degustation of professional commission. The results confirm higher protein stability which is about 30% more than in control sample. Risk of tartrate salt crystallization was reduced about 80 % in comparison with initial state. Antioxidative capacity of wine demonstrates slight decrease, but real required dose of SO2 added into wine was reduced. Key words: sur lie, bâtonnage, tartrate salt stabilty, antioxidative capacity, fine lees, mannoproteins, yeast cell, protein stability
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