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Studium technologie výroby vín typu "ryšák"
Štefanov, Martin
The submitted thesis was focused on the study of redhead wines. In the experiment, wines of the redhead type were made using the technology of mixing of must and mixing of mash. For both variants, wines with different proportions of white and blue varieties were created. It was a variant of 75 % of the white variety to 25 % of the blue variety, 50 % of the two varieties and the third variant was 25 % of the white variety to 75 % of the blue variety. Pinot Blanc variety was used for the experiment for a white varieties and the Zweigeltrebe variety was used for the experiment for blue varieties. It also produced classic white and red wine from the varieties. Sensory analysis was performed on wines. Basic analytical parameters (alcohol, titratable acids, reducing sugars, pH and glycerol), antiradical activity and phenolic compounds (anthocyanins, flavanols, flavonols, hydroxycinnamic acids) were also measured. The results show the fundamental impact of maceration of the solids of the berries on the resulting wines, followed by the influence of the variety used. Wines produced by maceration of mashes contained higher values of phenolic substances than wines produced by fermentation of musts.
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Vznik vyšších alkoholů ve víně
Štefanov, Martin
The aim of this bachelor thesis is to investigate higher alcohols, mechanism of their formation and also factors, which have influence on formation processes. The presented thesis contains a list of the most significant higher alcohols present in wine together with their physical and chemical properties and their effect on organoleptic wine characteristics. The main part of this thesis focuses on the origin of those higher alcohols in wine. Thesis analyses in detail both possibilities of higher alcohols formation. First possibility is represented by catabolism of amino acids, also known as the Ehrlich s pathways. Second possibility is represented by biosynthesis of amino acids. Both mentioned processes intersect at point of the alpha keto acids. For understanding the formation of higher alcohols is essential to reveal the system of both reaction types. The issue is that those enzymatic reactions are significantly dependent on genomes encrypting the formation of individual enzymes. For the formation of higher alcohols is important, except for the genetic equipment of yeast cell strains, to supply must with nitrogen. The condition of fermentation is then influenced by forms of nitrogen, must aeration, fermentation temperature and other factors
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