|
|
Možnosti aplikace mastných kyselin při ukončení alkoholové fermentace
Černoch, Michal
This bachelor thesis deals with the issue of higher medium chain fatty acids (MCFA) and their effect on the termination of alcoholic fermentation. The literature describes fatty acids, carbonyl compounds, alcoholic fermentation and sulfur dioxide in general. In the experimental part, an experiment was carried out in which MCFA was applied and the effect on the end of fermentation and the content of carbonyl compounds was observed. The experiment was divided into two application variants. The main difference was that variant A was the applied MCFA to the wine lees, and wine was racked after three days, variant B then consisted in the application of MCFA immediately after racking of the wine. Chemical and sensory analysis was performered then. The effectiveness of MCFA in inhibiting microorganism was confirmed by chemical analysis. Within the total carbonyl compounds, the content was lower in variant B than in variant A but the difference was negligible. Compared to wines produced by standard technology, the wines where MCFA was applied the content was rapidly lower. Sensory analysis has shown that the recommended dose of MCFA does not affect organoleptic properties. The wines were fruity, with tones of citrus and tropical fruits.
|
|
|
Sledování sloučenin vázajících oxid siřičitý ve víně
Herzán, Jakub
The diploma thesis deals with observation of development of compounds that are able to bind sulfur dioxide. These are carbonyl compounds that are mostly product of yeast and bacteria metabolism. Theoretical part deals with sulfur dioxide, its characteristics and forms that are present in wine and it also deals with compounds that bind the sulfur dioxide. The diploma thesis also analyzes technology of production of wine by Sur-lie method and malolactic fermentation that enable reduction of SO2 in wine to the minimum value. The subject of research was to produce six types of wine from the same raw material with graduaded total dosage of sulfur dioxide. The experiment took six months during which was accomplished grapes processing, fermentation, three-month wine aging in stainless steel tanks, wine preparation for bottling, bottling and one-month aging in bottles. Throughout the whole experiment periodical samplings, evaluation of volume of carbonyl compounds and evaluation of individual forms of sulfur dioxide were realized. Basic analytical parametres of wines were determined and the wine was sensory evaluated.
|
|
|
Sulfur-based reagents for nucleophilic and radical introduction of tetrafluoroethyl and tetrafluoroethylene groups
Chernykh, Yana ; Beier, Petr (advisor) ; Kvíčala, Jaroslav (referee) ; Církva, Vladimír (referee)
Charles University in Prague, Faculty of Science Department of Organic Chemistry Ing. Yana Chernykh Sulfur-Based Reagents for Nucleophilic and Radical Introduction of Tetrafluoroethyl and Tetrafluoroethylene Groups Ph.D. Thesis Prague 2014 ABSTRACT This project was aimed at developing new methodologies for selective introduction of tetrafluoroethyl and tetrafluoroethylene groups into organic molecules. The study was focused on reactivities of fluorinated sulfones and sulfides as tetrafluoroalkylation reagents. In the Introduction part of the thesis, main aspects of organofluorine chemistry are outlined, illustrating beneficial effects of fluorine atoms on physical, chemical and biological properties of organic compounds. General synthetic methods for the selective introduction of fluorine atoms and fluoroalkyl groups to organic molecules are described. Particular attention is given to reactivity and applications of CF2CF2-containing compounds, indicating challenges in synthetic approaches toward tetrafluoroalkylation. The Results and discussion part describes reactivities of four new fluorinated organosulfur reagents as tetrafluoroethyl and tetrafluoroethylene building blocks. The application of these reagents as various carbanionic or radical synthons proved to be effective for the incorporation of CF2CF2...
|
|
| |
guest ::
