|
|
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.
|
|
|
Využití zeolitů v technológii vín révy vinné
Miklovičová, Kristína
This bachelor thesis has a theoretical-empirical character and its content is focused on the use of zeolites in the production technology of wine. The theoretical part defines the zeolite, its origin, composition and structure as well as the properties, the division of individual zeolites and their possible use in enology. This natural rock, characterized by their high absorption quality, is able to bind molecules to itself due to its porous structure. The empirical part analyses the effects of zeolites in the production technology of wine. Zeolite was applicated in the fermentation process of wine together with the yeasts. The experiment was performed with three variants of individual concentrations of zeolite and subsequently the sensory and chemical properties of wine were monitored. The experiment confirmed the reduction of thermolabile proteins after the application of zeolite, lower production of acetion and also lower concentration of polyphenol oxidase, thus preventing oxidation.
|
|
|
Vliv různých metod zákvasů révových moštů na jakost vína
Koubek, Jan
My thesis deals with various methods of fermentation of grape must. Describes unique methods of inoculation, yeast, alcohol fermentation, and terroir. A two-year experiment was made with samples of wines made from the same varieties. The difference in production was only the inoculation of the must. The other steps in wine making were the same, so that the only difference in the produced wine was the method of inoculation. The results obtained are clearly elaborated and evaluated, including aroma-profiles and wine profiles.
|
|
|
Obsah biogenních aminů v naturálních vínech
Kameníková, Zuzana
This thesis deals with the content of biogenic amines in natural wines. It compares the results of the sensory evaluation of the analyzed samples with the results of the chemical analysis of the basic parameters of the wine and with the results of the analysis of the content of biogenic amines. In the literature review, the chemistry and toxicology of these substances is described. The biochemistry of processes and the conditions under which they originate are explained in detail. Part of the review deals with the technical process of detection of biogenic amines. The experimental part describes the material and methods of determination of the sensory and chemical parameters. Both analysis are compared and statistically processed. The results show that biogenic amines are formed primarily by lactic acid bacteria and are found to be present in larger amount in wines that have undergone spontaneous malolactic fermentation. Based on these conclusions the propositions for future research and its applications in process of winemaking is made.
|
|
|
Možnosti snížení skutečného alkoholu ve víně
Bartoník, Jakub
The thesis was focused on the study of the possibilities of reducing alcohol in wine. For the first part of the experiment, a must of the Rhine Riesling variety was selected, which was put into eight 50-liter demijohns and inoculated with four different types of yeast purchased in a commercial network that were not modified. After completion of the fermentation process, when the residual sugar value was zero, a basic laboratory analysis of alcohol, residual sugar and acid values was performed. These wines were further evaluated sensory. The results of this experiment showed that commercially available yeast used for alcohol fermentation did not significantly affect the production of alcohol in wine. The wines produced showed similar alcohol values.
|
|
|
Použití nasycených vyšších mastných kyselin v technologii a skladování vína
Gočiková, Magdaléna
Efforts to reduce sulphur dioxide in wine have been the subject of wine interest for several years. Research over recent years has shown the effectiveness of saturated higher fatty acids as an alcohol fermentation inhibitor, even in the production of wine with higher residual sugar. The principle of the function of C8, C10 and C12 fatty acids is simple. They enter the body yeast, which subsequently change their structure and the cell will become permeable to other substances, and thus is not working - yeast stops working and alcoholic fermentation is stopped. The mixture of higher fatty acids of C8, C10 and C12 in the ratio 2 : 7 : 1 can during application of 10 mg.l-1 reduce the necessary dose of SO2 to several tens mg.l -1. The results show that administration of 10 mg.l-1 of a mixture of higher fatty acids in combination with 30-40 mg.l-1 SO2 is as effective as a dose of 60 mg.l-1 SO2 itself. In addition to the demonstrable effect of stopping alcohol fermentation, the HFA (resp. MCFA) mixture appears to be promising before referral (especially for wines with higher residual sugar).
|
|
|
Vliv různých metod zákvasů révových moštů na jakost vína
Koubek, Jan
My thesis deals with various methods of fermentation of grape must. Describes unique methods of inoculation, yeast, alcohol fermentation, and terroir. A two-year experiment was made with samples of wines made from the same varieties. The difference in production was only the inoculation of the must. The other steps in wine making were the same, so that the only difference in the produced wine was the method of inoculation. The results obtained are clearly elaborated and evaluated, including aro-ma-profiles and wine profiles.
|
|
|
Řízená fermentace pomocí sledování produkce oxidu siřičitého
Osička, Dominik
The bachelor thesis is concerned with the problem of controlled fermentation by monitoring carbon dioxide and sensory evaluation of three wines. These wines had different fermentation conditions. The theoretical part of the thesis is about alcoholic fermentation and its products. These part of text also describes biosensors and sensors use in oenology. The practical part includes a description of the variety Gewürztraminer. There are described a processes and methods of production of wines and a set of analytical and sensory methods which were performed. Results of individual wines are described in the end of work.
|
guest ::
