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Influence of spontaneous and inoculated fermentation on the organic acid content in wine
Křižánková, Hana ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
Diploma thesis deals with the problem of observation of controlled and spontaneous fermentation influence on the organic acids content in species of wine (Ruland blue) originated in subregion of Velké Pavlovice. Initial conditions of analysis (introduced in [41] and in materials concerning chromatographic column) were changed during lasting of experiment in such manner to get the most precise analysis of the wine sample. Enzyme Rapidase Excolor was added in the beginning of both types of fermentation plus yeasts were added at the controlled fermentation. Analysis of four organic acids was done; these were tartaric, malic, lactic and citric acid. High performance liquid chromatography (HPLC) with UV detection method was used to determine concentration of each acid. Wine was processed by two technological methods – by spontaneous and controlled fermentation. Each of the process differed in the organic acids content. Concentration of tartaric acid varied from 1,63 g/l to 6,43 g/l during spontaneous fermentation process. Decrease was caused by biological processes taking place. Concentration of citric acid was not almost influenced by the process of fermentation. Due to malolactic fermentation being in progress, decrease in malic acid concentration (from 6 g/l to 1,87 g/l) and increase in lactic acid concentration was observed. Concentration of tartaric acid varies as well during controlled fermentation. Biggest increase in concentration was observed at hour 214 of the experiment when the process of fermentation was supported by addition of lactic bacteria. Due to malolactic fermentation being in progress, decrease of malic acid concentration and increase of lactic acid concentration was observed similar to simultaneous fermentation. Concentration of citric acid was constant during controlled fermentation. Experiment proved that there is higher content of observed organic acids during controlled fermentation than during processes of spontaneous fermentation.
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Možnosti regulace kyselin v hroznových moštech a vínech
Pribilová, Lenka
The aim of this thesis was to describe the selected organic acids in wines and musts . The most important acids in grapes are tartaric acid and malic acid . Then describe the physiological characteristics of the grapes ripening affecting acidity . According to them, it is possible to determine exactly when in the vineyard may apply specific agro-technical interventions . Although there is a quality wine in the vineyard , it is very important technological processing . In grades where there is non-ideal malic acid and tartaric acid in musts and wines is applicable regulation acids , increasing or decreasing acidity. Acidification can be achieved by means of tartaric acid , lactic acid and citric acid. Conversely common acidification can be de-acidified using blending wines , hydrogen carbonate calcium and other conventional methods or modern viticultural biodegradation acids , which are in sharp taste degrade malic acid to softer lactic acid .
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Malolaktická fermentace a možnosti načasování inokulace mléčnými bakteriemi
Hasil, Radim
This thesis deals with the malolactic fermentation and the accuracy of timing of lactic acid bacteria inoculation. The literary part deals with the bacteria malolactic fermentation, its controlled form, description of lactic acid bacteria and their time of inoculation into wine and advantages and disadvantages of this operation. The practical part is based on the methods of malolactic fermentation and inoculation of lactic acid bacteria after alcoholic fermentation in to wine and sensory evaluation of resulting products.
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Kyseliny v hroznech a vínech a jejich vliv na kvalitu vín
Zatloukalová, Magdaléna
The Bachelor thesis was written in Lednice on Department of Post-Harvest of Horticulture Products, in Faculty of horticulture at Mendel University in Brno in 2014. The literary part describes physiologic processes of grape ripening and also individual organic acids in grapes and wines and possibilities of their treatment. The experimental part deals with the impact of selected acids on overall acidity and taste of wine. In the evaulation of the overall intensity of acidity in both concentrations appeared less intense samples with the addition of tartaric acid and lactic, smaples with malic and citric acid seemed to the evaluator to be sourer. In the evaulation of the overall taste was as the most pleasant sample marked the one with tartaric acid. Least tasty become samples with addition of citric acid and malic acid.
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Analysis of organic acids by a novel procedure of extractive derivatization in human plasma and serum by GC/MS
JAHODOVÁ, Lucie
The theme of the bachelor{\crq}s thesis was ``The Analysis of Organic Acids by New Extractive Derivatization Process in Blood Plasma and Serum Using the GC/MS Technique{\crqq}. The objective of the thesis was to develop a method for fast determination of organic acids by a new process of extractive derivatization, to identify and determine organic acids in body fluids, to compare their abundance and to evaluate the possibility of implementation of this method in clinical diagnostics. Body fluids contain hundreds of organic acids, which co-create a clinical picture of a patient{\crq}s health condition. The current research focuses on implementation of methods providing for comprehensive, metabolism-based analysis of these metabolites important from the point of view of diagnostics. Nowadays, an analyst can select from a wide range of methods and several effective analytical and separation techniques for separation, determination and identification of organic acids in complex biological matrices. In the introductory, theoretical part of the bachelor{\crq}s thesis, the knowledge of properties of organic acids and possibilities of their determination are summarized. In the practical part, the method of fast determination of organic acids in body fluids by the GC/MS techniques was developed. By means of this technique, it is possible to analyze large quantities of organic acids in minimum volume of body fluid. Derivatization of a set of several tens of organic acids with ethyl chloroformate in aqueous medium was carried out. The reaction proceeds very fast and at laboratory temperature. The applicability of the developed method was verified through analysis of organic acids in biological samples. In samples of blood serum and plasma, tens of organic acids were identified by means of the above-mentioned method, retention data and EI mass spectra. Experiments performed for the purpose of this thesis proved that derivatization with chloroformates in aqueous medium is a relatively simple, fast and promising method for analysis of organic acids. Follow-up experimental research is necessary to make the methodology applicable in clinical diagnostics and to define advantages and limitations of this new methodological procedure.
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