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Stabilizace barvy a zrání červených vín
Nesvatbová, Tereza
The bachelor´s thesis entitled: The stabilization and maturation of red coloured wine deals with the making of red wine and substances which are contained in it (anthocyanins and tannins). The thesis deals about the chemical structure of a grape, technology of red wine making and the stabilization of red coloued wine. Thesis also examines the processes of a maturation of red wine.
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Využitie enologických tanínov a chipsov pri výrobe vína
Stašová, Veronika
The final thesis copes with use of oak tannins and wooden chips during the red winemaking. The theoretical part is dedicated to characteristics and division of polyphenolic compounds. In this thesis there are also mentioned different types of tannins and oak chips, their extraction, usage and their impact on wine. Experimental part of the final thesis was focused on practical trial with two red wines and various additions of either oak tannins or wooden chips. One sample from each wine was left without any oak addition. At the end all wine samples were sensory evaluated,using 100 point system and tasters were also focused on structure and mightiness of the wines. Wines were accordingly analytically evaluated, where total polyphenols, catechins, antiradical activity, reducing power and amount of anthocyanins were determined.
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Využití enologických taninů při výrobě vína
Mikulica, Petr
The diploma thesis dealt with using oenological tannins in winemaking with research focus being on the Pinot Noir variety. The theoretical part describes the composition of phenolic compounds, classification and origin of tannins which can be found in wine. The practical part researches the use of ten commercially available tannins. The individual samples were evaluated by means of sensory analysis after four months. The assessment included aroma and structure profiles of given wine samples. The next step was the spectrophotometric analysis, which contained and assessed these analyses: total content of phenolic compounds, antiradical activity, total reducing power, total catechin content and total anthocyanin content.
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Biochemical changes accompanying the aging of red wine
Vacková, Tereza ; Hudeček, Jiří (advisor) ; Entlicher, Gustav (referee)
Flavonoids are plant secondary metabolites, which belong to several groups varying in their chemical structure. Anthocyanins and tannins are important flavonoid components of wine that are responsible for its color, taste and other sensory properties. The concentration of anthocyanins in wine is affected by grape variety, processing technology, and climatic conditions. In this Thesis, we studied the changes in color and in related chemical composition, using three non-commercial samples of red wine: Svatovavřinecké (year 2010 and 2012), and home-made wine (prepared without addition of SO2). These changes in color were determined using standard colorimetric method (CIELab) and also a simplified two-parametric spectrophotometric method (tint/color density). The content of anthocyanins was followed using analytical RP-HPLC method. In paralel, simplified oenologic methods for estimation of phenolic compounds were used. Generally the wine samples changed color to darker tint. Chemically, this was caused by polymerisation reactions between anthocyanins and phenolic compounds. This led to the formation of stable pigments characterised by a higher absorption maximum at longetr wavelength, hence a darker tint. Key words: anthocyanins, color, red wine, phenolic compounds, malvidin-3-glucosid, polymeric reactions,...
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Biochemistry of polyphenols effects in the treatment of vascular disease
Kondrashov, Alexey ; Štípek, Stanislav (advisor) ; Pecháňová, Olga (referee) ; Matouš-Malbohan, Ivan (referee)
This Ph.D. thesis deals with the deep analysis of polyphenols effects toward vascular disorders. This work provides a number of experimental results of studying both the effects of natural bioactive compounds in red wines and potatoes, and their application to the experiments which includes experimental animal models with spontaneous hypertension. Methods and equipment used in experimental studies allowed us to make several new statements regarding the universal nature of the relationships between the antioxidant capacity and the polyphenolic content in examined foodstuffs. Besides this it is also recognized that food is a source of minerals which also contribute to the total antioxidant capacity and therefore may have influence the endogenous antioxidant enzyme system by providing the essential cofactors. Experimentally we have found that the concentrations of magnesium known for its therapeutic action in wine and red wine extract are comparable to the mineral waters recommended for the treatment and prevention of cardiovascular and metabolic diseases. Moreover, synergistic interactions between selected minerals have been found. The key issue of bioavailability of polyphenols for supporting the idea of the beneficial effects of diet rich in fruits and vegetables toward vascular disease prevention...
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Determination of anthocyanins in selected kind of fruit
Forejtarová, Darina ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
Contents of this diploma thesis was introduction of method determination of anthocyanin pigments by liquid chromatography. Anthocyanin pigments was determined in various cultivars of elderberry (Sambucus nigra L.) and in selected samples of red wine. In the first part of the theory is described elderberry, its species and chemical composition. Some possibilities of processing and utilization of elderberry in medicine are mentioned here too. The next part of the theory is aimed at chemical agents in wine, characteristics of anthocyanins and their utilization in food processing industry. The methods for determination of anthocyanin pigments with focus on HPLC are also mentioned there. The main objective of the experimental part of this thesis was comparison of content of anthocyanins in various cultivars of elderberry and in selected samples of red wine. In samples of red wine was observed not only cultivars´ influence, but also influence of the crop year on the content of anthocyanin pigments. The separation of the anthocyanin pigments by high-performance liquid chromatography with diode array detection (HPLC/DAD) was performed. The highest content of anthocyanin pigments in elderberry was determined in the cultivar Haschberg. In the case of red wine, the richest source of anthocyanins was the cultivar André 2009 – Rakvice. Higher content of anthocyanins was explicitly proved in young wines rather than in older wines.
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Factors influencing the quality of red wine
Zechmeisterová, Lucie ; Vránová, Dana (referee) ; Omelková, Jiřina (advisor)
In my thesis, I focused on monitoring of microorganisms in the sample of red grape juice and on the interactions between yeasts, bacteria and filamentous fungi. Three different media were applied for the cultivation of microorganisms; firstly for monitoring of total volume of microorganisms, secondly for yeasts and third time for lactic acid bacteria. The indirect method was used for the determination of the amount of viable cells. This method consists in enumerating of visible macroscopic colonies grown up on agar plates. When the cells grew up, the forms of colonies were analyzed visually and the morphology of microorganisms was detected microscopically. The operating time of enzymes in grape juice in the production of red wine was monitored after application of commercial enzymatic preparation. The enzym action in grape juice was observed on the basis of the process of degradation of high – molecular substrate by enzymes through the use of Ubbelohd´s viscometer. The research findings provided a lot of knowledge about the occurance of microflora in the process of production of red wine. The commercial preparations added to grape juice played a significant role.
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Role kyslíku při výrobě červených vín
Stašová, Veronika
The bachelor thesis deals with the importance of oxygen at red wine production. The first chapter is focused on the importance of oxygen, its physically-chemical pro-perties and its importance in the field of viticulture. The second chapter describes ele-mentary compounds originated from grapes. The third chapter concentrates on possible occurrence of various types of oxidation and their influence on final organoleptic pro-perties of wine. The following part of the bachelor thesis describes modern technological procedures used at wine production. The final part is oriented on positive and negative effects of oxygen on wine during the aging process in different types of tanks and classification of wooden barrels.
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Flavonoidy a antioxidační aktivita červených vín
Vachová, Simona
The literary part of the thesis brings the insight into the issue of free radicals and their impact on the health of the organism. It deals with the specific abilities and the role of antioxidants in the protection against the negative impact of radicals. It also pays attention to flavonoids as major polyphenols in red wines which significantly influence the antioxidative activity, and thus the health benefits of wine. The practical part shows, using the spectrophotometric DPPH and FRAP methods, the comparison of antiradical activity and reducing power in selected samples of red wines made by different technologies of maceration. The results show the direct relationship between the maceration method and the measured values of the antioxidative potential of the red wines. The discussion and the final part of the thesis suggest new questions and possible directions for further research.
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