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Monitoring of the occurrence of mycotoxins in beers from market retail
Wawroszová, Simona ; Pospíchalová, Markéta (referee) ; Běláková, Sylvie (advisor)
This master thesis deals with monitoring of a content of deoxynivalenol, its metabolite deoxynivalenol-3-b-D-glucopyranoside and ochratoxin A in beer samples collected from retail market in the Czech Republic, Poland and Slovakia. The theoretical part describes general characteristics of mycotoxins, its transfer from field barely through malt to beer and its occurrence in beers. Malting process and brewing technology were also mentioned. Subsequently possibilities for a determination of the mycotoxins by the chromatografic and immunochemical method were presented. The experimental section describes analysis of 30 samples of beer. The analyses were conducted using ultra high-performance liquid chromatography with fluorimetric detection (UPLC/FLR) for ochratoxin A and high-performance liquid chromatography coupled with mass spectrometer (HPLC/MS) for deoxynivalenol and its metabolite. Ochratoxin A was detected in 25 of the 30 samples in concentration range of 0,6 - 82,5 ng·l-1. Deoxynivalenol was found in 24 of the 30 samples with concentration range of 2,29 - 12,57 ug·l-1 and deoxynivalenol-3-b-D-glucopyranoside was occure in 19 of the 30 samples in concentration range of 2,45 - 12,47 ug·l-1. It was also assessed the relationship between beer gushing and presence of mycotoxins in beer. No connection between the parameters has been found. Consequently it is not possible to predict beer gushing from the presence of mycotoxins.
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Microbrewery automation
Širůček, Pavel ; Matyáš, Pavel (referee) ; Marada, Tomáš (advisor)
Thesis discusses the basics of brewing technology, ingredients needed for beer production, homemade microbreweries, basic procedures and principles used in those breweries and their application. It also discusses the specific solution of selected microbrewery, its design, assembly and automation, including a description of the control software. Selected microbrewery consists of three containers, uses gas burner for heating and transfer pump for pumping. Programmable automatic PLC LOGO! program serves as a control unit of the microbrewery.
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Health effects of Czech beer
Bokrová, Jitka ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
The aim of this bachelor thesis was to study physiological effect of various kinds of lager beer and to compare these effects in Czech beer and several beers produced in foreign countries. In theoretical part Czech beer characteristics and biologically active compounds in beer are described. Quantification of total phenolics, total flavonoids, antioxidant activity and bitter substances was performed photometrically. The quantity of vitamin C was determined by high performance liquid chromatography with spectrophotometrical detection. Beer buffering capacity was analyzed by pH measurement in artificial stomach and intestinal liquid, respectively. Analysis of physiological effect was accomplished by analysis of proteolytic enzyme activity. The total of 22 samples (16 Czech and 6 foreign lager beers) was studied. In these samples levels of basic technological characteristics and buffering capacity were compared. Alcoholic and non-alcoholic beers were compared too. According to experimental data it was confirmed that consumption of Czech beer (mainly lager beer) positively influences digestion process and activity of digestive proteolytic enzymes.
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Minibrewery in Vyškov
Zvolský, Dalibor ; Rozehnal, Miroslav (referee) ; Štěpánek, Ladislav (advisor)
The master’s Thesis – Minibrewery in Vyškov, has a form of project documentation which contains relevant requirements according to valid regulations. The proposed building is situated on the plot number 2123/72 in the city Vyškov. It is a detached building which stands separately on the flat terrain. It is a two-storey building with partial basement. It is formed from three units – a minibrewery, a brasserie with kitchen and an administrative part. It is made of monolithic reinforced concrete frame, brick blocks with vegetative flat roof. The upper level attic gable is at the height of 8,880 meters. The seminar paper – minibrewery in Vyškov – is a part of the Master’s Thesis.
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Embedded System for Home Brewery Control
Mimochodek, Vojtěch ; Jaroš, Jiří (referee) ; Šimek, Václav (advisor)
This thesis is focused on automatic measurement of beer density during fermentation. The main objective is to create an electronic densitometer with a web user interface. The thesis consists of a theoretical part, which deals with the history of beer, beer production processes and equipment. The practical part includes system design and implementation. In conclusion, there are documented the results of testing the densitometer, which was the subject of the bachelor's thesis.
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Welding of pressure vessels
Máca, Martin ; Dohnal, Ivo (referee) ; Daněk, Ladislav (advisor)
The work is focused on the technology of welding pressure vessels. The chosen pressure vessel was one for beer fermentation (also known as CK tank). In addition there are methods of weld inspection and legislative rules for pressure vessels, also mentioned in this work.
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Effect of the dry hopping of the stability of beer foam
Benda, David ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the influence of dry hopping on the stability of the beer foam. It was observed how this effect affected general characteristics of beer, the content of hop bitter acids, proteins, phenolic compounds, selected micro- and macro elements, organic acids and the stability od the beer foam. Theoretical part characterises raw the materials for beer production, the substances affecting the stability of beer foam and the beer brewing process. Furthermore the beer foam is described froam a physical point of view together with the steps of its formation and drainage as well as other phenomena that lead to its disappearance. A detailed description of used analytical methods is included. The experimental part illustrates the preparation of the model beer and the implementation of dry hopping with the Czech hop variety called Kazbek. Dry hopping was carried out on day 3, day 5 and day 10 with a 3 g/l and a 6 g/l hop dose. The prepared beer was subsequently analysed for general characteristics, the beer foam stability, bitter hop acids, phenolic compounds, protein, selected micro- and macroelements and organic acids. Based on the measured data, there were found correlations between the observed beer parameter and the stablity of the beer foam. The results revealed that dry hopping in beer increases the content of the phenolic compounds and bitter substances, but its effect on the beer foam stability is negative.
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Bioflavouring of beer using new Czech hop varieties
Ondruch, Petr ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis focuses on bioflavouring of beer using new czech hop varieties. Dry hopping is a phenomem, that contributes to the attractiveness and diversity of beer and is nowadays gaining in popularity. The aim of this work was to determine the effect of dry hopping on sensory profile and analytical parametrs of dry-hopped beers using czech hop varieties. Sensory evaluation and chemical analysis of these beers were taken. The chemical analysis included determination of the basic beer characteristics, total phenolic a flavonoid content, antioxidant activity and the concentration of selected organic acids and chemical elements. It was found out that dry-hopped beers compared to the reference beer presented higher bitterness, antioxidant activity and contained higher amount of flavonoids. Also an increase in pottasium, manganese, copper, calcium and malic acid levels was reported. The pH of beer samples was not affected by dry hopping. Sensory evaluation showed that dry hopping had a positive influence on the overall enjoyment of the beer, which was mainly determined by the higher aroma and more intense bitterness. By summaring all the data, it is obvious that dry hopping of beer using new czech hop varieties has a positive effect on the quality of the final beer and these hop varities are suitable for further use in the beer industry.
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Characterisation of alcoholic beverages by means of spectrospic methods
Fajtl, Zdeněk ; Omelka, Ladislav (referee) ; Polovka, Martin (advisor)
The bachelor’s project is focused on the problem of determination of thermo-oxidative stability of mixed Radler - type drinks with low alcohol content. The project consists of both, theoretical and practical parts. The theoretical part describes the basic technological procedures used in the production of lager-type beer and also mixed drinks of Radler type. It also deals with the issue of antioxidants and/or oxidative processes with specific focus on beer and its components. The author also pays attention to spectroscopic methods, which are recently extensively applied to characterize different qualitative and quantitative parameters of foods; predominantly UV-VIS, IR and EPR spectroscopy. These methods were chosen with respect to the topic being studied. In the experimental part, the application of EPR spectroscopy and spin traps methods for the characterization of thermo-oxidative stability of the selected group of commercially available samples of Radler-type beer is presented. The values of the induction periods which were taken as a measure of thermo-oxidative stability, are compared, both for the group of Radler-type beers under study and for the commercially available samples of typical lager-type beers of identical producers, which were taken as for reference.
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Beer bioflavouring by dry hopping using czech cultivars of hops
Gajdušek, Martin ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the influence of dry hopping on selected analytical and sensory properties of beer. The effect of dry hopping was observed using Czech hop varieties Kazbek and Uran, which were added to the wort during the main fermentation phase in doses of 3 and 6 gdm-3. The contact time of hops with wort was 3, 6 and 9 days. The experimental part describes the technology of preparation of the reference beer, in which dry hopping were subsequently performed. A parallel measurement was performed on each sample. In terms of the basic parameters of beer, the effect of dry hopping, especially its length, on the ethanol content was observed. With a longer period of dry hopping, the concentration of ethanol in beer increased. The higher alcohol concentration was also associated with a decrease in the apparent extract. In terms of color and pH of beer, the effect of dry hopping has not been proven. Elemental analysis performed by optical emission spectrometry with inductively coupled plasma revealed an increase in the concentration of calcium, magnesium, and iron due to dry hopping. No statistically significant difference was observed for manganese and barium compared to the reference. In terms of bitterness, a significant increase was identified in dry hopped beers compared to the reference, the value being dependent on the dose of hops used. The effect of the hop variety has not been proved. Concentrations of organic acids determined by ion-exchange chromatography with a conductivity detector were affected by dry hopping only in the case of lactic acid and acetic acid. An increase in lactic acid was observed compared to the reference, also related to the degree of fermentation. While in the acetic acid content the hop samples showed a lower concentration than the reference sample. The concentrations of myrcene, humulene and geraniol were determined by gas chromatography with a mass detector. These are volatile components of hop essential oils. Dry hopped samples recorded significantly higher concentrations of all aromatic substances compared to the reference. In terms of hop time, the highest concentrations were shown by samples hopped for three days. The results of the sensory analysis show that the overall best rated sample is a sample hopped with the Kazbek variety with a dose of 3 gdm-3 for three days. Beer which was dry hopped for the shortest time also showed the lowest intensity of bitterness, which was perceived positively.
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