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Study of the Selected Types of Sulphur Compounds in Beer and Brewing Materials
Mikulíková, Renata ; Ventura, Karel (referee) ; Ventura, Karel (referee) ; Čáslavský, Josef (referee) ; Márová, Ivana (advisor)
Much attention has been recently devoted to sensorially active substances affecting beer quality in the Czech Republic and worldwide. Among them, the heterocyclic and sulphur containing compounds play an important role, some of them with high sensorial activity even in extremely low concentrations. Trace amounts of these compounds, which can be frequently found in foods, participate in formation of their aroma and this effect can be generally evaluated as favorable However, in malt or beer it is true only to a limited extent and the presence of heterocyclic and sulphur containing compounds are in this respect assessed rather unfavorably. The aim of the present study was to provide a survey about of problems in the field of sulphur containing compounds in barley, malt and beer, to describe metabolic paths leading to their formation and to verify experimentally possibilities of their determination using modern analytical methods. Sulphur-containing amino acids are a natural part of barley, malt and beer and are precursors of the origin of volatile sulphur substances. The most frequently occurring sulphur amino acids, metionine, cysteine and homocysteine, were selected for analytical monitoring. The method of gas chromatography was used to determine sulphur-containing amino acids in barley, malt and beer. Prior to the analysis, sulphur-containing amino acids were derived and volatile N(O,S)-ethoxycarbonyl propyl esters were formed; they were subsequently analyzed using the gas chromatography with mass detector (GC/ MSD) and the gas chromatography with flame photo detector (GC/ FPD). Direct analysis of sulphur volatile substances is possible only rarely as they are found in the analyzed matrices (malt, beer) only in very low concentrations ( g/kg,l - ng/kg,l). Before the analysis, the analytes must be extracted from the matrix and concentrated. The modern analytical methods SPME (Solid Phase Micro Extraction), SPDE (Solid Phase Dynamic Extraction) and TDAS (Thermal Desorption Autosampler) were experimentally compared for the extraction and subsequent concentration of sulphur volatile substances. The method of gas chromatography with flame photo detector was used to determine sulphur volatile substances. Following volatile sulphur substances were monitored: dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide, carbon disulphide, ethyl sulphide, diethyl disulphide, methionol, 3-methylthiophen, ethyl thioacetate, 2-methyl-1-buthanthiol. Only metionine was detected in significant amounts in the barley samples analyzed. Not only content but also dependence on a variety and locality were studied. Further, changes in methionine, cysteine and PDMS content during malting were followed. Results proved a significant decline in these substances content depending on the kilning temperature. Three types of fibers were tested for the analyses of the selected volatile sulphur substances in beer in the SPME method. PEG - a fiber with stationary phase Carbowax, PDMS - a fiber with stationary phase polydimethylsiloxan and a combined fiber CAR/PDMS - Carboxen and polydimethylsiloxan. Carbon disulphide, methionol, dimethyl sulphide, 3-methylthiophen and diethyl disulphide were detected with this method. Content of the other analyzed volatile sulphur substances was below the limit of detection. Further was tested usage the SPDE and TDAS methods. Both methods appear to be the suitable for the determination of volatile sulphur substances in beer.
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Taxing top income earners in the Czech Republic: an IDEA for reform
Dušek, Libor ; Šatava, Jiří
The study brings new facts about the distribution of top incomes and the taxation of top income earners in the Czech Republic, derives optimal marginal tax rates on the top incomes, and proposes a specific systemic reform. The top one percent of the highest paid persons in the Czech Republic include those employees and business owners whose gross incomes exceed CZK 1,230 million per year. By international comparison, the Czech Republic exhibits low inequality of gross incomes. The top 10% of the income distribution accounts for 25.7% of total income, whereas in all developed countries for which comparable data is available this figure is significantly higher, between 28.2% and 46.3%. When it comes to the top one percent of the income distribution, the discrepancy compared with other developed countries is less pronounced. The top one percent accounts for 6.8% of total income, while for comparable countries it is between 5.4% and 19.7%.
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Vyhodnocení současného stavu populace pajasanu žláznatého (Ailanthus altissima (Miller) Swingle) v Brně
Kovář, Roman
The bachelor thesis on the topic "Evaluation of the present-day state of the population of the Tree of Heaven (Ailanthus altissima (Miller) Swingle) in Brno" is divided into two parts, the theoretical and the practical part. The theoretical part deals with the issue of invasive tree species and its characteristics. The extensive chapter concentrates on the specific kind of the Tree of Heaven (Ailanthus altissima). Furthermore, it describes the area of interest and presents the results of observing the Tree of Heaven by other authors in Brno. The practical part is focused on mapping so far unmapped specimens of this derivative kind in the area of Brno-Černovice, on statistical evaluation of obtained data and finally on comparing the results with other authors.
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Leaf vegetable as a source of phenolic compounds with nutritional value.
TRÖSTLOVÁ, Daniela
The present work treats the amount of phenolic substances in salad plants. A part of this vast plant group is made of flavonoids, which are important by their accessibility and significant biological activity. Quercetin and rutin are in the main focus of this work. They are noted for their favourable biological effects. Having antioxidant qualities, they prevent and stop the lipid peroxidation and they dispose of free radicals. Flavonoids are used in medicine and can prevent the formation of chronic diseases, such as cardiovascular disease or atherosclerosis. The amount of phenolic substances in the chosen sample of ten salad plants was determined by means of micellar electrokinetic capillary chromatography (MECC) and by high-performance liquid chromatography (HPLC). We have used a freeze-dried material for the analysis. The utmost amount of quercetin was found in lettuce grown on outside garden. 48 600 mg/kg of dry matter highly exceeded the amount of quercetin in other plants. There were other phenolic substancs as well: rosmarinic acid, caffeoylchinol acid and caffeic acid. Among others, we found derivatives and colourants of caffeic acid as well.
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International Trade in Endangered Wildlife (including derivatives)
Bartůňková, Lenka ; Kašpar, Václav (advisor) ; Vošta, Milan (referee)
In the course of the 20th century the un-sustainability of international wildlife trade became apparent. European countries play a major role in wildlife trade. One third of total wildlife imports is destined to the EU which makes EU responsible for the protection of world wildlife and should motivate the EU to be a model in biodiversity protection. Regulation of wildlife trade in the EU is discussed in chapter 1. Trade in wildlife and its derivatives is among the most profitable branches of the international trade. Animals are traded in different forms. Birds are usually traded live (for the pet trade), mammals are traded for their fur, butterflies for their bodies, reptiles for their skins, the highest value is attained by trade in fish. In some categories (live birds, caviar) EU imports more than the rest of the world combined. The EU plays a major role as an importer in other categories as well. The magnitude, value and trends of international wildlife trade are discussed in chapter 2. Profitability of the wildlife trade, strong demand for some products and imperfect implementation of CITES result in the development of illegal trade. Illegal wildlife trade is dominated by organized criminal groups that also deal in drugs and human trafficking. Illegal wildlife trade is linked to severe risks and dangers to both the source country and the recipient. More on illegal wildlife trade in chapter 3. EU imports one third of all legally exported wildlife products. It is also the importer of a majority of illegal wildlife products. Having one of the highest standards of living and seeing that the care of environment cannot be limited by political borders, the author of this thesis concludes that it is logical and imperative that the EU engages in improvement of wildlife protection in less developed countries of the world. The last chapter deals with conservation of Cameroonian Dja Biosphere Reserve and with the attempt of large EU's environmental programs to improve conservation in Cameroon.
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Taxonomic variability tarsal glands of mammals.
HŮLKA, Martin
Tarsal glands or Meibomiena glands are sebaceous glands situated in the eyelids of mammals. These glands are important for visual abilities the eyes. The number of Meibomian glands and their morphology and location are often species-specific. Unfortunately, all our knowledges are derived from only several domestic animals and rodents, especially of arvicoline rodents. This thesis deals with the variability of other mammalian groups based on literature review and own results.
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Self-assembly and excited energy transfer in bacteriochlorophyll aggregates
Pospíšil, Petr ; Pšenčík, Jakub (advisor) ; Vácha, František (referee)
Bacteriochlorophyll c (BChl c) belongs among photosynthetic pigments. It is found in lightharvesting complexes of green photosynthetic bacteria in the form of self-assembled aggregates. It is possible to prepare BChl c aggregates also in vitro in aqueous solutions, in the presence of certain non-polar molecules (e.g. lipids or carotenoids). In this work, artificial light-harvesting antenna was prepared composed of BChl c and selected azulene derivative. The aggregation of BChl c with azulene enhances the absorption in the near UV region compared to BChl c. Fluorescence spectroscopy was used to study an efficiency of energy transfer from azulene to BChl c. The procedure used was based on fluorencence excitation spectra measurement, and a comparison with absorption 1-T spectra. The measurements were complicated by anomalous fluorencence of azulene, which occurs from the S2 state. Furthermore, the reference diode in the fluorescence spectrometer did not correct properly the signal in the near UV region, where azulene absorbs. The problem was partially solved by preparing the new correction files using selected laser dyes. Excitation spectra demonstrate the presence of the energy transfer from azulene to BChl c, however, it was not yet possible to satisfactorily quantify its efficiency.
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Energy metabolism of the Prague city
Fikar, Pavel
2 Abstract City is complex urban system. In human society city is biggest energy dissipative structure. Therefore it is important to understand how energy flows in to city, what main energy carriers are and what total energy requirements are. Prague was chosen as a model city for this case study. Prague is modern city, capital of the country housing, employing, accommodating and entertaining more than one and half million people daily. There are some significant differences between average country energy consumption and Prague energy consumption. Prague is touristic centre and destination of many travellers that come to country. Also Prague lack high concentration of heavy industry. There are very few electricity producers, most of time small entertainment or producers electricity from alternative fuels (e.g. central water treatment facility) and most of electricity is transported to Prague from other regions. Heat is produced from primary fuels centrally, but there is significant flow of heat through heat pipe from other regions. This diploma thesis presents results of the case study on Prague energy metabolism. There were accounted primary energy fuels (coal, oil, gas) as well as their derivates (e.g. fuel for cars driving in Prague) and final energy use. To do proper analysis of particular component of...
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Evaluation of activity of potentional antifungal substances through the use of microdilution broth method I.
Nitraiová, Jindřiška ; Paterová, Pavla (referee) ; Vejsová, Marcela (advisor)
1. Abstract Jindřiška Nitraiová Evaluation of activity of potentional antifungal substances through the use of microdilution broth method I Diplomová práce Univerzita Karlova v Praze, Farmaceutická fakulta v Hradci Králové Farmacie The aim of the thesis was a screening of activity of new potentional antifungal substances. For testing of substances was used the microdilution broth method. This method allows a routine assesment of MIC of a larger amount of antimycotics and also complete strains. The compounds for the strains Candida albicans, C. tropicalis, C. glabrata, C. krusei, Trichosporon beigelii, Aspergillus fumigatus, Absidia corymbifera a Trichophyton mentagrophytes were tested. The derivates of pyrazinedicarbamide, pyrazinedicarbothioamide, pyrazole-1- carboxylate, hydrazinecarboxylate, diazene-1,2-dicarboxamide and cyclohexanone did not show any antimycotic effectiveness. On the contrary the derivates of benzamide and benzenecarbothioamide showed a good antimycotic activity against all the testing strains. In the group of other substances, it means the derivates of pyrazinecarboxamide, pyrazinecarbothioamide, pyrazine-anilides, pyrazine-2-amine, pyrazine-2-carbohydrazide and pyrazine-2,5-dicarbonitrile and thiazolidine-4-one, some substances were effective but some had no effect. The derivates of...
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