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Comparison of selected parameters of draft beers and lagers from breweries and microbrewery
HEJTMÁNKOVÁ, Zdeňka
The dissertation compares selected qualitative parameters beers on tap and lagers produced in large breweries and mini-breweries. The first part of the thesis briefly describes the basic raw materials for beer production. This is followed by a description of the production technology,which includes the production of malt and wort, fermentation and the finishing of beer. The practical part of the dissertation describes selected types of beer. Values obtained from a component analysis of beers are evaluated in tables and graphs. Individual beers are assessed mainly according to the alcohol content (% vol.). The difference between the microbrewery and large breweries was insignificant. The work includes sensory evaluation of selected samples. Taste, aroma, opacity, carbonation and bitterness of beers are assessed. The best rated beer in the sensory rating was Samson BOCK. From the mini-brewery Čtyrák 12 ° light premium lager beer was the best.
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The multiresidue determination of pesticides in barley and malt by the LC/MS method with QuEChERS extraction
Posoldová, Kateřina ; Pernica,, Marek (referee) ; Mikulíková, Renata (advisor)
The topic of this thesis is the determination of pesticides in barley and malt. Barley is one of the second most cultivated cereals in the Czech Republic. In order to achieve higher yields, higher grain quality, and avoid losses, plant protection products - pesticides - are used. The disadvantage of their use is their negative impact on human and animal health and the environment. Residues of pesticides and their metabolites can remain in a food, so it is a good idea to monitor their content. There are various options for determination, but recently the QuEChERS extraction method has been used, which speeds up the whole sample preparation process. The practical part summarizes the optimization and validation of the QuEChERS method and the subsequent quantification of analytes by UPLC-MS/MS. The content of 148 pesticides in 30 barley and 20 malt samples from the 2021 harvest in the Czech Republic was analysed.
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Arsenic determination in beer samples and raw materials for its preparation
Švadlenová, Veronika ; Hraníček, Jakub (advisor) ; Jelínek, Ivan (referee)
This thesis describes the optimization of the method for determination of arsenic by the chemical hydride generation coupled with AAS detection in beer samples and raw materials for its preparation. The beer usually contain arsenic at ultratrace level, however, it is necessary to monitor the concentration of this element in the beer. The routinely used method for determination of arsenic is determination by electrothermal atomization. This approach is time consuming, expensive and less sensitive. It has been developer suitable determination of arsenic as a faster and less expensive method. For this method there was optimized the flow rate of argon to 75 ml·min-1, the optimum flow rate for the reagents was 4.0 ml·min-1 and for the sample 5.0 ml·min-1 . 3 % NaBH4 in 0.5 % NaOH was used as the reducing agent for the determination of arsenic, and HCl diluted 1:1 with distilled water was used to acidify the sample. With this parameter LOD was 0.32 μg·l-1 and LOQ 1.05 μg·l-1 . It has been tested the arsenic determination in samples of barley, malt and potable water as beer raw materials. It has been found that the beer matrix is unsuitable for the hydride generation technique due to a stormy reaction in the gas/liquid phase separator. The effect of pretreatment, which is likely to enhance the effect of...
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Development of miniaturized extraction method used for GC-NCD screening of non-volatile nitroso compounds in malt
Malečková, Michaela ; Sobotníková, Jana (advisor) ; Kameník, Zdeněk (referee)
The aim of this diploma thesis was to develop a miniaturized extraction method for a fast screening of non-volatile nitroso compounds using gas chromatography with a nitroso specific chemiluminescence detection. According to a final methodology, the samples were prepared by extraction of grinded malt using a mixture of pyridine and acetonitrile in ratio 60:40 (v/v). To enhance volatility of the determined analytes, the two-step derivatization using hexamethyldisalazane and N,O-bis(trimethyl)-trifluoroacetamide was used. The total volume of the sample was 200 l and the preparation time after optimization was in total 80 min. The extraction method was connected to a classification method, which can divide chromatographic peaks into the groups of N-nitroso and C-nitroso compounds, and interfering substances. After application of the methods mentioned above to real malt samples, the specific chromatographic peaks of C-nitroso and N-nitroso compounds were selected. Description of their properties and structure suggestion will be a subject of the following study. Keywords Nitroso compounds, malt, extraction, derivatization, gas chromatography, chemiluminescence detector
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The Usage of Plasma Technologies to Improve the Quality of Feedstuffs
HAVELKA, Zbyněk
The dissertation thesis deals with the problems of the use of plasma technologies in agriculture for the purpose of improving the quality of feedstuffs for agricultural animals. The attention is focused above all on the use of low-temperature gliding arc plasma discharge generated by the atmospheric pressure for the elimination of model fungal pathogens (T. virens) and for the testing of the possibility of the use of plasma for the decreasing of mycotoxin load (DON and D3G). The professional orientation of the dissertation thesis is strongly interdisciplinary with the overlap to the area of the physics of plasma, microbiology, zootechnics and the proposal and construction of technical facilities. With that corresponds also the division of thesis into individual chapters. In the research part, there is a summary of actual pieces of knowledge from the area of fungal microorganisms and mycotoxins produced by these with the view on their presence in feedstuffs. There follows a research of pieces of knowledge of low-temperature plasma and its applications in the food industry and feeding. In the chapter Material and Methodology, the applicated methods of work, employed instruments and biological material are described. The resulting part is, for its clear arrangement, divided into five subchapters ? stating of selected parameters of plasma device, influence of plasma on nutritional parameters, influence of plasma on the model fungus Trichoderma virens and possibilities of the use of plasma discharge for the decreasing of concentration of mycotoxins in feedstuffs. The final part is dedicated to the description of system which enables the treatment of samples in continuous regime. The treatment of mycelial discs by plasma discharge lead to the decrease of germination capacity of spores of fungi, while there was experimentally proven the synergic effect of the influence of individual mechanisms by which the plasma interacts with the surface of biological material. At the same time, there was not observed a more significant change in the composition of feedstuffs, more significant is only the change of humidity of sample. In the laboratory conditions, the decreasing of concentration of mycotoxins spread on laboratory glass was proven. At the samples of feedstuffs contaminated by natural way, it was not successful to reliably provedecreasing of concentration of mycotoxins in a sample as a result of plasma activity.
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The yield formation of spring barley in depending on nitrogen fertilization
PECA, Tomáš
The theses presents results of experiments with spring barley started in years 2017 and 2018. The experiments were put into practice at Mr Jiří Nepovím's (BSc) place in Opatovice near Světlá nad Sázavou. Laudis 550 was used as the experimental variety of spring barley and the objective of the experiment was to observe the increasing amount of nitrogen and its effect on the resulting quantity and quality. The experimental amounts of nitrogen were set to 60 kg.ha-1, 75 kg.ha-1, 90 kg.ha-1, 105 kg.ha-1 and 120 kg.ha-1. With the increasing amount of nitrogen the crop increased of 0,2 - 0,4 t.ha-1. The share of nitrogen substances in grain increased of 0,2-0,5 %.
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Development of miniaturized extraction method used for GC-NCD screening of non-volatile nitroso compounds in malt
Malečková, Michaela ; Sobotníková, Jana (advisor) ; Kameník, Zdeněk (referee)
The aim of this diploma thesis was to develop a miniaturized extraction method for a fast screening of non-volatile nitroso compounds using gas chromatography with a nitroso specific chemiluminescence detection. According to a final methodology, the samples were prepared by extraction of grinded malt using a mixture of pyridine and acetonitrile in ratio 60:40 (v/v). To enhance volatility of the determined analytes, the two-step derivatization using hexamethyldisalazane and N,O-bis(trimethyl)-trifluoroacetamide was used. The total volume of the sample was 200 l and the preparation time after optimization was in total 80 min. The extraction method was connected to a classification method, which can divide chromatographic peaks into the groups of N-nitroso and C-nitroso compounds, and interfering substances. After application of the methods mentioned above to real malt samples, the specific chromatographic peaks of C-nitroso and N-nitroso compounds were selected. Description of their properties and structure suggestion will be a subject of the following study. Keywords Nitroso compounds, malt, extraction, derivatization, gas chromatography, chemiluminescence detector
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Enzyme content monitoring in wheat malt
Šubertová, Hana ; Benešová, Karolína (referee) ; Hartman,, Ivo (advisor)
The aim Master thesis was to evaluate the influence of malting technology on the content of hydrolytic enzymes -amylase and -amylase. Another aspect of this thesis was to select a wheat variety with the highest activity of enzymes -amylase and -amylase. The first part of the practical part of my work is shown measuring enzyme malt model varieties of wheat set (Triticum aestivum), where individual samples differ technological processing of malting and the second part is focused on the application of efficient malting conditions on other varieties from different locations in the Czech Republic in 2016 . All malt samples were analysed to -amylase and -amylase activity by assay Ceralpha method and Betamyl-3 method made by Megazyme company. After measuring the first part, the most effective malting condition was evaluated, such as a 7 day malting time, a 45% water content, a germination temperature of 18 ° C, and a drying temperature of 50 ° C. In the second part, the varieties are so malted and the highest content of enzyme -amylase was Rumor, it had averafe contanin -amylase 277 U/g, Bonanza – 255 U/g and Izzy –254 U/g. The biggest contain of enzymes -amylasehad varieties Matchball – 37,9 U/g , Fakir – 35,6 U/g, and Bernstein – 35,3 U/g.
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Monitoring of 3-MPCD content in barley, malt and beer
Šálková, Michaela ; Svoboda, Zdeněk (referee) ; Mikulíková, Renata (advisor)
The master’s thesis focuses on a process contaminant 3-MCPD (3-chloropropane-1,2-diol), which is formed during food processing. The first part of the thesis summarizes scientific knowledge about its chemical and physical properties, toxicity, occurrence in food and methods of analysis. In the second part is monitored the content of 3-MCPD in barley, in standard and special types of malts and beer. Samples were derivatized with phenylboronic acid (PBA) and 3-MCPD derivatives were analyzed by gas chromatography with a mass detector. Deuterated 3-MCPD was used as an internal standard. The limit of quantification was 1 gkg-1 for barley and malt samples and 10 gkg-1 in case of beer. The barley samples contained concentration of 3-MCPD below LOQ. In samples of malt was found concentration
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Influence of raw materials on qualitative indicators of various types of craft beer
HEJTMÁNKOVÁ, Zdeňka
Abstract The Bachelor's Thesis considers basic ingredients necessary for producing beer. In the first part, raw materials like hop, brewer's yeast, water, malt and its substitutes are dealt with. Regarding hop, the seed cone along with its chemical composition is discussed. Significant varieties grown in the Czech Republic are mentioned as well as selected foreign varieties of hop. Not least, packaging and storage of hop is described. Similarly with malt, where types of malt are listed and evaluation of quality given. The thesis contains also types of water suitable for producing beer. An indispensable ingredient for production of beer is brewer's yeast differentiated as top-fermenting and bottom-fermenting yeast. As an aside, the chemical composition and propagation of yeast is mentioned. In the last part, sorts of craft beer are discussed focusing on qualitative indicators of certain sorts of beer.
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