National Repository of Grey Literature 118 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Coproduction of polyhydroxyalkanoates and violacein employing members of the genus Janthinobacterium
Uhrová, Kateřina ; Mravec, Filip (referee) ; Obruča, Stanislav (advisor)
This bachelor's thesis deals with the study of appropriate conditions for the cultivation of bacteria of selected genera Janthinobacterium, specifically strains CCM 160 and CCM 1888 and the genus Iodobacter fluviatilis strain CCM 3308 from the Czech collection of microorganisms. The most suitable conditions for bacterial growth were investigated. The aim was to identify ideal production medium, cultivation volume, temperature and conditions in the form of submerged and static cultivation. At the same time, one of the strains used was chosed, which appeared to be the best producer of metabolites. Production of the purple pigment violacein and polyhydroxyalkanoates (PHA) was observed during the cultivations. Violacein was extracted using methanol and the concentration of the produced violacein content was measured using UV/VIS spectrophotometry. The PHA content was determined using gas chromatography. The obtained data were compared with each other and it was determined whether the production of both metabolites is mutally affected. Furthermore, cultivation on a solid carrier was carried out, which proved more effective in the production of violacein than in a liquid medium. This type of cultivation could in the future lead to the commercial production of violacein, which has a number of positive properties. The 16S rRNA and phaC genes were detected using the multiplex PCR method.
Technology for the production of wine sausage with the addition of cheese
Kejmarová, Anna ; Nábělek, Jakub (referee) ; Mikulíková, Renata (advisor)
The aim of the bachelor thesis was to investigate the effect of soft cheese on the organoleptic properties of wine sausage. Samples of wine sausages were taken before and after baking and the percentage of lipids in the sample and the content of individual fatty acids were determined using the analytical method of gas chromatography. The sensory analysis was divided into two parts. In the first part, the evaluators assessed the appearance, aroma, consistency, texture, taste, overall evaluation and balance of the cheeses. The second part focused on the overall evaluation and selection of the most flavourful samples. The data obtained from the sensory analysis were processed and evaluated using Excel. The most unpalatable wine sausage, from the results of the sensory analysis, was the wine sausage with ermine.
Lipid and fatty acid content depending on the barley variety
Havlíková, Michaela ; Pernica,, Marek (referee) ; Svoboda, Zdeněk (advisor)
The bachelor thesis deals with the evaluation of the influence of barley variety on lipid content and fatty acid profile. Samples of barley and malt from the 2022 harvest, seven varieties recommended by Research Institute of Brewing and Malting, Plc. for the production of beer with the protected geographical indication ,,České pivo“, were analysed. The theoretical part of the thesis characterizes lipids and fatty acids, describes their occurrence and importance in barley grain, describes the changes associated with them during the technology of malt and beer production and how these changes can affect the final quality of beer. The possibilities for the determination of lipids and fatty acids are given and attention is paid to the determination of the fatty acid profile by using the method of gas chromatography. In the experimental part, lipids were extracted from barley grains and malt by fluidized bed extraction method using the fexIKA® dive-in control extractor. The extracted lipids were transesterified into methyl esters of the corresponding fatty acids, which were analysed by gas chromatography with flame ionization detection on a SLB-IL 100 capillary column. In both barley and malt were identified eight fatty acids as their methyl esters. The predominant fatty acid was linoleic acid. Reduction of total lipid content and change in fatty acid profile due to the malting process were observed.
The usage of the "Ethanol as internal standard" method for the SPME-GC/FID analysis of volatile compounds in alcoholic products
Zavoralová, Lucie ; Korban, Anton (advisor) ; Sobotníková, Jana (referee)
This bachelor thesis dealt with the optimization of a method for the determination of 10 volatile compounds occurring as minor components in alcoholic products. The quantification was performed by the internal standard method, comparing the results using 1-pentanol and ethanol as classical and proposed internal standards, respectively. In the case of ethanol usage, better repeatability and accuracy of the results were expected as this method does not require any sample pre-treatment. The optimized measurement method was monitored for both internal standards, while following these parameters - repeatability, recovery, linearity and limits of detection and quantification. It was found out that, as expected, the method of the proposed ethanol internal standard gives more accurate results for the analysis of real alcoholic beverage samples. However, it did not outperform the classical internal standard method in all parameters. That one gave better results for repeatability and linearity for the set of calibration solutions measured, despite the fact that each sample had to be pre-treated. It was also found that samples with a high ethanol or other volatile content were not suitable for SPME analysis, because the fibre then loses its ability to sorb these substances in the same proportions and...
Optimization of nontargeted analysis of beer by gas chromatography with mass spectrometry
Růžičková, Hedvika ; Vrzal, Tomáš (advisor) ; Korban, Anton (referee)
A non-targeted analysis of beer samples was carried out using dispersive liquid-liquid microextraction (DLLME) and gas chromatography with mass spectrometric detection (GC-MS). The method was optimized in terms of the composition of the reaction mixture and the type of dispersing agent used. One sample of alcoholic beer was used for the optimization. The processed data showed that the optimal arrangement of DLLME for non-targeted analysis of beer is a reaction mixture consisting of 1 ml of the sample, 300 µl of the extraction agent (chloroform), and 700 µl of the dispersing agent (ethanol).
Determination of essential oils in hops and beer by GC-MS method
Přikryl, Jaroslav ; Sobotníková, Jana (advisor) ; Nesvadba, Vladimír (referee)
The submitted master's thesis aims to the analysis of hop essential oils using gas chromatography separation and subsequent determination using a pair of mass and flame ionization detectors. In the first part, the thesis focuses on the theoretical approach to the issue of hop essential oils and the technical functionality of the device for the detection and quantitative determination of essential oils. Subsequently, in the second part, work describes the development, optimization and validation of the newly developed method for the extraction and determination of hop essential oil.
Extension of artificial intelligence DeepReI and its application in practice
Hurychová, Nikola ; Sobotníková, Jana (advisor) ; Křížek, Tomáš (referee)
Diploma thesis deals with expanding the artificial intelligence DeepReI with the prediction of retention indices of substances in gas chromatography for standard non-polar and polar stationary phases. The theoretical part describes artificial intelligence, convolutional neural networks, and the principles of neural network learning. There is also a brief overview of the applications of neural networks in analytical chemistry. In the experimental part, the original DeepReI model was extended to predict the retention indices of substances for standard non-polar and polar stationary phases. Furthermore, more accurate predictions of retention indices were achieved for semi-standard non-polar stationary phases compared to existing models. The applicability of the model for substance identification was verified through non-targeted analysis of non-alcoholic beers using gas chromatography with mass detection.
Determination of volatile and non-volatile nitrite products in sausages
Hlávka, Jan ; Sobotníková, Jana (advisor) ; Čabala, Radomír (referee)
This diploma thesis deals with the determination of nitrite products in sausages using gas chromatography. In the first part of this thesis, an extraction method was developed for the determination of 4-cyanophenol and N-nitrosoproline in samples of sausage products using gas chromatography with tandem mass spectroscopy. A 1% formic acid solution in acetonitrile was used to extract the analytes from the sausage samples. Due to the lower volatility of the analytes, derivatisation with N,O-bis(trimethylsilyl)trifluoroacetamide was necessary before each analysis. Using this method, an indicative determination of the concentrations of 4-cyanophenol and N-nitrosoproline in selected sausage samples was carried out. The standard addition method was used for the quantification of these analytes because of the strong matrix effect. For the selected types of sausage, it was observed whether or not the concentrations of the analytes differed in products with different meat contents. At the end of this diploma thesis, a validation of a method for the determination of volatile N-nitrosamines in sausage products by gas chromatography with chemiluminescence detection was performed. The analytes were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine, N-nitroso-piperidine, N-nitrosopyrrolidine...
Phytochemical studies of potential phytopharmaceuticals using separation methods
Dulendarova, Elizabeta Hristiyanova ; Jenčo, Jaroslav (advisor) ; Křoustková, Jana (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department: Department of Pharmacognosy and Pharmaceutical Botany Candidate: Elizabeta Hristiyanova Dulendarova Supervisor: RNDr. Jaroslav Jenčo, Ph.D. Title of dissertation thesis: Phytochemical Studies of Potential Phytopharmaceuticals using Separation Methods The main aim of this diploma thesis was the identification of main alkaloidal components from the fraction of Papaver rhoeas L. (family Papaveraceae) alkaloidal extract - fraction PR-12-23. The introduction to the theoretical part summarizes alkaloids found in Papaver rhoeas L. and describes the separation methods used in the isolation process at the department of Phamacognosy and Pharmaceutical botany. Two main compounds within the extract were identified and separated based on HPTLC, HPLC-MS, and GC-MS chromatographic separation methods. For the subsequent fractions, the HPLC method development, optimization, and scaling up from analytical to preparative scale was done. After identification with the help of analytical HPLC and GC, the compounds were separated into fractions, isolated using preparative HPLC, and identified using NMR. The purified isolates were tested for anti-butyrylcholinesterase and cytotoxic biological activity, linked to AD and cancer, respectively. The first...
Microbial production of lipids and their applications
Kročianová, Natália ; Szotkowski, Martin (referee) ; Němcová, Andrea (advisor)
The aim of this bachelor's thesis was the production of lipids by selected strains of yeasts of the Metschnikowia genus using food production substrates. Produced microbial lipids are nowadays highly valued and sought after mainly in the biotechnology industry as a substitute for carbon in the industrial process of biofuel production. Plant, ecological, and cost-effective substrates were used for cultivation ; the influence of cultivation conditions on the growth of yeast was monitored at laboratory and reduced temperature. Four types of yeast were investigated, namely M. pulcherrima 147, M. pulcherrima 149, M. sinensis 1144, and M. zizyphicola 1147. The produced biomasses were analyzed using gas chromatography; in analyses, individual fatty acid composition was determined. Visible changes could be observed at different cultivation temperatures and used substrates. The best results were achieved by substrates that contained Metschnikowia sinensis 1144, while all selected yeasts were capable of lipid production. The highest representation of polyunsaturated fatty acids was demonstrated in each analyzed yeast.

National Repository of Grey Literature : 118 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.