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Characterization of lipids in cheese analogues
Bittnerová, Eva ; Šimíčková, Adéla (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the identification and quantification of free and bound fatty acids in samples of vegetable oils, specifically in linseed and rapeseed, and in cheese analogues made from them. The theoretical part deals with the characterization of cheese analogues, the composition and technology of fresh cheese production and the description of selected vegetable oils. It also contains the principle and instrumentation of gas chromatography with a flame ionization detector. In the experimental part, model samples of fresh cheese analogues with the addition of linseed and rapeseed oil and the corresponding oil as the basic raw material for their production were analyzed. The fat was extracted from the cheese analogues with a mixture of diethylether and petroleumether, the fatty acids were converted to methylesters by acid esterification with methanolic bortrifluoride catalyst and determined by gas chromatography with flame ionization detection. A total of 15 fatty acids were identified, predominantly oleic, linolenic and palmitic acids. In both oils, oleic, linoleic and linolenic acids were the most represented; significant amounts of myristic, palmitic and stearic acids were also found in the analog samples. The content of free fatty acids was significantly lower than that bound of all samples.
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Volatile profile of unusual type of fruit (Asimina triloba)
Pallová, Jana ; Šimíčková, Adéla (referee) ; Vítová, Eva (advisor)
The purpose of this bachelor thesis is to determine aroma active substances in an unusual fruit - pawpaw (Asimina triloba). The theoretical part consists of a general description of the plant and characterization of its characteristics, composition and use. Furthermore, the issue of aroma active substances are processed as well as the method of their determination by solid-phase microextraction in connection with gas chromatography and mass spectrometry. The experimental part deals with the identification and quantification of aroma active substances using the selected method HS-SPME-GC-MS in three varieties - PA-Golden, Rebecca's Gold and NC-1. Differences in the number and content of volatile substances were found among the varieties. The lowest values were PA-Golden. In total, 105 compounds have been identified, including 7 aldehydes, 15 alcohols, 58 esters, 6 ketones, 4 lactones, 1 nitrogen compound, 1 alkane, 4 acids, 2 phenols, 1 alkenes, 4 terpenoids, and 2 other compounds.
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Impact of elevated carbon dioxide concentration on protein content of gliadin fraction in winter wheat
Šimíčková, Adéla ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
The aim of this bachelor thesis was to study the impact of elevated CO2 concentration, nitrogen fertilization and UV radiation on the content of gliadin fractions in winter wheat. Winter wheat (Triticum aestivum) var. Bohemia was cultivated in conditions with ambient and elevated (700 mol mol-1) CO2 concentrations. Nitrogen nutrition (200 kg N ha-1) was added to half of the samples, while the another half of samples remained unfertilized. Plants were grown in greenhouses both with shielded UV-B radiation and with normal UV radiation. Environment with natural rainfall was the same for all of these variants. Gliadins were extracted by 2-chlorethanol, separated by A-PAGE method and subsequently quantified by computer densitometry. Significant increase of gliadin proteins was noticed in conditions of nitrogen fertilization in natural UV radiation, both in elevated and ambient CO2 concentrations, whereas in an eliminated UV-B radiation significant effect of nitrogen was not observed. Therefore UV radiation influenced in combination with nitrogenous nutrition as stimulative factor. However, statistically significant impact of evelated CO2 concentration on gliadin content was not proved.
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Confirmation of identification of volatile substances by calculation of retention indexes
Cviková, Sára ; Šimíčková, Adéla (referee) ; Vítová, Eva (advisor)
This bachelor thesis is focused on verifying the identification of volatile compounds using retention indices. The HS-SPME-GC-MS was used for determination. First part is theoretical and is focused especially on the brief definition of terms such as gas chromatography, retention time, retention index, mass spectrometry, however, the chemical and physical description of the CBD oil sample, which was used to prove the function of retention indices, is also mentioned. The standard homologous set of n-alkanes (C8 - C20) was used to determinate the retention indices, which was analyzed under the same conditions as the sample of CBD oil. In the CBD oil 38 volatile compounds were successfully identified. Their identification was confirmed by calculating their retention indices using the equation by H. van der Dool and D.J. Kratz, and comparing with tabulated values for the same type of chromatographic column.
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Influence of the filtration and pasterurization on content of selected vitamins in beer
Šimíčková, Adéla ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This master thesis focuses on the influence of the filtration and the pasteurization on the content of the selected vitamins in beer. Specifically, the vitamin B2, B3, B6, B9 and B12. The high performance liquid chromatography with diode array detector was used as a separation method for the vitamin content analysis. First this method was optimized and then validated. The data obtained by analyzing 28 beer samples were evaluated using a statistical method – the analysis of variance. This method provided parameters P, F and Fcrit which are important for the assessment of the statistically significant differences between the individual groups of beer . Based on these parameters, a significant effect of the filtration was observed for the vitamin B2 and B3. The filtration has reduced the amount of the vitamin B2 while it increased the concentration of the vitamin B3. The pasteurization had no significant effect on the vitamin content.
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Characterization of lipids in cheese analogues
Bittnerová, Eva ; Šimíčková, Adéla (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the identification and quantification of free and bound fatty acids in samples of vegetable oils, specifically in linseed and rapeseed, and in cheese analogues made from them. The theoretical part deals with the characterization of cheese analogues, the composition and technology of fresh cheese production and the description of selected vegetable oils. It also contains the principle and instrumentation of gas chromatography with a flame ionization detector. In the experimental part, model samples of fresh cheese analogues with the addition of linseed and rapeseed oil and the corresponding oil as the basic raw material for their production were analyzed. The fat was extracted from the cheese analogues with a mixture of diethylether and petroleumether, the fatty acids were converted to methylesters by acid esterification with methanolic bortrifluoride catalyst and determined by gas chromatography with flame ionization detection. A total of 15 fatty acids were identified, predominantly oleic, linolenic and palmitic acids. In both oils, oleic, linoleic and linolenic acids were the most represented; significant amounts of myristic, palmitic and stearic acids were also found in the analog samples. The content of free fatty acids was significantly lower than that bound of all samples.
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Confirmation of identification of volatile substances by calculation of retention indexes
Cviková, Sára ; Šimíčková, Adéla (referee) ; Vítová, Eva (advisor)
This bachelor thesis is focused on verifying the identification of volatile compounds using retention indices. The HS-SPME-GC-MS was used for determination. First part is theoretical and is focused especially on the brief definition of terms such as gas chromatography, retention time, retention index, mass spectrometry, however, the chemical and physical description of the CBD oil sample, which was used to prove the function of retention indices, is also mentioned. The standard homologous set of n-alkanes (C8 - C20) was used to determinate the retention indices, which was analyzed under the same conditions as the sample of CBD oil. In the CBD oil 38 volatile compounds were successfully identified. Their identification was confirmed by calculating their retention indices using the equation by H. van der Dool and D.J. Kratz, and comparing with tabulated values for the same type of chromatographic column.
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Volatile profile of unusual type of fruit (Asimina triloba)
Pallová, Jana ; Šimíčková, Adéla (referee) ; Vítová, Eva (advisor)
The purpose of this bachelor thesis is to determine aroma active substances in an unusual fruit - pawpaw (Asimina triloba). The theoretical part consists of a general description of the plant and characterization of its characteristics, composition and use. Furthermore, the issue of aroma active substances are processed as well as the method of their determination by solid-phase microextraction in connection with gas chromatography and mass spectrometry. The experimental part deals with the identification and quantification of aroma active substances using the selected method HS-SPME-GC-MS in three varieties - PA-Golden, Rebecca's Gold and NC-1. Differences in the number and content of volatile substances were found among the varieties. The lowest values were PA-Golden. In total, 105 compounds have been identified, including 7 aldehydes, 15 alcohols, 58 esters, 6 ketones, 4 lactones, 1 nitrogen compound, 1 alkane, 4 acids, 2 phenols, 1 alkenes, 4 terpenoids, and 2 other compounds.
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Influence of the filtration and pasterurization on content of selected vitamins in beer
Šimíčková, Adéla ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This master thesis focuses on the influence of the filtration and the pasteurization on the content of the selected vitamins in beer. Specifically, the vitamin B2, B3, B6, B9 and B12. The high performance liquid chromatography with diode array detector was used as a separation method for the vitamin content analysis. First this method was optimized and then validated. The data obtained by analyzing 28 beer samples were evaluated using a statistical method – the analysis of variance. This method provided parameters P, F and Fcrit which are important for the assessment of the statistically significant differences between the individual groups of beer . Based on these parameters, a significant effect of the filtration was observed for the vitamin B2 and B3. The filtration has reduced the amount of the vitamin B2 while it increased the concentration of the vitamin B3. The pasteurization had no significant effect on the vitamin content.
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Impact of elevated carbon dioxide concentration on protein content of gliadin fraction in winter wheat
Šimíčková, Adéla ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
The aim of this bachelor thesis was to study the impact of elevated CO2 concentration, nitrogen fertilization and UV radiation on the content of gliadin fractions in winter wheat. Winter wheat (Triticum aestivum) var. Bohemia was cultivated in conditions with ambient and elevated (700 mol mol-1) CO2 concentrations. Nitrogen nutrition (200 kg N ha-1) was added to half of the samples, while the another half of samples remained unfertilized. Plants were grown in greenhouses both with shielded UV-B radiation and with normal UV radiation. Environment with natural rainfall was the same for all of these variants. Gliadins were extracted by 2-chlorethanol, separated by A-PAGE method and subsequently quantified by computer densitometry. Significant increase of gliadin proteins was noticed in conditions of nitrogen fertilization in natural UV radiation, both in elevated and ambient CO2 concentrations, whereas in an eliminated UV-B radiation significant effect of nitrogen was not observed. Therefore UV radiation influenced in combination with nitrogenous nutrition as stimulative factor. However, statistically significant impact of evelated CO2 concentration on gliadin content was not proved.
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