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The assesment of chloramphenicol residues in biological material, water and feed by GC/MS
Lukačková, Dagmar ; Šalplachta, Jan (referee) ; Rejtharová, Martina (advisor)
This diploma thesis addresses the presence and determination of chloramphenicol residues in biological materials. The theoretical part presents the literature retrieval containing information about veterinary medicaments with the banned use in food producing animals and also the sum of the legislative requirements concerning the presence of these substances in foodproducts and raw food materials of animal origin. The comparison was carried out between the existing analytical methods used for the determination of chloramphenicol residues in different biological materials, which are altogether based on the solid phase extraction for the extract cleaning and the new procedures for sample preparations using columns where the sorbent performs on the molecularly imprinted polymers principle.
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Residential complex Brno Holasky, V Aleji locality
Mokrá, Petra ; Kopáčik, Gabriel (referee) ; Sátora, Josef (advisor)
The area is located in the city of Brno - Tuřany. It is defined from the west Černovice river with natural monument Holásky Lake, from east by railway line from the south street U Potoka. The aim is a comprehensive urban design of the development area. The existing area is a typical structure of the former village connected to Brno. Location is convenient for the development of residential functions and optional equipment. The main objective of the solution is to design urban areas, which would carry on the original structure of the village and effective form of use of the available unused area.
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Volatile profile of Edam type cheese
Balej, Marek ; Kovalčík, Adriána (referee) ; Vítová, Eva (advisor)
This bachelor thesis is focused on specification volatile profile of eidam cheese types, which are natural semi hard cheeses with low heat curd. Subject of theoretical part is basic differentiation of cheeses, description of chemical composition and characteristic of eidam cheese types. After that, issue of their manufacturing process is processed and aroma active substances are described. In the last part of this section, the attention is focussed on specification method of solid phase microextraction connected with gas chromatography with mass spectrometry detection. Experimental part deals with HS-SPME-GC-MS method application on identification of volatile compounds in eidam cheese types. Samples of model cheese were manufactured at Tomas Bata University in Zlín with the use of various added microbial starter cultures and eidam type cheeses with various fat content bought on the market. A total of 64 compounds were identified in samples; of those 18 alcohols, 11 esters, 9 ketones, 7 aldehydes, 5 acids, 3 lactones, 2 terpene hydrocarbons, 2 terpene alcohols, 1 terpene ketone, 1 terpene aldehyde, 4 sulphurous compounds and 1 phenol. The differences were found among model cheese samples and market bought samples in the case of number and type of volatiles.
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Modern detection methods of energetic materials
Šesták, Jozef ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
The review of modern detection methods of explosives was composed. Firstly the thesis deals with the detection methods commonly used in forensics science such as gas chromatography, mass spectrometry, ion mobility spectrometry, Raman spectroscopy and mainly their innovations. Then the thesis is focused on simple but very sensitive methods using fluorescence and chemiluminescence. At the end a methods as the results of a latest research are mentioned. The main of them are micro cantilever sensors and differential reflectometry. Security and counterterrorist warfare is main point of thesis.
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Aroma profile of processed cheese analogues
Kučerka, Štefan ; Saláková,, Alena (referee) ; Vítová, Eva (advisor)
The aim of this bachelor thesis was to identify and semiquantify volatile (aroma) compounds in samples of processed cheese analogues, produced with full or partial substitution of milk fat with selected vegetable fats/oils (coconut, palm, blended, grapeseed, linseed, apricot kernel, blackcurrant seed). Theoretical part is dealing with characterization of processed cheese analogues, procedure and ingredients used in production. This is followed by a topic of aroma compounds. At the end of theoretical part the method of solid-phase microextraction, gas chromatography and mass spectromectry is described. In the experimental part the model samples of processed cheese analogues were analyzed. They were produced in Tomas Bata University in Zlin. Edam cheese and mentioned fat were used as ingredients. HS-SPME-GS-MS method was chosen to isolate and determinate volatile (aroma) compounds in samples. A total of 152 volatile compounds were identified in samples. Differences in the number and content of the identified compounds were found among samples, aldehydes and acids belonged to the most important groups, sample content speaking.
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Detection methods of energetic materials
Procházka, Michal ; Diviš, Pavel (referee) ; Friedl, Zdeněk (advisor)
A research on current methods of detection of explosives and related materials was made. At first the thesis studies methods of detection and analysis of explosives including chromatographic methods (TLC, GC, HPLC, IC), mass spectrometry and its variations, ion mobility spectrometry and infra-red spectroscopy. Next the attention is placed on detection of explosives in solid phase by X-ray detection, nuclear magnetic and quadrupole resonance and thermal neutron activation. Practical applications of these methods are of great importance in this thesis as well as their usage in the counterterrorist fight.
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Assessment of aroma active compounds in selected type of cheese
Páral, Marek ; Mahdalová, Martina (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the determination of aroma active compounds in white mold cheeses, i.e. soft, mold cheeses maturing from the surface. In the theoretical part, cheeses are generally characterized, their chemical composition, properties and process of production are described. After that It´s focused on aroma active compounds. The metabolism of their formation in cheese and their determination by means of solid phase microextraction and gas chromatography with mass detection are described. In the experimental part of the bachelor thesis, the SPME-GC-MS method was used for identification and semiquantitative determination of aroma active compounds in three samples of white mold cheeses made in the Czech Republic purchased in a market. Comparison of cheeses showed differences in the number and types of determined compounds as well as in total contents. A total of 66 volatile compounds were identified in samples; of those 1 aldehyde, 17 alcohols, 19 esters, 9 carboxylic acids, 15 ketones, 1 sulphur compound ¨ and 3 hydrocarbons.
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The determination of mycotoxins in commercial beers
Martiník, Jan ; Benešová,, Karolína (referee) ; Mgr. Marek Pernica, Ph.D (advisor)
Mycotoxins are secondary metabolites of microscopic fibrous micromycetes that are able to infect cereals. The use of contaminated materials can lead to transfer of mycotoxins into the final product, such as beer. The master’s thesis deals with the determination of mycotoxins in beers. The theoretical part of this thesis describes selected mycotoxins, their occurrence, toxic properties and legislative limits of the European Union. The theoretical part also deals with the description of beer production and the possibilities of mycotoxin determination. The theoretical part also describes the statistical methods used for data processing. The experimental part of this work describes the validation of the method for determination of mycotoxins in beers. This section also describes the optimization of mycotoxin extraction using a commercially available 11+Myco MS-PREP® immunoaffinity column. The conditions for the determination of mycotoxins on UPLC-MS/MS are given in this thesis. The validation parameters such as linearity, accuracy, precision, LOD and LOQ were determined. This section contains a description of beer samples used for the determination of mycotoxins. The goal of the thesis was to optimize and validate the method for determination of mycotoxins in beers. From the validation parameters, it was found that this method is suitable for its intended purpose, namely for mycotoxins aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, fumonisin B1, fumonisin B2, fumonisin B3, ochratoxin A, ochratoxin B, zearalenone, -zearalenol, -zearalenol, -zearalanol, -zearalanol, deoxynivalenol, 3-acetyldeoxynivalenol, T-2 toxin and HT-2 toxin. The recoveries of this method ranged from 72,2 % to 100,0 %. The validated method was used for determination of above-mentioned mycotoxins in 89 beers. Of the total number of beers, 37 were produced in the Czech Republic and 52 in other European countries. Mycotoxins deoxynivalenol, T-2 toxin and HT-2 toxin were found in all beer samples. Common mycotoxins included fumonisin B1, ochratoxin A, -zearalenol and 3-acetyldeoxynivalenol. The mycotoxins aflatoxin B1, aflatoxin B2, aflatoxin G1, fumonisin B2, fumonisin B3, zearalenone and ochratoxin B were identified in less than 50 % of the samples. Mycotoxins aflatoxin G2, -zearalenol, -zearalanol and -zearalanol were not determined in any tested samples. The results of the analysis were subjected to statistical processing where the concentrations determined in Czech and European beers were compared. Principal component analysis and correlation analysis were created for aflatoxin B1, fumonisins, ochratoxin A, -zearalenol, deoxynivalenol, 3-acetlydeoxynivalenol, T-2 toxin and HT-2 toxin. The results of the analysis were compared with published studies.
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Changes of sensory active substances during ripening of selected type of natural cheese
Sýkora, Michal ; Buňková, Leona (referee) ; Gregor,, Tomáš (referee) ; Buňka, František (advisor)
The presented dissertation is a study focused on the characterization of sensory quality, especially the flavour of model samples of natural cheeses. Attention is aimed to the composition and content of volatile (sensory active) substances as important markers of flavour and free/bound fatty acids as their precursors. The headspace solid phase microextraction in conjunction with gas chromatography with mass spectrometry was used to determine volatiles. For the determination of fatty acids, the lipids were isolated from the sample with a solvent mixture of diethyl ether and petroleum ether, followed by esterification using a methanolic solution of boron trifluoride as a catalyst and final analysis by gas chromatography with flame ionization detection. The experimental part was divided into two experiments; in experiment I, Moravský bochník type cheeses (45 % fat in dry matter., 60 % dry matter) were analysed, in experiment II, Edam type cheeses (45 % fat in dry matter, 50 % dry matter). Model samples of cheeses were made at Tomas Bata University in Zlín. For all samples, a classical mesophilic culture containing Lactococcus spp. and Leuconostoc spp. was used, this was always supplemented with a suitable monoculture of thermophilic bacteria; in the case of Moravský bochník cultures of Streptococcus thermophilus and Lactobacillus helveticus and in the case of Edam cheeses Lactobacillus casei and Lactobacillus plantarum. The essence of both experiments was to assess the influence of the used microbial cultures on the above-mentioned parameters, at the same time their changes during the ripening of the cheeses were monitored. The results showed that the addition of thermophilic cultures, as well as the maturation process did not affect the number of fatty acids or volatiles, but significant differences were found in their content. The content of bound fatty acids decreased during cheese ripening due to ongoing lipolytic changes while increasing the content of free fatty acids and their subsequent degradation to volatile substances, which ultimately contribute to the taste and aroma of the cheese. Ketones and acids were the most quantitatively present in all samples. During maturation, contrary to expectations, the content of identified volatiles also decreased. The addition of the thermophilic cultures didn’t have a clear effect and varied depending on the maturation phase. In the first phase, although they showed more pronounced lipolytic activity, the subsequent metabolic processes - the breakdown of free fatty acids into volatile substances, compensated for these differences. These results confirm a significant share of the basic mesophilic culture in the formation of volatile substances, in particular the flavour of cheeses.
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Comparison of aroma active compounds of selected types of cheese
Brožová, Michaela ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the determination of aroma active substances in selected white mold cheeses, which are/are not awarded with the „Protected Designation of the European Union“ and their mutual comparison. In the theoretical part cheeses are characterised , including general production technology. The white mold cheeses are then described in detail. This is followed by the literary search dealing with the problematic of aroma active substances in cheeses. In conclusion of the theoretical part the method of their determination using solid phase microextraction and gas chromatography with mass detection is described. The SPME-GC- MS method was chosen for the experimental part of the determination of aroma active substances in selected white mold cheeses. A total of 12 cheeses were analyzed, of which 6 were Czech and Slovak and 6 were French with a protected designation of origin. The differences between individual samples were found in the number and type of the identified volatile compounds. A total of 78 volatiles were identified in selected cheeses, of which 20 were alcohols, 19 esters, 12 ketones, 11 acids, 4 sulfur compounds, 3 hydrocarbons, 3 lactones, 2 aldehydes, 2 phenols, 1 nitrogen compound. The cheeses were compared in terms of the identified compounds, and finally the results were statistically evaluated by the PCA method.
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