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Mikroplasty v mořských plodech a jejich dopad na lidské zdraví
Formanová, Michaela
This bachelor thesis summarizes current knowledge regarding the accumulation of microplastic particles in the marine fauna and their impact on marine organisms. The uptake of microplastics has been demonstrated in laboratory and natural conditions in various marine organisms, including zooplankton, oysters, mussels, and shrimp. Microplastic particles are transferred from lower to higher taxonomic levels through the food chain via trophic transfer. The model transport within the food web was studied in a marine crab that was fed with mussels contaminated with microplastics. Microplastic fragments were able to penetrate from the crab's gastrointestinal tract into surrounding tissues. Microplastics are receiving a lot of attention in research as potential carriers of dangerous chemicals. The consequences of microplastic contamination on the food chain and human health are not sufficiently explored and require further study.
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Determination of arsenic species in seafood reference materials by ICP-MS with hydride generation and cryotrapping
Pokorná, Nikola ; Matoušek, Tomáš (advisor) ; Červený, Václav (referee)
The aim of this work was to determine chemical species of arsenic in sea originating certified reference materials. Measurements were done using method of hydride generation. Hydrides were preconcentrated in liquid nitrogen cooled tube and detected using inductively coupled plasma mass spectrometry. During the testing of the method, mutual conversion of arsenic species was observed for inorganic arsenic, monomethyl arsenic and dimethylarsenic. Further study revealed that with presence of matrix and hydrogen peroxide, demethylation occured only in hydride generation phase, not during extraction. Dissociation of hydrogen peroxide in extracts was verified using catalase. End of the demethylation process was proved using measurement with addition of arsenic species standards. The newly invented procedure was used to determine arsenic species in reference materials with sufficient accuracy. Final results are compatible with results from different method, and already published results as well. Key words: speciation analysis, arsenic, hydride generation, seafood, inductively coupled plasma mass spectrometry
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Products from aquaculture: Market, quality and new product development
NEBESKÝ, Václav
Fish are one of the main food sources throughout the planet and, in some parts of the world, especially in developing countries they are the only source of animal protein of local residents. Since the beginning of human civilization, fish have been caught in fresh and salt waters. Despite the fact that global fish consumption has been constantly increasing and it currently accounts for almost 20 kg of fish per person per year, the situation in the Czech Republic has been changing only slowly. The Czech Republic is known for traditional fish production in pond aquaculture with long historical roots and is currently ranked 6th within the European Union. However, fish consumption is generally one of the lowest in Europe. The annual consumption is only 5.5 kg of fish per person per year, of which fish from domestic aquaculture amount to only 1-1.5 kg. Despite the fact that fish consumption in the Czech Republic has been low in the long run, the interest of consumers has been shifting to more expensive and better quality food. They are commodities such as Atlantic salmon, tuna and crustaceans which lack typical characteristics of products from the Czech aquaculture, i.e. the characteristic taste, aroma and presence of muscle bones. These changes in consumer´s behaviour were recorded on the basis of a study focusing on the import of fishery and aquaculture products into the Czech Republic. One of the goals of this doctoral thesis were the applied results in the form of newly developed products using fish meat, less valuable parts of fish (tailpiece) and wastes from fish processing (skin, head). Due to the nature of these applied results, their registration was done in the form of utility models with the Industrial Property Office of the Czech Republic. One of the newly developed and successfully offered products on the market is carp pâté. It is made of machine-separated carp meat and contains 90% of the meat in the product. In addition to the basic pâté, there are currently other four variants (with pepper, smoked fish, almonds and cranberries). From the above, it is clear that there are many possibilities and opportunities how to increase the consumption and use of fish from domestic aquaculture. When introducing new products from fish, which are bred in ponds, the marketing must also be used to promote their indisputable benefits. And this is mainly the fact that it is a healthy and quality domestic raw material from the Czech agriculture. The very high quality and minimal occurrence of foreign substances in products from the Czech aquaculture were confirmed by our study. In the framework of this thesis, the screening of various fishery and aquaculture products, commercially available within the Czech Republic, was carried out with regard to the occurrence of heavy metals. The results of this study showed a very good quality of these products with a low content of heavy metals. Measured values of these elements in products from the Czech aquaculture were well below the allowed limit and their consumption does not pose any health risks. Due to the nature of the obtained data, it is possible to process and publish this study in a popular-scientific form to the general public. The right form of communication and contact with the public will be a key factor in the future in introducing new aquaculture products and increasing fish consumption in the Czech Republic.
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Speciation analysis of inorganic arsenic in seafood material
Pokorná, Nikola ; Matoušek, Tomáš (advisor) ; Musil, Stanislav (referee)
This thesis was focused on extraction of individual arsenic species from reference materials of fish protein DORM-3 and DORM-4. Extracts were then analyzed by a hydride generation method with detection by inductively coupled plasma mass spectrometry. Materials were extracted in two ways - in a microwave device and in a heating block. It was found that extraction with 2% nitric acid is not efficient. Extraction performed in 2% nitric acid with addition of hydrogen peroxide at various concentrations increased the extraction yield, but it caused conversion of arsenic species. This conversion would mean the overestimation of inorganic arsenic content.
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The Analysis of Fish and Seafood Market in Czech Republic
Šáchová, Lucie ; Mlejnková, Lena (advisor) ; Čáp, Petr (referee)
Diploma thesis describes the composition of fish meat and its inventions in the diet, shows the development of global fish consumption and the development of fish consumption in the country. Examines the current product portfolio and provides an overview of entities operating in the CR market. Based on the questionnaire provides a forecast likely future trends and anticipated developments.
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