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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Posouzení vlivu pasterizace a filtrace na obsah vybraných chemických složek piva / Evaluation of the influence of the pasterization and filtration on selected chemical components of beer

Vopelková, Dominika January 2017 (has links)
The aim of this work was to study the influence of the pasteurization and filtration on selected chemical compounds in beer. Specifically, the influence on elemental composition, content of organic acids, carbohydrates and phenolic substances was studied. Optical emission spectrometry with inductively coupled plasma (ICP-OES) was used for elemental analysis of beer. Analysis of organic acids was evaluated by Ion chromatography. For analysis of carbohydrates was used High performance liquid chromatography with ELSD detector (HPLC-ELSD), phenolic compounds was evaluated by HPLC with diode array detector (HPLC-DAD). Data from analysis of beer was performed by usage of statistical methods (analysis of variance and principal component analysis). Parameters that showed the most significant differences between individual groups of beers were obtained. Correlations between the variables and the technological beer processing operations were found. 12 parameters of total 23 were affected. The effect of filtration and pasteurization was observed in content of the iron, silicon, potassium and magnesium, malate, monosaccharides glucose and fructose and phenolic compounds.
32

Fyziologický základ tolerance rostlin rodu Fragaria k abiotickým stresům. / The physiological basis of abiotic stress tolerance in Fragaria genus plants.

Hamet, Jaromír January 2016 (has links)
Abiotic stresses - drought, salinity or extreme temperatures - cause morphological and physiological changes, affect growth, development and plant productivity. In crops, these limitations often reduce yields up to 50%. Plants have developed various mechanisms ensuring some degree of abiotic stress tolerance, which undoubtedly include changes in carbohydrate metabolism. The nature of many defense mechanisms is not yet fully understood, moreover, most findings were obtained by studying model plants and little is known about their validity in crops. This work was therefore focused on woodland strawberry (Fragaria vesca L.) from economically important family Rosaceae. Controlled conditions and targeted exposure to stress factors was obtained through the cultivation in vitro. Strawberry plants and callus cultures were exposed to various stresses and their combinations, better reflecting the natural conditions. At various stages of stress reaction, growth characteristics, changes in the content and the spectrum of soluble carbohydrates and oxidative stress levels were monitored and compared with plants growing under optimal conditions. Abiotic stress responses of strawberry plants were very inhomogeneous, which complicated the obtaining of statistically significant results. The only significant response...
33

Analýza učebnic a tvorba učebních textů s tematickým celkem sacharidy a jejich metabolismus pro školy gymnaziálního typu / The analysis of the textbooks and the creating of the learning texts about the thematic unit of carbohydrates and their metabolism for the gymnasial grammar schools

Šmídl, Milan January 2013 (has links)
1 Abstract: The main parameters describing content and the accessibility of information from textbooks are many aspects such as text difficulty and others. Individual characteristics of pupils - that are represented by chosen student preconceptions and misconceptions - also belong to key factors. The providing of the comprehensive view of the issues regarding analysis and the linking of acquired pieces of knowledge with the practical textbook creation have been the main aims of this dissertation. The creation of an instructional text follows the analysis results of the topic carbohydrates and their metabolism in chosen textbooks and the preconception analysis of biochemical terms. The instructional text respects the results of the analysis. The theoretical background of textbook creation (the functions of textbooks, their structure, content, characteristics and investigated parameters) has been described in detail in the theoretical part of this doctoral thesis. It is followed by the survey of the information concerning student preconceptions and the possibilities for their analysis and use in teaching. The aspects of textbooks use from the perspective of pupils, teachers and publishers, as well as the relation of the topic carbohydrates and their metabolism to curriculum documents have been described in...
34

Kvalita lipidů našich hospodářsky významných druhů ryb / The lipid quality of our economically significant fish species

KREJSA, Jakub January 2015 (has links)
The level of fish consumption in the Czech Republic is very low. One of the possible factors influencing this situation is low awareness of the customer or consumer. The thesis "The Lipid Quality of our economically significant fish species" works with the list of nineteen economically most significant fish species not only including fish from the semi-intensive and intensive breeding, but also such species that are interesting for the consumption from the sport fishing point of view. The samples taken from particular fish were primarily used for the analysis of the fat content and fatty acid composition. The analysis established very interesting results in this field and created basis for further analysis for establishing atherogenic and thrombogenic index or for formation of nutritive values mentioned as "Big 7" (fat content and the ratio of fatty acid out of it, sacharide content and the sugar ratio in it, protein content, ash content and energy value) by particular fish species according to the regulation ES 1169/2011. The results of this work confirmed that the fat content and its composition are highly influenced by the type of ingested nourishment. The fish bred in semi-intensive way with the highest fat content are Common carp (7,62 ? 2,9 %) and Silver carp (6,87 ? 1,37 %). On the contrary the predatory fish evinced the fat content usually within 1%. The fish from extensive breeding or the types caught in sport fishing are in the fat con-tent more balanced. The fattest fish in this group is Silver Bream (5,52 ? 0,44 %) and the lowest content evinced Goldfish (1,14 ? 0,38 %). Also the species living in the aquaculture and living in the free waters as well were compared (Common carp, Rainbow trout, Peled, Tench, Wels catfish). The fatty acid composition significantly depends on the fat content. The predatory fish contain 195 - 219 mg×100 g-1, the most (p0,05) was found by the peled from the extensive breed (1048 mg×100 g-1 EPA + DHA). The participation of SFA by the most of the fish was under 30%, the content of MUFA was the highest by the Common carp (52,71 ? 7,75 %), the lowest by the European perch (18,83 ? 1,12 %). Pike, Zander and European perch contain relatively the most of PUFA, this is over 50%. All the fish species (Nile tilapia excluded) show in this study the values of atherogenic index below 0,5 and thrombogenic index below 0,4. The total energetic value was counted from the results of nutritional values presented in the "Big 7" list. The higher energetic value is directly proportional to the increasing fat content. The fish species included in this thesis show the total energetic value in the range of 500 - 900 kJ×100 g-1. The results of this study bring complete, laboratory proven information about the nutrition composition of our fish. This data can be appli-cable not only to increase the knowledge of the customers but mainly to be used by breeders and manufacturers of fish as an implement of fulfilling the duty of stating the nutrition facts on their products according to ES 1169/2011 on the providing infor-mation about the eatables to the consumers.
35

Dynamika akumulace nestrukturních sacharidů a aktivity enzymu Rubisco při zvýšené koncentraci oxidu uhličitého a manipulaci sinku u buku lesního / The dynamics of non-structural saccharides accumulation and Rubisco activity under the elevated carbon dioxide concentration and sink manipulation at beech

Uhrová, Lucie January 2012 (has links)
This diploma thesis deals with dynamic of accumulation of non-structural carbohydrates and activity of Rubisco enzyme at elevated concentration of CO2 on beech (Fagus sylvatica L.). Three years old seedlings of beech were cultivated in minisphere with ambient (385 µmol•mol-1, variant A), and with elevated concentration CO2 (700 µmol•mol-1, variant E) for four months. In every variant the first half of plants was fertilized by nitrogen (variant N+) and the second half was control (variant N-). Plants used for experiment were at first adapted for darkness for 12 hours. Subsequently tested leaves were cut off, leafstalk including short segment of branch (approximately 1 cm) was inserted into 0.7 M solution of sucrose (variant S) or water (variant V) and exposed to radiation 200 mol•m-2•s-1 for 0, 30, 60, 120, 180 minutes. Then leaf area and fresh mass of leaf blade were established, samples were fixed in liquid nitrogen and stored in deep freezer to analysis in –70 °C. Rubisco content was determined by SDS-PAGE method, Rubisco activity spectrofotometrically and content of non-structural carbohydrates by anthrone method and HPLC method. Rubisco content was significantly lower in the N- variant than in N+ variant. Rubisco content was also significantly lower in E than in A variant, which is an evidence of down-regulation. Rubisco activity is moderately stimulated at E variant with time, but differences between variant A and E are not statistically significant. Influence of sucrose feeding to Rubisco activity was not proved. Significant differences were detected by anthrone method in non-structural carbohydrates content between variants S and V, but not between variants A and E. Statistically significant increase of sucrose content with time was detected by HPLC method at variant AS, but not at variant ES.
36

Cereálie - aktivní složky, biologické účinky a vybrané aplikace v potravinářství / Cereals - Active Substances, Biological Effects and Selected Applications in Food Industry

Lichnová, Andrea January 2014 (has links)
The presented doctoral thesis is focused on the study of the biological effects of active compounds found in cereals, on the development of methods of analysis these effects, on the determination of the content of active substances and characterization of the relationship between composition and biological effects of cereals and cereal products. For the analysis several kinds of raw cereal samples (flakes, flour, germ, bran), flavored extruded cereal products and also samples of paddy and husked rice were chosen. To major types of analysed active compounds belong mainly phenolic compounds in the form of glycosides and aglycones, and also saccharides. Group parameters such as total polyphenols, flavonoids and total and reducing saccharides were determined spectrophotometrically, individual phenolics and saccharides were determined by high performance liquid chromatography (HPLC). TEAC, DPPH and CLAMS methods were used to determine the antioxidant activity. Indirect methods of determination of substances with antioxidant effect were used as well. Results of the total antioxidant activity were compared with values of antimutagenic/genotoxic activity obtained by several microbial test systems. Antimutagenic effect was expressed as a percentage of inhibition of effect of standard mutagen and could be considered as a potential preventive effect of cereals to DNA arising primarily by free radicals effect. The highest values of group and individual phenolics, antioxidant and antimutagenic activity were found in germs, bran, in buckwheat products and in coloured and raw rice. In flavoured cereal products addition of chocolate or fruit positively influences content of active phenolic substances as well as sugars, antixidant and antimutagenic activity. In a representative sample of Czech population, questionnairy study was performed to monitor interest in cereals and consumer preferences. The most of consumers consider cereals with chocolate flavour as less healthy than confirmed results of laboratory analyses. In this study some new food products were developed. Several types of model cereal products containing plant (fruit, vegetables) extracts were proposed. Extracts were added to cereals in freeze-dried and encapsulated form. The highest positive effect exhibited addition of local forrest fruit extract. Within preparation of encapsulated extracts several methods of preparing lipid or saccharides particles were also tested. The encapsulation efficiency of the methods and stability and size of particles were analysed. Optimal type of fortified cereal foods could be suggested based on the acquired results. Selected cereals were used as alternative carbon substrates (processed or raw) for the cultivation of microorganisms to produce enriched biomass usable in the feed industry. We can conclude that cereals in raw as well as processed form belong to universal foods and rich sources of biologically active substances. They can be processed by many ways. They can be used for direct consumption, as a part of new products and also undirectly as a substrate for feedstock.
37

Možnosti přípravy kombinovaných nápojů z vybraných druhů ovoce / Possibilities of preparation combined drinks from selected fruits

Zábranská, Miroslava January 2016 (has links)
This thesis deals with the preparation of the combined alcoholic beverages based on wine and fruit juices. The fruit juices were obtained from the selected fruits as honeysuckle, mulberry, dogwood, rose hips, elderberry, buckthorn and aronia. Some chemical properties e. g. total fenolics, total anthocyanins, vitamin C and sacharides were determined for characterization of the mentioned juices. As well as chemical parameter of juices, the same chemical parameters were determined on wine. There were prepared three sets of combined beverages from wine and juices. The two best evaluated beverages were chosen on the basis of their sensory evaluation. In the end, the same chemical properties were determined in both particular juices and resulting beverages.
38

Indukce tvorby hlíz u spontánně tuberizující linie bramboru: úloha sacharidů a mobilních transkriptů / Tuber induction in spontaneously tuberizing potato line: the role of saccharides and mobile transcripts

Stupecká, Lenka January 2018 (has links)
Potato is one of the most important agricultural crops and there is an attempt to increase and improve yields of tubers, among other things, by elucidation of the mechanisms that regulate the process of tuber induction. Potato tuberization is a morphogenetic process in which the tubers are formed from the underground parts of the stem - stolons. The correct timing of this process is controlled by a complex regulatory network and influenced by many internal and external factors. Under favourable conditions, an inductive signal is generated in the leaves and it is transported to the stolon by a "phloem information superhighway" driven by carbohydrates flow. The signal triggers cell division, expansion, and changes in the cell growth orientation in the stolon. The development of tubers is influenced by number of biochemical and morphological processes driven by a regulatory network of genes that are expressed in different parts of plants. This work was focused on Solanum tuberosum, Lada cultivar and its derived D69 mutant line with lacking isoform of manganese-stabilizing protein (MSP), which is so far the only dissimilarity identified under all tested conditions. I aimed to map the processes related to the production of carbohydrates in leaves (photosynthetic characteristics - rate of photosynthesis...
39

Role sacharidového metabolismu v obraně proti oxidativnímu stresu vyvolanému působením arsenu. / Role of carbohydrate metabolism in defence against oxidative stress induced by arsenic

Kofroňová, Monika January 2019 (has links)
Heavy metal contamination significantly reduces crop yields, causing serious problems in agriculture and having a major impact on human health if these contaminants enter the food chain. Understanding the mechanisms of plant responses could help to increase their resistance to heavy metals as well as their potential use in phytoremediation. Carbohydrates play an important role in plant growth and development as well as in defense reactions. This work summarizes the results of four publications focused on the effects of arsenic and thorium on antioxidant mechanisms in tobacco plants and horseradish root crops. Attention is paid, among other things, to the dynamics of sugar contents, which are potentially important molecules involved in the fight against oxidative stress. The first publication summarizes arsenic effects on plant physiological parameters, focusing on arsenic tolerance-enhancing mechanisms as well as summarizing the ability of plants to cope with arsenic-induced oxidative and nitrosative stress. Emphasis was placed on, among other things, a topic that was unjustly neglected in previous publications - i.e. carbohydrate metabolism. Further work was already experimental and dealt with the study of arsenic as a trigger of oxidative stress in the root culture of horseradish and...
40

Analýza sacharidů a markerů spalování dřeva v atmosférických aerosolech / Analysis of saccharides and markers of wood combustion in atmospheric aerosols

Kubátková, Nela January 2011 (has links)
Diploma thesis deals with the analysis of saccharides and markers of biomass and wood combustion in atmospheric aerosol, PM2,5. Theoretic part is focused on general characterisation of atmospheric aerosols and on the properties, sources and analysis methods of selected analysed organic compounds. The experimental part is focused on the optimization of method for simultaneous analysis of saccharides and tracers from biomass and wood combustion. Optimization of method includes selection of solvent for the extraction of compounds and optimization of derivatization process and GC/MS analysis. The optimized method was then applied for the analysis of selected compounds in real aerosol samples in the size fraction PM2.5. The concentrations of analysed compounds were compared in term of sampling seasons.

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