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The quality of eggs - general, functional and nutritional properties
PECH, Miloslav
This bachelor's thesis, processed in the form of a literary review, focuses on a comprehensive view of hen's eggs, analyzing their general, functional, and nutritional properties. After the introduction, a literary review follows, mapping the biological origin and domestication of the chicken, and then summarizing the current state of chicken farming. The thesis then delves into the formation and development of eggs, examining the structure and chemical composition of the yolk and albumen, including their proteins, lipids, carbohydrates, pigments, vitamins, and minerals. The physicochemical properties of eggs are also analyzed, including a total of seven properties such as specific gravity, freezing point, or refractive index. A detailed examination of the functional properties of eggs follows, which represent a key element in understanding their wide use in the food and culinary industries. The thesis focuses on analyzing the mechanisms through which hen's eggs can form gels, foams, and emulsions, which are properties that play an important role in various food processes and recipes. These properties are essential for the production of various foods, such as gelatin desserts, leavened doughs in baking, sauces, and mayonnaises. Eggs are also recognized as functional food because they are a rich source of nutrients, including vitamins, minerals, and biologically active substances that can contribute to overall health. These substances can, for example, help reduce the risk of heart disease and improve eye health. In the next section, the thesis focuses on the nutritional properties of eggs, examining microbial contamination, egg allergies, and biologically active substances such as choline, immunoglobulin Y (IgY), and lutein and their impact on human health. An overview of this section provides a deeper understanding of hen's eggs and their influence on human nutrition and health.
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The effect of cream and curd proportion on milk desserts' composition, technological and sensory properties
JANŮ, Tereza
The aim of the Master's thesis was to evaluate 1) the effect of the proportion of cream and curd and 2) the effect of the flaxseed meal (FM) addition on the chemical composition and technological and sensory properties of milk desserts. The literary part focuses on milk desserts, their enrichment and the importance of flax (Linum usitatissimum L.). The experimental part deals with the sensory evaluation of made milk desserts and the analysis of selected indicators of made milk desserts.
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Influence of fluxes on weld metal properties
Holub, Kamil ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
This thesis deals with the topic of submerged arc welding – an electric arc method of fusion welding, that uses a layer of granulated flux to shield the weld pool from atmospheric gases. Theoretical part is devoted to the description of the welding method and fluxes currently used. The practical part contains an experiment, which consists of making two weld deposits on structural steel S235JR by using different fluxes. First weld deposit is made with OK 10.62 Flux. The same flux alloyed with the Tribaloy T-800 laser cladding powder is used for the second weld deposit. Test specimens are examined on the basis of influence of fluxes combined with a single electrode wire.
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Chemical composition of berries juices from some cultivars of European elder
Šafránková, Petra ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
This thesis deals with chemical composition of the juice from selected species of elderberry (Sambucus nigra L.). The theoretical part is dedicated to botanical characteristic of elderberry including the origin and the extension. There are also mentioned the medical effects of elderberry with the description of the cultivation of this herb with the examples of particular cultivated species. In the experimental section were laid down the particular chemical parameters (yield, pH, relative density, titrable acidity, formol number, content of instant dry mass and reducing sugar) in the juice from the fruits of these cultivated species of elderberry: Albida, Allesö, Aurea, Bohatka, Dana, Heidegg 13, Haschberg, Körsör, Mammut, Pregarten, Riese aus Voßloch, Sambo, Sambu, Samdal, Sampo, Samyl a Weihenstephan. The median of the yield has been 700,0 ml/kg, the median for the pH assessment has been 4,03. The median of relative density of all species was 1,0361, the median of titrable acidity was 141,83 mmol l -1. The median of the overall content of amino acids was 30,5 ml 0,1 mol l-1 NaOH/100ml, the median of the content of the dry mass was 9,5 weight %. The median of the assessment of the reducing sugar was 5,02%.
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The basic chemical parameters of berries from some black currant cultivars
Sailová, Genar ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
This thesis deals with the chemical analysis of the juice from fruits of cultivated varieties of blackcurrant (Ribes nigrum L.) The theoretical part is dedicated to botanical characteristic of black currant including the origin and the extension. There are also mentioned the history of cultivation currant and breeding of the varieties of black currant. Chemical composition of currant is also described in this part. In the experimental part some basic chemical parameters (yield of juice, soluble dry matter content, dry matter general content, pH, titratable acidity, formol number and reducing saccharides content) of four black currant cultivars were determined.
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Study of the effect of metallurgical and technological parameters on mechanical properties of aluminium alloys
Pešek, Jakub ; Krahula, Karel (referee) ; Zemčík, Ladislav (advisor)
Sugested thesis has been made with the intent to observe and describe the length of the modifying effect of three different types of modifiers and their effect on the mechanical properties of aluminium alloy. Next step was to process and evaluate links between mechanical properties and chemical composition. Chemical analysis and mechanical properties of cast samples were obtained. For this purpose and a method of metallographic processing was applied afterwards. The grain size was evaluated before and after the heat treatment. Measurements of the secondary dendrite branches and evaluation of the eutectic morphology were made. The hardness was measured on selected samples.
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Chemical and sensory analysis of fruit juice from selected cultivars of European elder
Ješková, Kristýna ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
The aim of this thesis is the chemical and sensory analysis of the juice from fruits of cultivated varieties of elderberry (Sambucus nigra L.). In the theoretical part botanical description of elderberry including its distribution and places of existence are given. There are also mentioned medical effects and collection of various parts of the elderberry as well as breeding certain species and methods evaluating sensory features of the juice samples prepared from the cultivated varieties of elderberry. In the experimental part some chemical parameters (yield, soluble dry matter content, relative density, pH, titratable acidity, formol number, reducing saccharides) in the juice of berries of eighteen cultivated varieties of elderberry were determined. In fifteen cultivated varieties was made sensory evaluation using profile test and scale. The aim of the evaluators in the evaluation using scale was to evaluate the taste, smell, sensory quality and preferences according to seven point cathegorical hedonic scale. In the profile test, five point scale was used to evaluate the intensity of chosen flavours: acidic, sweet, bitter and others. Overall impression of the sensory evaluation was rather not positive. In majority of the samples the taste and smell were evaluated as good or satisfactory and their general acceptability, too. The juice from the wild elderberry was estimated as worse than in other samples, its taste, smell and overall acceptability were unsatisfactory. In majority of the cultivated varieties were the taste and smell estimated as unsatisfactory as well as their general acceptability.
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