|
|
Basic chemical characteristics of chokeberry juices
Zámorská, Vendula ; Veselá, Mária (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals wirh characteristics of berries and assessment of basic chemical parameters of chokeberry juices (Aronia melanocarpa). The theoretical part is about the basic botanical description of selected varieties of Aronia and its taxonomic status. The following are important substances contained in fruits and their part in human nutrition and use for food purposes. The end of the theoretical part of bachelor thesis is about basic methods of determining the nutritional parameters of berries. In the experimental part solids content of the fruit. Furthermore soluble dry matter content, pH, titratable acidity, formol number, reducing sacharides and ascorbic acid by spectrofotometry were determined. Based on the results, juices were compared.
|
|
|
Basic chemical characteristics of juices from selected blackcurrant varieties
Maňásková, Eva ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This thesis deals with the basic characteristic of juices of the selected varieties of blackcurrant. The theoretical part presents the history and origin of this fruit cultivation, basic botanical description of each species and selected varieties and also features active substances contained in fruits. Conclusion the theoretical part then describes procedures basic methods of determining the various chemical parameters of fruits. In the experimental part was set tentative determination juice yield, soluble solids content, pH, titratable acidity and formol number. Based on the results were different varieties compared.
|
|
|
Burning pellets from non-wood biomass in boilers II
Linda, Matúš ; Baláš, Marek (referee) ; Zejda, Vojtěch (advisor)
Bachelor thesis is divided into four main chapters. The first chapter deals with issue of combustion of agropellets in boilers. This section specifies types of pellets, their production and problems of combustion in boilers associated with formation of emissions. The second chapter specifies valid legislation and emissions limits. The third chapter describes fuel analysis of agropellets samples. This includes an analysis in order to determine the properties and chemical composition of agropellets resulting in determination of gross heat and calorific value. The fourth chapter evaluates agropellets influence on boilers and emissions creation on the basis of data and knowledge. The results are compared with data of other commonly used solid fuel found in literature sources.
|
|
|
Corelation of transport and viscoelastic properties of hydrogels with diffusion gradient
Ščotková, Romana ; Sedláček, Petr (referee) ; Smilek, Jiří (advisor)
The aim of the presented bachelor thesis was to prepare hydrogels with diffusion gradient and to demonstrate the gradient structure of hydrogels in terms of viscoelastic and transport properties. With regard to potential biomedical applications, the cationic polysaccharide chitosan was selected for the preparation, especially for its antimicrobial and biocompatible properties. The resulting gradient hydrogels were subsequently characterized by oscillation tests to observe the differences using different concentrations and molecular weights of chitosan, crosslinking agent concentrations, dispersion environments for chitosan dissolution, and different gel crosslinking times. The samples were also subjected to drying experiments to confirm the gradient structure formed. The ability of the hydrogels to transport the active species was confirmed by visually evaluating the permeation of the anionic dye (bromothymol blue) during the gelation process. From the results obtained during the experimental part of the bachelor thesis it can be concluded that the viscoelastic properties of hydrogels can be modified by changing selected parameters during the preparation itself. It was also confirmed the assumption that with better mechanical properties of hydrogels there is a deterioration of transport properties. By controlled diffusion method, it was possible to prepare a hydrogel with a gradual gradient of crosslinking density, thus modifying the viscoelastic and transport properties.
|
|
|
Bioactive substances contained in elderberry pomace
Šimšová, Veronika ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the determination of selected chemical characteristics in the elderberry juice, compote and in the extracts of elderberry marc. The theoretical part describes the botanical characteristics of elderberry (Sambucus nigra L.) including its occurrence, the possibility of utilization of individual parts of the plant in the food industry and in the healing therapies and chemical composition of the berries. The biggest attention is given to the bioactive compounds contained in these fruits. The second chapter deals with the dry matter and the methods of its determination. The last chapter of the theoretical part describes vitamin C, its importance for the human organism and manual methods for determination of vitamin C. Among the selected chemical characteristics, set out in the experimental part, was the determination of reducing sugars by gravimetric method and Berthrand method, titratable acids, total anthocyanins by pH-differential method, total phenolic compounds by the Folin-Ciocalteu method and determination of the dry matter by drying and refractometric method. Analyzes have proven that extracts made of elderberry marc under suitable conditions have, in most cases, chemical characteristics comparable to the elderberry juice and compote. However, extracts are much better source of anthocyanic and phenolic compounds than juice and compote.
|
|
|
Sledování vybraných parametrů čistírenského kalu
Hirschová, Linda
This thesis deals with the evaluation and characterization of sludge parameters relevant to the drying process and subsequent energy recovery. The main parameters monitored are the dry matter of the sludge, the loss on ignition, the calorific value of the primary, thickened and dewatered sludge. Marginally, the paper also deals with the evaluation of pH, conductivity and oxidation-reduction potential. In particular, the characteristic of dewatered sludge entering the drying process is central. The dry matter of the dewatered sludge ranged from 13.5 to 25.7 %. The measured values of the calorific calorific value of the dewatered sludge ranged from 10.2 to 17.9 MJ∙kg-1, an assessment observed a dependency between the loss on ignition and the calorific value of the sludge. The impact of thickening (gravitational, mechanical) and stabilization (aerobic, anaerobic) sludge technology is taken into account in the evaluation. Part of the thesis deals with statistical evaluation of the effects of seasonality on monitored parameters.
|
|
|
Stanovení in vitro stravitelnosti sušiny a organické hmoty směsných krmných dávek s rozdílným zastoupením krmných surovin
Ursová, Lucie
The aim of this thesis was evaluvation of the digestibility of dry matter and organic matter by in vitro method in total mixed ration (TMR) with different representation of components. The gastrointestinal tract of ruminants with all its physiological requirements is described in the literary review. Furthermore, attention was paid to factors affecting the digestibility of feed and subsequent methods for determination of digestibility. The literary review was also focused on the characteristics and structure of TMR. TMR analyzes were determined by chemical methods and subsequently statistically evaluated in Excel and Statistica. The analysis took into account the chemical analysis, nutritional value and concentration of macroelements and microelements. 8 TMRs with different proportions of components were selected for analyzes, of which 6 were assembled for the peak of lactation, one for early lactation and one for the end of lacta-tion. All TMRs are designed for dairy cows with production capacity of over 9,000 l of milk.
|
|
|
Charakteristika nových hybridů silážní kukuřice
Stejskalová, Šárka
This bachelor thesis focuses on the characteristics of early maturing corn silage hybrids from the VP AGRO company. The selected hybrids were compared according to the yields of the green matter (t/ha), dry matter (t/ha and %) and according to the price level of seeds (Kč/SU). The data were collected from field trial records that took place between 2011 and 2022. These field experiments took place in the Czech potatoe agricultural sector in the Vysočina region at the following stands: Bobrová, Častrov, Horní Krupá, Okrouhlička, Počátky, Pohled, Pozovice, Radostín, Stonařov and Věž. Twelve hybrids were selected for the purpose of the study. The hybrids were subsequently divided according to the year of registration in the Czech Republic, followed by their detailed description and analysis. Based on the collected data, the following results were found. The total yields of green matter for all hybrids showed very similar and high values (50 t/ha). On the contrary the results of dry matter yields differed for each hybrid (16–18 t/ha). Additionally, similar fluctuations of dry matter in percent (34–38 %) were found. This high level of percentages of dry matter was caused by climate, soil conditions and different properties of individual hybrid. Regarding the economic comparison, the rising trend of the price level was confirmed, as is the case in the entire national sector. Seed prices have been affected by climatic, socio, political, and economic changes. One of the reasons for the price increase proved to be bad weather conditions (drought) in France, the state where the selected hybrids are bred.
|
|
|
Determination of nutritional values and antioxidant capacity of different edible roots
Ciffrová, Karolína ; Bendová, Agáta (referee) ; Němcová, Andrea (advisor)
This bachelor thesis deals with selected edible roots, their nutritional composition, antioxidant capacity and use in healthy eating. Eight selected edible roots were analyzed: type A, B and C potatoes, red potatoes, sweet potatoes, and purple potatoes were selected as representatives of potatoes. Jerusalem artichoke and cassava represent the other two root crops. The theoretical section of the thesis describes the basic characteristics of root crops, as well as the description and composition of the nutritional substances they contain, i.e. proteins, carbohydrates, fats, vitamins and antioxidant properties. The general characteristics of the methods used for analysis are also described here. The experimental part is based on specific analyses, procedures, results, chemicals and laboratory equipment used to determine the basic nutritional values and antioxidant capacity of these selected root vegetables. First, the total dry matter content was established to be about 23 % in the selected root crops. Higher dry matter content was determined for the cassava at 35 %. Crude protein content determined by the Kjeldahl method ranges from 6.5-9.9 %. The gravimetrically determined fiber in the given root crops was in the range of 0.27–0.91 %. The starch content is significantly higher in the cassava (46 %) than in other root crops. The inulin content was determined in sweet potatoes and Jerusalem artichokes instead of starch content; this value is significant for the Jerusalem artichoke (258.58 g/kg). Fat content in grams per 100 grams of dry matter was determined by Soxhlet extraction. Significant fat content was determined for sweet potatoes (12.6 g/100 g). From the extracted fats, the fatty acid profile was determined for individual root vegetables, such as the content of saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Total and reducing carbohydrates, determined by the spectrophotometric method, were measured separately in the peel and pulp of the root crops. Antioxidant capacity was determined using antioxidant activity values, polyphenol and flavonoid concentrations. Of the vitamins, vitamin C was determined, vitamin E only in type B, C and purple potatoes. For sweet potatoes, beta-carotene was determined to be 540.56 g/g. The measured and calculated results are plotted in graphs. Finally, there is a discussion of the conclusions of the individual methods.
|
|
|
Pepper quality in terms of piperine content
Lamplot, Marek ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
The aim of this bachelor's thesis was to determine the quality of pepper available in the commercial network of the Czech Republic. The quality of the pepper samples was determined based on the piperine content. Piperine was extracted from pepper samples using acetone and the extracts were subsequently analyzed using high-performance liquid chromatography with a mass detector. In all samples, the water content was determined by Karl-Fisher titration, and the piperine content in the samples was subsequently converted to dry matter. The content of piperine in pepper varied from 49 to 90 mg/g and met the requirements of the current legislation, which specifies a minimum piperine content of 4 % in pepper. Statistical analysis showed that there is a statistically significant difference between individual pepper samples in terms of piperine content, which points to the fact that pepper from different producers comes from different sources.
|
guest ::
