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Production and characterization of protein isolates from different kinds of bran
Vybíral, Lukáš ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the use of various types of bran as a by-product in the milling of cereals. Mills create a huge amount of this material per year. The most common way of processing bran is mostly incineration and to a lesser extent it is used as feed for livestock. Depending on the type of cereal, bran contains 10-20% of protein, which disappears from the food chain due to combustion. Within the framework of sustainability and valorisation of waste, which has recently been largely discussed, great emphasis is placed on waste minimization whether in the field of its production or further processing. Due to the relatively high protein content, bran appears to be a suitable starting material to produce protein supplements. Proteins can be extracted from bran based on their different solubility at different pH. In the alkaline method, the proteins are first dissolved in an alkaline pH and then precipitated in an acidic medium. Lyophilization is followed by characterization of the extract in terms of yield, protein content, moisture, amino acid profile and digestibility. The highest yield was obtained with the oat bran isolate (13,5 ± 0,6 g of isolate per 100 g of bran). In terms of protein content, the best protein isolate was also obtained from oat bran (95,2 ± 0,4% protein in the isolate). Another determination was the analysis of the amino acid profile, in which a high content of arginine was found in all analyzed protein isolates from bran. Determination of digestibility showed very good digestibility of all produced protein extracts from bran.
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Determination of mercury in selected fish species and in fish products
Kroupová, Kateřina ; Ing.Tomáš Gregor, Ph.D. (referee) ; Diviš, Pavel (advisor)
Theoretical part of the master thesis deals with the occurrence of different mercury species in the environment and describes analytical methods used for determination of mercury in biological samples. In practical part of the master thesis mercury concentration in 14 samples of selected fish and fish product was determined using single purpose absorption spectrometer AMA 254. Measured results were statistically processed and consulted with EU legislative norm.
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Speciation and fractionation analysis of metals in agricultural soils
Lepař, Petr ; Mládková, Zuzana (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the procedures and analytical techniques associated with speciation analysis and fractionation of metals in agricultural soils. The first part defines the basic concepts related to speciation, fractionation, soils and elements contained within it. The following chapters describe procedures of samples withdrawal and its adjustment including a description of some methods used for the purpose of extraction, fractionation and speciation analysis. The last chapter is devoted to listing of some separation techniques and instrumental methods used for the purposes of speciation and fractionation.
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Determination of selected nutritional parameters in the fruit of the plant genus Ribes
Ledvina, Vojtěch ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis focuses on the small fruit representatives from the plant genus Ribes L. - currant, gooseberry and jostaberry. The beginning of theoretical part describes history of cultivation and basic botanical description of individual cultivars. The next part describes important substances contained in fruit as well as their importance in human diet and it also describes some basic products made of the Ribes L. genus representatives. The final section of the theoretical part contains basic principal of determination of individual nutritional parameters. In the experimental part several nutritional parameters were determined including dry matter, soluble solids, pH, titratable acids, formol number, reducing sugars and total phenolics. Individual species and cultivars were compared based on the results.
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Determination of total protein, carbohydrates and polyphenols in beer
Dostálová, Blanka ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
This master‘s thesis deals with the analysis of 65 different beers, with a focus on finding differences between Czech tap ales, lagers Czech, Czech special beers and foreign beers. Czech beers were compared by the results of analysis among beers bearing the indication "Czech beer" and the group without this indication. The total amount of proteins, polyphenols and carbohydrates was determined using UV-VIS spectrometry. The history of brewing, the nature and types of Czech beers and protected geographical indication "Czech beer" were described. Raw materials for beer production and brewing technology have been listed and described. In the last part of the research, components of beer and the principle of the UV-VIS spectrometry have been specified. Th determination of total protein was performed using Hartree-Lowry method, which is based on two-component reagent. The first component is the biuret agent, the second component is the Folin-Ciocalteau reagent for phenols. Determination of the polyphenols has been carried out by the Folin-Ciocalteau reagent and total carbohydrates were determined spectrophotometrically according to the Analytica EBC using anthron agent. The results were statistically processed and evaluated in the final part.
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Determination of basic chemical characteristics of blackberry pulp
Pilátová, Anna ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with determination of selected chemical characteristics of juice, pulp and extract prepared from blackberry of two species, from The Czech Republic and Ukraine. The theoretical part contains the botanical characteristics of blackberry, the content of active substances and possibilities of use of blackberries in the food industry. The following chapters focus on the description of phenolic substances and the determination of pH and titration acidity of fruit juices by manual methods. In the experimental part, two extraction solvents were first compared for extraction of anthocyanins from blackberry moldings. Furthermore, the selected chemical and physical properties of extracts, juice and pulp from blackberries were determined. The analysis was carried out for blackberries from the Czech Republic and Ukraine. A 1 : 1 mixture of distilled water and ethanol was a better extraction solvent for the content of anthocyanins. After 14 hours of maceration 150.4 mg of anthocyanins was obtained from 100,0 g of blackberry moldings Extract from blackberry moldings has been determined to have a much higher concentration of anthocyanins than juice and pulp. The extract of Ukrainian blackberries contained 197.4 mg CGEdm-3 and extract of Czech blackberries 150.4 mg CGEdm-3. Also phenolic substances had the highest concentration in extracts. Ukrainian blackberries contained 3501.9 mg GAEdm-3 and Czech blackberries contained 3256.1 mg GAEdm-3.
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Study of organs of mice in inhalation experiments
Vrlíková, Lucie ; Diviš, Pavel (referee) ; Dočekal, Bohumil (advisor)
The diploma thesis is devoted to study potential risks for living organisms resulting from inhalation of nanoparticles of chosen heavy metals. The main aim of this work is the investigation of organs from experimental white mice after their guided inhalation of lead nanoparticles. The samples of liver and lungs from these animals are taken in time periods during the inhalation experiments and processed by specific methods for their evaluation. After pressurized microwave assisted decomposition of selected samples of mice organs in high purity concentrated nitric acid the content of lead is determined by atomic absorption spectrometry with electrothermal atomization. Furthermore, the changes are monitored using the microscopy of histological slides stained with hematoxylin-eosin. The results of both approaches are evaluated and compared within the frame of this work.
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Analysis of wine by modern analytical methods
Škařupa, Přemysl ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This work is dedicated to the analysis of wines using modern analytical methods. The theme is divided into two chapters. The first part deals with the chemical composition of wine from major components to the elements in trace amounts. The second part gives an overview of the most important modern analytical methods used for analysis of individual compounds in the wine and evaluated these methods in term of various parameters.
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Beer foam stabilization using biosurfactants
Jandrtová, Sabina ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis focuses on a research of the foam stability of the beer. We specifically observed the influence of ethanol and surface tension on the foam stability, and influence of ethanol and surface tension on the height of the foam. It was observed the influence of the hop acids in non-alcoholic beers. Furthermore, different biosurfactants were added into to the beer to observe better stability of the foam. The theoretical part of this work describes the foam from the physical aspect. There are described fourth key events involved in foam formation. Then it focuses on the beer foam – its structure, substances that influence its behavior and measurement of the foam stability. In this part there are described biosurfactants as well – their characteristics, qualities, distribution and applications. The experimental part is dedicated to the influence of ethanol, surface tension, the amount of iso- acids on foam stability in beer. There is observed the influence of biosurfactants of the foam stability and surface tension, which are added into to the beer. For the measurement of the foam stability was used the Rudin method. Liquid chromatography with DAD detector was used for the measurement the amount of the hop acids. The surface tension was determined by tensiometer. According to the results addition of ethanol changed the characteristics of the foam stability, but it’s not easy to find correlation between the increasing amount of ethanol and its stability. It was found out, that there is connection between the amount of ethanol and surface tension. On the other hand, there is not much connection between the surface tension and foam height. Within the framework of addition of biosurfactants was observed, that these foaming agents interacted the surface tension of the beer (lowering), however these agents accelerated the fall of the beer foam.
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