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Influence of beer protein on foam stability
Benda, David ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the influence of beer proteins, phenolic compounds, bitterness and selected metal ions on beer foam stability. The theoretical part describes beer foam from the physical aspect, beer foam stability and its measurement and the factors that positively or negatively influences the stability and quality of the beer foam. In the theoretical part are described selected proteins that influence beer foam. In theoretical part is described the origin and technological significance of proteins. The experimental part is dedicated to the measurement of beer foam stability with the NIBEM method, the analysis of total protein content, the analysis of total phenolic content, bitternes and element analysis of beer samples. Measured data indicated correlations between protein content, phenolic compounds content, bitterness and metal ions with the beer foam stability. The results show that proteins and phenolic compounds as isolated parameters don’t essentialy affect the beer foam stability. It was found out, that bitterness as isolated parameter influences the beer foam stability the most.
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Preparation and properties of agarose hydrogel with micellar domains
Sapárová, Alica ; Krouská, Jitka (referee) ; Pekař, Miloslav (advisor)
This diploma thesis was focused on the system of agarose hydrogels with micellar domains. Polysaccharide agarose was used for the preparation of hydrogel matrices. Septonex was chosen as a surfactant. The release of solubilizate from the agarose hydrogel matrix was studied with a hydrophobic dye Sudan III in order to obtain a model system of hydrophobic solubilized drugs. Sudan III was solubilized via surfactant´s micels. Subsequently, this micellar aqueous solution with the dissolved dye was used to prepare the agarose hydrogel. The system was prepared in the environment of deionized water and physiologic solution. The gradual release of the dye into deionized water and physiologic solution was studied for 22 days using the UV-VIS spectrophotometry method. It was found that after 14 days the concentration of the releasing dyes into the deionized water was decreased. The cause is that after 14 and 22 days there was a slight degradation of gels, which was detected using the rheology method. Using the rheology method it was also found that Septonex does not affect the gel formation process.
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Solubilization of water-insoluble vitamins into vesicular systems based on ionic amphiphilic pairs
Kolomá, Nikola ; Mravcová, Ludmila (referee) ; Mravec, Filip (advisor)
This thesis deals with the characterization and preparation of catanionic vesicular systems and their interaction with water-insoluble vitamins. Catanionic vesicles systems was prepared from two differently charged sufractants CTAB and SDS in formation ion pair amphiphile. Stability of vesicles was secured by adding cholesterol with positively charged surfactant DODAC. Were selected vitamin A and vitamin E for solubilization into these vesicles. The next part of this work was focused on determining the efficiency of incorporation these vitamins into the HTMA-DS vesicular system. The characterization of these systems was improved by measurement on a UV-VIS spectrometer, DLS and by HPLC with UV-VIS detector. During measurement by UV-VIS and HPLC the efficiency of solubilization of vitamin A and vitamin E into vesicles was determinated. In both cases higher efficiency was determinated for vesicles with incorporated vitamin A. Higher efficiency for both vitamins was determinated by HPLC. The reason is probably the higher sensitivity of the metod, work in labs with dark glass and preparing individuals samples into vials, which were inserted into the device for individual dosing by injector. The work serves primary evaluation results in view of the vesicular system for use in pharmaceutical application like carrier non-polar vitamins.
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Model delivery systems for poorly soluble drugs
Sapárová, Alica ; Holínková, Petra (referee) ; Pilgrová, Tereza (advisor)
The solubilizing capacity of micelle–hyaluronan system was studied using the UV-VIS spectrophotometry method. Septonex was chosen as a surfactant and four molecular weights of hyaluronan were used. Solubilization experiments with a hydrophobic dye Sudan Red G and Sudan III were performed in order to obtain a model system of solubilized drugs, which are also hydrophobic. The system was prepared in the environment of mili-Q water. The influence of the molecular weight of hyaluronan on the solubilizing ability has been studied. It was found that concentration of solubilized dyes increases by increasing concentration of micelles in the system and the molecular weight of hyaluronan affects the solubility of the dyes.
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Effect of the dry hopping of the stability of beer foam
Benda, David ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the influence of dry hopping on the stability of the beer foam. It was observed how this effect affected general characteristics of beer, the content of hop bitter acids, proteins, phenolic compounds, selected micro- and macro elements, organic acids and the stability od the beer foam. Theoretical part characterises raw the materials for beer production, the substances affecting the stability of beer foam and the beer brewing process. Furthermore the beer foam is described froam a physical point of view together with the steps of its formation and drainage as well as other phenomena that lead to its disappearance. A detailed description of used analytical methods is included. The experimental part illustrates the preparation of the model beer and the implementation of dry hopping with the Czech hop variety called Kazbek. Dry hopping was carried out on day 3, day 5 and day 10 with a 3 g/l and a 6 g/l hop dose. The prepared beer was subsequently analysed for general characteristics, the beer foam stability, bitter hop acids, phenolic compounds, protein, selected micro- and macroelements and organic acids. Based on the measured data, there were found correlations between the observed beer parameter and the stablity of the beer foam. The results revealed that dry hopping in beer increases the content of the phenolic compounds and bitter substances, but its effect on the beer foam stability is negative.
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Experimental study and modelling of the transdermal penetration of active species from gels
Palanová, Veronika ; Opatřilová, Radka (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with design and experimental study of transdermal transport of pharmaceutically active agents from gel matrices, which contain humic substance in its structure. A model absorption membrane was represented by the skin of pig´s earlobes. The study of the release of active substances and Lignohumte was performed due to the vertical diffusion cells. The amount of released humic substance was characterized by UV-VIS method and the amount of released active agent from gel matrix was determined by HPLC-DAD. The most interesting finding of this diploma thesis was that Lignohumate enhances transdermal transport of active agents and supports their release from gel samples to the particular environment.
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Stability of cross-linked collagen
Součková, Gabriela ; Vojtová, Lucy (referee) ; Jančář, Josef (advisor)
Teoretická část této bakalářské práce pojednává o obecných vlastnostech kolagenu, který je nejčastěji rozšířeným vláknitým proteinem v těle, o síťování kolagenu, které vede ke zlepšení mechanických i chemických vlastností, a o široce využívaných síťovacích činidlech, především 1-ethyl-3-(3-dimethylaminopropyl) karbodiimidu (EDC). Dále se zabývá několika metodami stanovení EDC ve vodném roztoku. Experimentální část je zaměřena na praktické stanovení množství EDC, které zůstalo ve vodě použité k promývání vzorků po síťování. Cílem bylo zjistit, jestli současně používaná metoda promývání je dostatečná pro jisté aplikace nebo je potřeba ji upravit. I přesto, že sloučenina EDC je prakticky netoxická, může způsobovat zbarvení kolagenních materiálů po sterilizaci ozařováním. Vzhledem k tomu, že nebylo zjištěno jaké množství EDC může ve vzorku zůstat nebo jestli je nezbytné vymýt veškeré EDC, je obtížné rozhodnout jestli je promývací metoda dostatečná nebo není. Navíc je potřeba brát do úvahy i ostatní vedlejší produkty síťování kolagenu. Nicméně cílem této práce bylo pouze zhodnotit účinnost vymývání EDC z kolagenních vzorků. Pro síťování byly použity tři různé koncentrace EDC a následně byly vzorky vymývány po různě dlouhou dobu. Takto bylo získáno 48 vodných vzorků, které byly následně třikrát spektrofotometricky stanoveny. Výsledně bylo zjištěno, že pro běžně používanou koncentraci síťovacího činidla (50 mmol.l 1 EDC) postačuje promývat vzorky po dobu 30 minut v roztoku hydrogenfosforečnanu sodného (Na2HPO3) a následně promývat ve vodě čtyřikrát po dobu 15 minut s výměnou vody při každém kroku. Po těchto krocích klesla koncentrace EDC v promývací vodě pod 1 mol . l-1, pro nižší koncentrace síťovacího roztoku byla dostatečná i kratší doba promývání. Výsledky této bakalářské práce jsou pouze předběžné, a proto by mělo následovat další zkoumání této problematiky.
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Interactions of pharmaceuticals with humic acids
Libiger, Jan ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
The bachelor thesis is focused on interaction of drugs with humic substances, which are part of organic soil matter. The results would help in understanding the behavior of drugs in soil and other natural systems. Three drugs were selected. Humic acid was selected as a sorbent, which was extracted from lignin, the lower one is assumed to be the same as that in organic soil. Based on a comparison of the measurement results using the UV-VIS method, it was determined how much the acid of the given drug is able to absorb and how much it is released back into the water. The theoretical part deals with the information about soil organic matter, with the information about humic substances, with the information about drugs such as ibuprofen, sulfamethoxazol or sulfapyridine. Furthermore, the theoretical part deals with methods of analysis.
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Beer bioflavouring by dry hopping using czech cultivars of hops
Gajdušek, Martin ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the influence of dry hopping on selected analytical and sensory properties of beer. The effect of dry hopping was observed using Czech hop varieties Kazbek and Uran, which were added to the wort during the main fermentation phase in doses of 3 and 6 gdm-3. The contact time of hops with wort was 3, 6 and 9 days. The experimental part describes the technology of preparation of the reference beer, in which dry hopping were subsequently performed. A parallel measurement was performed on each sample. In terms of the basic parameters of beer, the effect of dry hopping, especially its length, on the ethanol content was observed. With a longer period of dry hopping, the concentration of ethanol in beer increased. The higher alcohol concentration was also associated with a decrease in the apparent extract. In terms of color and pH of beer, the effect of dry hopping has not been proven. Elemental analysis performed by optical emission spectrometry with inductively coupled plasma revealed an increase in the concentration of calcium, magnesium, and iron due to dry hopping. No statistically significant difference was observed for manganese and barium compared to the reference. In terms of bitterness, a significant increase was identified in dry hopped beers compared to the reference, the value being dependent on the dose of hops used. The effect of the hop variety has not been proved. Concentrations of organic acids determined by ion-exchange chromatography with a conductivity detector were affected by dry hopping only in the case of lactic acid and acetic acid. An increase in lactic acid was observed compared to the reference, also related to the degree of fermentation. While in the acetic acid content the hop samples showed a lower concentration than the reference sample. The concentrations of myrcene, humulene and geraniol were determined by gas chromatography with a mass detector. These are volatile components of hop essential oils. Dry hopped samples recorded significantly higher concentrations of all aromatic substances compared to the reference. In terms of hop time, the highest concentrations were shown by samples hopped for three days. The results of the sensory analysis show that the overall best rated sample is a sample hopped with the Kazbek variety with a dose of 3 gdm-3 for three days. Beer which was dry hopped for the shortest time also showed the lowest intensity of bitterness, which was perceived positively.
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