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Use of microcalorimetry in the study of hydration of biopolymers
Bola, Tomáš ; Smilek, Jiří (referee) ; Krouská, Jitka (advisor)
This master thesis deals with the using of microcalorimetry in the study of hydration of biopolymers. Lactose has been selected together with the other biopolymers although it is not among biopolymers but disaccharides. Selected biopolymers are alginate, dextrane, chitosan and hyaluronan of two molecular weights. Lactose has been selected for these purposes mainly because it is a model example to determine whether or not the reaction to moisture between the other samples and the saturated salt solution occurs. The biopolymer hydration study, as opposed to the commonly used perfusion calorimetry method using the possibility of measuring with adjustable moisture has been used an isothermal microcalorimetry method where at two constant temperatures the reaction of the sample to the different moisture released by the saturated salt solution was monitored.
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The use of alternative coagulants in water treatment
Hofmanová, Lucie ; Zelený, Zdeněk (referee) ; Kučera, Tomáš (advisor)
This bachelor's thesis deals with the use of alternative coagulants in water treatment. The first theoretical part mentions types of water treatment for the individual categories of raw water, related laws and ordinances. After that thesis describes the principle, mechanisms of coagulation and factors influencing the process. It analyses the jar test procedure performed within the experimental part of the bachelor's thesis. One chapter deals with polymers and metal coagulants based on aluminium and iron commonly used in water treatment. The chapter includes more detailed description of natural polymers moringa oleifera and chitosan. These two coagulating agents and aluminium sulfate were used in the second experimental part of the bachelor's thesis. Several sets of the jar test were performed in order to investigate the efficiency of chosen coagulants on the removal of turbidity from water. The thesis concludes with a comparison and evaluation of the results. Photos taken during the jar test can also be found at the end of the bachelor's thesis.
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Hydration of biopolymers
Šméralová, Ester ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
Presented bachelor's thesis focuses on the study of hydration of selected biopolymers – humic acids, chitosan, hyaluronic acid (low molecular weight and high molecular weight) and dextran. Thermogravimetric analysis TGA is used t determine the original moisture content of the samples. Two calorimetric methods were used for subsequent observations of changes in their chemical and mechanical properties in the presence of water – differential scanning calorimetry DSC and perfusion calorimetry.
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Application of microencapsulation techniques in development of novel controlled-release systems.
Karásková, Iva ; Mravec, Filip (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with application of microencapsulation techniques in development of hydrogel controlled-release systems in which the main role is played by humic acids, biopolymer chitosan, compound fertilizer NPK and 3-indoleacetic acid. This paper continues my bachelor thesis topic about utilization of polyelectrolyte complexes. The aim of this work was to develop a literature review focusing on the microencapsulation techniques and according to its results optimize the method. Microencapsulation was performed with a commercial encapsulator BUSCHI B-395 Pro and a release of individual components into a water was measured. An amout of released substances was measured by UV-VIS method and HPLC analysis. Practical part also included testing of repeated swelling and drying. It was found that suitable composition and combination of ingredients form hydrogels for further use in agriculture.
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Preparation and characterization of hydrogels based on cationic biopolymer
Tesařová, Barbora ; Mravec, Filip (referee) ; Smilek, Jiří (advisor)
Presented thesis deals with the preparation and characterization of hydrogels based on positively-charged biopolymer and negatively-charged tenside. As an appropriate representative of positively-charged polymer was chosen chitosan, because of his biocompatibility and biodegrability, and N,N,N-trimethylchitosan, which was synthetised from chitosan in this diploma thesis. The final product of synthesis was characterised by SEC-MALS, elemental analysis, infrared spectroscopy and nuclear magnetic rezonation. Interactions between these polymers and representatives of negatively-charged tensides, which are sodium dodecylsuphate and sodium tetradecylsulphate, were investigated. The main method used in this thesis was rheology, through it were investigated prepared hydrogels based on chitosan and tensides and also prepared microgels based on N,N,N-trimethylchitosan and tensides. The interactions between polymers and tensides have been proved.
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Hydrogels based on cationic polyelectrolytes
Jarábková, Sabína ; Lehocký,, Marián (referee) ; Pekař, Miloslav (advisor)
This diploma thesis deals with the study of physical hydrogels based on positively-charged polyelectrolyte. The study is to investigate the interaction of selected positively-charged polyelectrolytes with oppositely charged surfactants in water and in physiologicla saline solution (0.15 M NaCl). The influence of the process for preparing hydrogels. Hydrogels were prepared by dry or wet. Were tested solubilization abilities hydrogels prepared using the hydrophobic dye oil red O were also measured rheological properties of the hydrogels prepared using frequency oscillatory tests and flow tests, depending on the concentration of the polymer or surfactant. For the rheological experiments suggest that chitosan is capable of forming rigid hydrogels with better mechanical properties than the dextran in the presence of both surfactants. Selected samples were also carried out experiments using fluorescent sold prodan, nile red and -naphthol as fluorescent probes. And in selected experiments was determined by solids content in percentage depending on the concentration used polyelectrolytes or surfactants.
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Study of interactions of pigments with biopolymer chitosan
Kolesa, Pavel ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This master's thesis was focused on the study of interaction of some organic azo dyes (model diffusion probes) with cationic biopolymer chitosan. This interactions were realized via diffusion processes in hydrogel media based on thermoreversible agarose. The main aim was study of influence of pH of solution on the diffusion process. Interactions of used dyes are based on electrostatic character. The aminogroup of chitosan interacts with the functional group of chosen dyes (anionic sulfonic group) and thus affects the process of diffusion. The model diffusion compounds were chosen organic anionic dyes Chicago sky blue 6B (C.I. 24 410), Sirius red (C.I. 35 780) and Reactive blue 49 (C.I. 621 526). The important content of this diffusion method is a monitoring of the time progression of diffusion profile by UV-VIS spectrophotometry. The presented work follows the bachelor thesis and shows comprehensive view of the reactivity of chitosan and its behavior in different systems. Unsteady diffusion in cuvettes appears to be a universal method for the study of reactivity of biopolymers and for the study of transport processes in hydrogel media. The diffusion method is universal, easy and cheap.
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Microrheology in colloid systems
Hradecká, Lucie ; Burgert, Ladislav (referee) ; Mravec, Filip (advisor)
This master thesis is focused on the evaluation of the influence of particle surface properties on the results of microrheological measurements with biopolymer solutions. Hyaluronan has been chosen as negatively charged polymer, chitosan as positively charged polymer and glycerol and its solutions of various concentrations were used as homogenous model systems. Dynamic light scattering and single particle tracking microrheology were chosen from passive microrheological techniques. Particles with various surface modifications (neutral, positive surface charge and negative surface charge) were used for the experiments. The results of microrheological techniques were then compared with classic rheology and moreover the glycerol results were compared with tabulated values.
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Removal of Selected Components from the Aquatic Environment by Coagulation Process
Měřínská, Zuzana ; Márová, Ivana (referee) ; Janda, Václav (referee) ; Mergl, Václav (referee) ; Vávrová, Milada (advisor)
This thesis deals with coagulation treatment of surface water with content of humic matters, drug residues and turbidity. Commonly used coagulants (ferrous and aluminous sulphate) and natural biopolymer based on chitosan that not yet used in the Czech Republic had been studied. The aim of this work was to found the optimal application of chitosan in water treatment and comparison of its coagulation efficiency with standard inorganic coagulants. Theoretical part of the thesis contains occurrence, classification, composition, properties and importance of humic matters and drug residues and furthermore properties of chitosan and its using in water treatment. Experimental part summarizes the obtained results from the laboratory coagulation tests with inorganic coagulants and with chitosan leading to determination of its optimal dose. Other coagulation experiments were focused on finding the possibilities of combine the two coagulants (ferrous sulphate and chitosan) and to find their optimum doses and suitable ratio. The influence of pH on water treatment with using coagulation was also studied.
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Encapsulation of selected natural extract for food application.
Vyskočilová, Terezie ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
This diploma thesis deals with encapsulation of natural extracts. In the theoretical part the methods of encapsulation, materials for particle preparation, as well as application of encapsulation techniques in food industry were described. In experimental part selected natural extracts of propolis, green barley and probiotics were characterized. There substances were encapsulated into alginate and chitosan. In the total of 25 types of prepared particles long-term stability in some model physiological conditions as well as in four different model foods was evaluated. Additionally, stability of selected particles in several real milk-based products was followed too. The stability of particles was determined spectroptohometrically. In natural extract a content of polyphenols, proteins, chlorophylls, as well as total antioxidant activity were analysed. To analysis of probiotics optical and fluorescence microscopy were used. In propolis and green barley antimicrobial activity was tested too. Moreover, in the sample of propolis also cytotoxic assay was applied. Agar-chitosan was chosen as the best shell material for propolis due to its optimal stability in model physiological conditions as well as model foods. Liposomes were evaluated as unstable and were not recommended for further application. As the suitable shell material for powdered green barley starch-alginate (rate 1:4) and agar-chitosan were proposed, while the second one showed better stability for released proteins. Agar-chitosan shell material was usable for fresh green barley too. For probiotics encapsulation alginate or alginate-starch were chosen because of their porosity and possibility of nutrients diffusion. In real foods the best results were reached with application of probiotic particles into milk. Coencapsulation of powdered barley and probiotics did not confirm inhibition of culture growth. Neither the antimicrobial effect of propolis and barley nor the cytotoxic effect of propolis were confirmed.
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