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Preparation of edible antimicrobial packaging
Kozubová, Petra ; Dzurická, Lucia (referee) ; Skoumalová, Petra (advisor)
This bachelor’s thesis is focused on preparation and characterization of eatable packaging. Eatable packaging consists of two components, antimicrobial component and base of packaging. The task of eatable packaging is to protect product against antimicrobial attack and to extend durability of the product. As antimicrobial components were used water and oil extracts of several herbs (mint, nettle, lavender, cinnamon, cloves, vanilla, ginger and rhinoceros). Oil extracts were also encapsulated into liposomes for better application. Firstly, concentrations of polyphenoles and antioxidants of extracts were determined. Oil extract of clove contained the highest concentration of both determined substances. Encapsulation efficiency, stability and size of liposomes were tested too. All prepared liposomes were stable and relatively of the same size. Also high encapsulation efficiency was observed. Next, antimicrobial activity of prepared extracts and liposome particles against yeast Candida glabrata and two bacteria strains Escherichia coli and Staphycococcus epidermidis was tested and the high antimicrobial activity reported mainly all tested liposomes. Then alginate, chitosan and carboxymethylcellulose and their combinations respectively were used as bases of packaging. Created film had to meet several parameters, especially suitable sensory properties such as pleasant taste and smell, as well as invisibility, gloss, affordability and suitable manipulability. Combination of 2% carboxymethylcellulose and 1% alginate in a ration of 2:1 with liposomes of mint as antimicrobial component achieved the best results.
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Immobilization of selected glycanohydrolases
Reichstädter, Marek ; Trachtová, Štěpánka (referee) ; Omelková, Jiřina (advisor)
The theoretical part of this thesis deals with cellulolytic enzymes, their microbial producers, the possibilities of using such enzymes in the industry and how can be enzymes - not only cellulolytic - immobilized. Experimental part examines the preparations created by immobilizing various amounts of the commercially used cellulolytic complex Cellulast 1.5L onto various synthetic carriers made of polyethylene terephthalate - commercially used Sorsilen, PET carrier and glutaraldehyde-treated PET carrier. Enzyme activity of these preparations was determined by Somogyi - Nelson method by spectrophotometry. For the highest activity immobilized preparation was determined the temperature- and the pH-optimum. The difference in effects change between the free and immobilized enzyme by measuring viscosity decrease of the substrate depending on the degradation of glycosidic bonds was also studied.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Quantification of the stabilizing effects of cyclodextrins on volatile biocides using spectral methods
Konovalova, Olga ; Jindřich, Jindřich (advisor) ; Smrček, Stanislav (referee)
This bachelor's thesis deals with monitoring the stability of chlorine dioxide of native and methylated cyclodextrins in the presence of hydrogenating agents. It is believed that using cyclodextrins and carboxymethylcellulose can improve the stability of chlorine dioxide and slow its release from the solution. UV spectroscopy was used to monitor any changes in absorbance over time and to determine the concentration of chlorine dioxide in the solution. When the rate of chlorine dioxide loss from solution was monitored, it was found that the presence of native and permethylated cyclodextrins slowed the loss of chlorine dioxide from solution, with the slowest decomposition observed in the presence of permethylated cyclodextrin. The addition of carboxymethylcellulose to the chlorine dioxide solution slows the rate of chlorine dioxide loss from the open vial the most, by almost three times, compared to ClO2 itself. This study's results can help optimize chlorine dioxide product formulation for various applications and contribute to the development of more stable and effective chlorine dioxide- based products that can be used to control or eliminate harmful microorganisms in different environments. Key words: chlorine dioxide, CDS, cyclodextrins, carboxymethylcellulose, biocides, UV-Vis...
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Preparation of edible antimicrobial packaging
Kozubová, Petra ; Dzurická, Lucia (referee) ; Skoumalová, Petra (advisor)
This bachelor’s thesis is focused on preparation and characterization of eatable packaging. Eatable packaging consists of two components, antimicrobial component and base of packaging. The task of eatable packaging is to protect product against antimicrobial attack and to extend durability of the product. As antimicrobial components were used water and oil extracts of several herbs (mint, nettle, lavender, cinnamon, cloves, vanilla, ginger and rhinoceros). Oil extracts were also encapsulated into liposomes for better application. Firstly, concentrations of polyphenoles and antioxidants of extracts were determined. Oil extract of clove contained the highest concentration of both determined substances. Encapsulation efficiency, stability and size of liposomes were tested too. All prepared liposomes were stable and relatively of the same size. Also high encapsulation efficiency was observed. Next, antimicrobial activity of prepared extracts and liposome particles against yeast Candida glabrata and two bacteria strains Escherichia coli and Staphycococcus epidermidis was tested and the high antimicrobial activity reported mainly all tested liposomes. Then alginate, chitosan and carboxymethylcellulose and their combinations respectively were used as bases of packaging. Created film had to meet several parameters, especially suitable sensory properties such as pleasant taste and smell, as well as invisibility, gloss, affordability and suitable manipulability. Combination of 2% carboxymethylcellulose and 1% alginate in a ration of 2:1 with liposomes of mint as antimicrobial component achieved the best results.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Immobilization of selected glycanohydrolases
Reichstädter, Marek ; Trachtová, Štěpánka (referee) ; Omelková, Jiřina (advisor)
The theoretical part of this thesis deals with cellulolytic enzymes, their microbial producers, the possibilities of using such enzymes in the industry and how can be enzymes - not only cellulolytic - immobilized. Experimental part examines the preparations created by immobilizing various amounts of the commercially used cellulolytic complex Cellulast 1.5L onto various synthetic carriers made of polyethylene terephthalate - commercially used Sorsilen, PET carrier and glutaraldehyde-treated PET carrier. Enzyme activity of these preparations was determined by Somogyi - Nelson method by spectrophotometry. For the highest activity immobilized preparation was determined the temperature- and the pH-optimum. The difference in effects change between the free and immobilized enzyme by measuring viscosity decrease of the substrate depending on the degradation of glycosidic bonds was also studied.
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