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Utilization of waste banana peels for packaging materials
Vachta, Jonáš ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with isolation of cellulose from waste banana peels and it’s use as a filler in composite films. The aim of this work was to prepare a bioplastic capable of being an eco-friendly alternative to conventional polymers with a potential for application in the packaging industry. The cellulose was isolated from banana peels using a method combination of alkalic and acidic hydrolysis and bleaching by sodium chlorite. The samples after isolation were characterised by Fourier transform infrared spectroscopy (FT-IR) and their average particle size was determined by microscope observation. Subsequently, composite films were prepared using agar and starch matrix, glycerol as plasticizer and isolated cellulose as filler in various concentrations to assess the effect of added cellulose on the properties of the resulting bioplastics. Characterization of the prepared bioplastics included FT-IR measurement, surface examination by a scanning electron microscope (SEM) and the determination of mechanical properties by measuring tensile strength, elongation at break and Young’s modulus. It was found that the addition of cellulose from banana peels has a positive effect on the mechanical properties of all prepared agar- or strach-based composites, with the exception of elongation at break in agar films, where there was a slight decrease compared to the reference films.
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Optimization of the Preparation of Thin Hydrogel Layers Based on Biocompatible Polymers
Vacková, Barbora ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
The aim of this master thesis deals with the optimization of the preparation of thin hydrogel films based on polyvinyl alcohol (PVA) with the possibility of incorporating suitable additives (polyelectrolytes, plasticizers, etc.) into the structure of the prepared film to modify its properties. DEAE-Dextran hydrochloride and polyglutamic acid (PGA) were used as polyelectrolytes. The basic characterization of the properties was performed on modified films, which were compared with pure PVA films. The films were characterized by thickness, swelling ability, barrier properties, tensile properties, specific surface area, antimicrobial tests, and thermogravimetric analysis. The swelling ability of PVA/PGA films was very high, which may be a disadvantage for their use in the packaging industry. Swelling increases the amount of water in the matrix of the PVA film, what leads to a higher growth of microorganisms and to degradation of thin film. The water vapor transmission rate was greatly affected by the addition of a plasticizer. The small specific surface area of the films indicates a smooth surface that promotes good barrier properties. Films with the addition of a plasticizer showed relatively good mechanical properties. The values of tensile strength, elongation and elastic modulus were comparable to commercially available films such as polypropylene (PP) or polyethylene (PE). Based on all experiments, PVA, PVA/DEAEDextran films and their variants with the addition of glycerol as a plasticizer were evaluated as the best candidates for the use of these films as packaging materials. The follow-up work could be dealing with the optimization of PVA films for oxygen permeability. Furthermore, the possibilities of using these films in the packaging industry based on the relative humidity of the environment, could be defined as other interesting area of future research.
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Uchovatelnost zeleninových salátů minimálně zpracovaných
Němcová, Barbora
This bachelor thesis is focused on shelf life of minimally processed salads. Opening part of thesis deals with vegetable varieties used in these salads, packaging materials and a modified atmosphere, which is used for preservation. Next part contains practical experiment of storing two kinds of cabbage packed in vacuum and the range of products found in chain stores in the Czech Republic and abroad.
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Utilization of waste banana peels for packaging materials
Vachta, Jonáš ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with isolation of cellulose from waste banana peels and it’s use as a filler in composite films. The aim of this work was to prepare a bioplastic capable of being an eco-friendly alternative to conventional polymers with a potential for application in the packaging industry. The cellulose was isolated from banana peels using a method combination of alkalic and acidic hydrolysis and bleaching by sodium chlorite. The samples after isolation were characterised by Fourier transform infrared spectroscopy (FT-IR) and their average particle size was determined by microscope observation. Subsequently, composite films were prepared using agar and starch matrix, glycerol as plasticizer and isolated cellulose as filler in various concentrations to assess the effect of added cellulose on the properties of the resulting bioplastics. Characterization of the prepared bioplastics included FT-IR measurement, surface examination by a scanning electron microscope (SEM) and the determination of mechanical properties by measuring tensile strength, elongation at break and Young’s modulus. It was found that the addition of cellulose from banana peels has a positive effect on the mechanical properties of all prepared agar- or strach-based composites, with the exception of elongation at break in agar films, where there was a slight decrease compared to the reference films.
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Optimization of the Preparation of Thin Hydrogel Layers Based on Biocompatible Polymers
Vacková, Barbora ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
The aim of this master thesis deals with the optimization of the preparation of thin hydrogel films based on polyvinyl alcohol (PVA) with the possibility of incorporating suitable additives (polyelectrolytes, plasticizers, etc.) into the structure of the prepared film to modify its properties. DEAE-Dextran hydrochloride and polyglutamic acid (PGA) were used as polyelectrolytes. The basic characterization of the properties was performed on modified films, which were compared with pure PVA films. The films were characterized by thickness, swelling ability, barrier properties, tensile properties, specific surface area, antimicrobial tests, and thermogravimetric analysis. The swelling ability of PVA/PGA films was very high, which may be a disadvantage for their use in the packaging industry. Swelling increases the amount of water in the matrix of the PVA film, what leads to a higher growth of microorganisms and to degradation of thin film. The water vapor transmission rate was greatly affected by the addition of a plasticizer. The small specific surface area of the films indicates a smooth surface that promotes good barrier properties. Films with the addition of a plasticizer showed relatively good mechanical properties. The values of tensile strength, elongation and elastic modulus were comparable to commercially available films such as polypropylene (PP) or polyethylene (PE). Based on all experiments, PVA, PVA/DEAEDextran films and their variants with the addition of glycerol as a plasticizer were evaluated as the best candidates for the use of these films as packaging materials. The follow-up work could be dealing with the optimization of PVA films for oxygen permeability. Furthermore, the possibilities of using these films in the packaging industry based on the relative humidity of the environment, could be defined as other interesting area of future research.
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Klasifikace korozního poškození historického olova a systém prostředků pro jeho konzervaci
Kouřil, Milan ; Ďurovič, Michal ; Bartl, Benjamin ; Strachotová, Kristýna Charlotte ; Msallamová, Šárka
Mnohé muzejní a archivní instituce se v současnosti potkávají s problematikou koroze olověných sbírkových předmětů, uložených v depozitářích, způsobenou citlivostí olova vůči těkavým organickým sloučeninám (VOC), zejména vůči kyselině octové. Zvláštní skupinou těchto olověných předmětů jsou olověné buly (kovové pečeti), které bývají obvykle připojeny k pergamenovým listinám pomocí textilního závěsného materiálu. Metodika zavádí systém kategorizace korozního poškození olověných pečetí a hodnocení podmínek jejich uložení a navrhuje postupy konzervačních opatření vhodné pro možné varianty výsledky průzkumu stavu pečetí a expozičních podmínek. Navržené konzervační postupy jsou založeny především na eliminaci agresivních složek prostředí volbou vhodných obalových materiálů a použitím sorbentů.
Fulltext:  PDF; PDF
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Testování antimikrobiální aktivity obalových materiálů s rostlinnými extrakty proti bakteriím rodu Enterococcus
Maňáková, Simona
This thesis deals with testing of antimicrobial activity of plant essential oils as part of packaging systems for foodpackaging against bacteria genus Enterococcus. The first literature part is focused on characteristic of genus Enterococcus and his possible apperace in food and his negative effect on human health. Next topic of literature section is targeted on using plants as producers of essential oils and their use in food industry as active compounds with antimicrobial and atifugal activity. This includes also characteristic of selected aromatic plants growing in our geographical conditions. Last part of literature section is introduction of characteristic of packaging materials and theirs big importance in food industry. Practical part of this thesis is dealing with testing of packaging materials containg essential oils on theirs surface against E. faecalis. Another part of this experiment is testing these antimicrobial packaging materials on selected foods in this case meat product following with microbiological analysis of selected bacteria.
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Ftaláty v potištěných a nepotištěných obalech masných výrobků
Lavingrová, Veronika
The diploma thesis is focused on the determination of the content of phthalates (PAE) in printed and non-printed plastic packaging materials for meat products. There were analyzed 30 package samples. The sample area was 1 dm2. Concentrations of dibutyl phthalate (DBP) ranged from undetectable values (< 0.1) to 72.6 ug.dm-2 of the sample surface in printed packaging materials. In non-printed wraps it was from undetectable values (< 0.1) to 67.7 ug.dm-2 of the sample surface. Concentrations of di-2-ethylhexyl phthalate (DEHP) ranged from undetectable values (< 0.1) to 98.7 ug.dm-2 of the sample surface in printed packaging materials. In non-printed wraps it was from undetectable values (< 0.1) to 60.3 ug.dm-2 of the sample surface.
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Biodegradabilní obalové materiály
Smutný, Roman
This bachelor thesis is focused on the issue of biodegradable materials, especially with regard to packaging materials. They try to approach this issue and make information about these materials. In this work we find the distribution and history of classical packaging materials as well as the division of biodegradable materials. For better presentation of the packaging, photographs are included in the work.
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Uchovatelnost zeleninových salátů minimálně zpracovaných
Němcová, Barbora
This bachelor thesis is focused on shelf life of minimally processed salads. Opening part of thesis deals with vegetable varieties used in these salads, packaging materials and a modified atmosphere, which is used for preservation. Next part contains practical experiment of storing two kinds of cabbage packed in vacuum and the range of products found in chain stores in the Czech Republic and abroad.
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