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Biodegradable plastics
Schifferová, Zuzana ; Jan, Vít (referee) ; Molliková, Eva (advisor)
The aim of this bachelor theses is to discuss the process of biodegradation occurring with biodegradable polymers including factors affecting this process. The theses also introduces some types of biodegradable plastics including their properties. At last it discusses waste management of these plastics and their ecological impact.
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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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Adhesion of the Hydrogels based on Poly(vinylalcohol)
Přibyl, Jiří ; Trudičová, Monika (referee) ; Kalina, Michal (advisor)
This bachelor thesis was focused on the study of adhesion properties of hydrogels based on polyvinyl alcohol using a rheometer. The used hydrogels were divided into three groups, physical, chemical, and modified with starch, PEG or gelatin. Subsequently, the adhesion properties of the hydrogels were determined using a pull off test measured on a rheometer. From the experimental results, the dependences of the adhesion properties on various parameters such as concentration, molecular weight, freezing / thawing process, amount of glutaraldehyde addition and on the type and ratio of added additive were determined. From the following results, it was found that starch is suitable as an additive for increasing the adhesion properties, and on the other side, PEG can be used to reduce the adhesion properties.
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Industrial production of ethanol
Flajs, Roman ; Zichová, Miroslava (referee) ; Omelková, Jiřina (advisor)
This bachelor thesis deals with ethanol production for food and car industry. The aim of this work is to give a summary of different kinds of raw material especially lignocelluloses and microorganisms used for its processing and fermentation. The thesis focuses especially on technological process of ethanol production and the utilization of different materials for fuel production.
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Solubility control of biodegradable starch-based packaging
Krobot, Štěpán ; Ondreáš, František (referee) ; Lepcio, Petr (advisor)
This bachelor thesis deals with the preparation and testing of biodegradable films based on starch. The aim of the thesis is laboratory preparation of foils based on various types of starch, glycerol, polyvinylalcohol and with the addition of plasticizer – citric acid. Four different types of starch and two types of polyvinyl alcohol were used. In the first series of samples, the ratio of added glycerol to starch content was varied. Samples in the second series were prepared in the same ratios, but with different PVA. A citric acid solution was added into the last series of samples. The second aim of the thesis, after pressing the films, was to determine their solubility and stability in aqueous media depending on the ratio between added glycerol to starch content, the type of polyvinylalcohol used, and the addition of citric acid to the mixture. It has been found that citric acid appears to affect the chemical structure of the films and thus their solubility in aqueous media as well as their mechanical properties. Fourier-transform infrared spectroscopy (FTIR) was used to study the structure of the films and to elucidate its effect on solubility.
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Plants polysaccharides and their importance in food production
Klanicová, Barbora ; Illková, Kateřina (referee) ; Omelková, Jiřina (advisor)
Some findings about plant polysaccharides, their characteristics and structures, modifications, changes, their biosynthases, isolationes and primarily their importance in food-stuff industry are the subject matter of this review. Because of their modifications and because of the significant role they play in food-processing industry it is focused on starch and cellulose. For better understanding of whole meaning it was necessary to attend to the theme from the initiation – mainly the cell structure and then syntheses, especially photosynthesis, ways that are monosaccharides and polysaccharides generated.
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Processing optimalization of biodegradable starch based packaging and its characterization for adaptation on production technology
Krahulová, Veronika ; Ondreáš, František (referee) ; Lepcio, Petr (advisor)
This diploma thesis focuses on the problematics of preparation of biodegradable starch based packaging. The aim of the thesis is to optimize the preparation and verify the characteristics for further adaptation and production technologies. The films consisted of starch, PVA and glycerol. Four types of starches, three types of PVA and different ratios of glycerol were tested. Films were prepared by casting with glycerol as a plasticizer, instead of distilled water, to reduce the energy cost of the preparation. The mechanical properties of the films were tested as well. The experimentally determined values of elongation at break and tensile strength of the wheat starch films were compared with a semiempirical model. Results revealed that the preparation of thermoplasticization of starch with glycerol leads to a considerable increase in elongation at break but at the same time to a marked decrease in tensile strength compared to the preparation from solution. The rheological properties of the prepared films were also investigated. Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to study the structure of the films.
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Stanovení želatinizace škrobu zrna ječmene pomocí přístroje Rapid Visco Analyzer
Cetkovský, Tomáš
The gelatinisation temperature is one of the important parameters in the evaluation of barley quality. During gelatinisation, the viscosity of the mixture of starchy substance and solvent is being changed by temperature. The aim of this study was to measure the viscosity in the process of starch gelatinization of barley grain using Rapid Visco Analyzer (RVA). A total of 36 barley varieties were evaluated by RVA. Barley samples were analysed in the RVA, and 13minute and 15minute measurement methods were used to evaluate starch gelatinisation. The results were statistically evaluated and compared. The results of the measurements showed the validity of both methods, confirming their applicability in the malting and brewing industry. The maximum expanded measurement uncertainty for the parameters studied ranged from 1 to 16%. The parameters studied were 61.8–84.8% influenced by method and 2.6–30.6% influenced by variety, according to the analysis of variance and variance component estimation of RVA parameters. Gelatinization temperature was 84,8 % influenced by method and only 2.6% by variety. The gelatinisation temperature of the varieties was different depending on the type of method used. The RVA13 values averaged at 87.3 °C and in average were always 5.8 °C higher than those measured by RVA15. The average gelatinisation temperature measured by RVA13 was 81.5 °C.
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Determination of nutritional values and antioxidant capacity of different edible roots
Ciffrová, Karolína ; Bendová, Agáta (referee) ; Němcová, Andrea (advisor)
This bachelor thesis deals with selected edible roots, their nutritional composition, antioxidant capacity and use in healthy eating. Eight selected edible roots were analyzed: type A, B and C potatoes, red potatoes, sweet potatoes, and purple potatoes were selected as representatives of potatoes. Jerusalem artichoke and cassava represent the other two root crops. The theoretical section of the thesis describes the basic characteristics of root crops, as well as the description and composition of the nutritional substances they contain, i.e. proteins, carbohydrates, fats, vitamins and antioxidant properties. The general characteristics of the methods used for analysis are also described here. The experimental part is based on specific analyses, procedures, results, chemicals and laboratory equipment used to determine the basic nutritional values and antioxidant capacity of these selected root vegetables. First, the total dry matter content was established to be about 23 % in the selected root crops. Higher dry matter content was determined for the cassava at 35 %. Crude protein content determined by the Kjeldahl method ranges from 6.5-9.9 %. The gravimetrically determined fiber in the given root crops was in the range of 0.27–0.91 %. The starch content is significantly higher in the cassava (46 %) than in other root crops. The inulin content was determined in sweet potatoes and Jerusalem artichokes instead of starch content; this value is significant for the Jerusalem artichoke (258.58 g/kg). Fat content in grams per 100 grams of dry matter was determined by Soxhlet extraction. Significant fat content was determined for sweet potatoes (12.6 g/100 g). From the extracted fats, the fatty acid profile was determined for individual root vegetables, such as the content of saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Total and reducing carbohydrates, determined by the spectrophotometric method, were measured separately in the peel and pulp of the root crops. Antioxidant capacity was determined using antioxidant activity values, polyphenol and flavonoid concentrations. Of the vitamins, vitamin C was determined, vitamin E only in type B, C and purple potatoes. For sweet potatoes, beta-carotene was determined to be 540.56 g/g. The measured and calculated results are plotted in graphs. Finally, there is a discussion of the conclusions of the individual methods.
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The importance of variety in yield of table potatoes (\kur{Solanum tuberosum} L.)
ŠPLÍCHAL, Jonáš
In the theoretical part of the bachelor thesis, attention was paid to the description of the tuber potato, morphological characteristics of the potato, and the division of varieties according to the length of the growing season and according to the cooking type. In the following chapters, the growing principles and conditions of potato pro-duction, the content substances in potato tubers and the possibilities of their influ-ence by cultivation technology and breeding were defined. Equally important is the chapter devoted to the varietal variation of production and content parameters of potato tubers since the practical part of the bachelor thesis was devoted to this to-pic. For this purpose, a small-plot experiment was set up at the Lukavec site (620 m above sea level) with potato varieties Adéla, Antonia, and Rosara, and the yield parameters (total yield, proportion of tubers over 35 mm) and selected content cha-racteristics (starch and dry matter content) were monitored. The Rosara variety had the highest starch and dry matter content.
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