|
|
Influence of stabilizers and other components on final quality of mixtures for ice-cream production
Sládková, Veronika ; Obruča, Stanislav (referee) ; Márová, Ivana (advisor)
Presented diploma thesis was focused on study of influence of stabilizers and other components on final quality of mixtures for ice-cream production. This thesis was worked out in cooperation with Frujo Co., Ltd., Tvrdonice to find out the most suitable stabilizer with positive influence on the quality of final product. In experimental part six mixtures of stabilizers, three mixtures for ice-cream production and particular ingredients for production of mixtures for ice-cream production were analysed. Saccharides and lipids were analysed only in mixtures of stabilizers. Content of saccharides was analyzed using spectrophotometry and HPLC/RI. Lipid components were analysed by TLC. Viscosity was measured by rotatory viscosimeter and the differences of flow curves of each mixture with different stabilizers were monitored. Based on viscosity measurements some ice-creams with different stabilizers were chosen for sensory analysis. Mixture of stabilizers “Stobicol” was analysed for active compounds and antioxidant stability. Microbiological stability was tested in all of the stabilizers and also in particular ingredients including final mixture for ice-cream production. In three ice-cream mixtures of different flavour protein composition was measured by microfluidic electrophoresis. The highest content of total and reducing saccharides was determined in hydrolyzed samples. The highest values of total saccharides were found in mixture of stabilizers “Meyprogen”, the highest values of reducing saccharides were detected in stabilizer “Swissgum”. Content of triglycerides was found out almost in all of the measured mixtures of stabilizers using TLC method even though according to formulas provided by producers there should not be any. Diglycerides were detected in “Meyprogen” too even though this mixture of stabilizers should contain only saccharides. Based on results of rheology measurements and in connection with sensory analysis “Meyprogen” stabilizer could be recommended as the best material for the industrial production.
|
|
|
Properties of biocomposites based on flax fibers
Pelánová, Markéta ; Obruča, Stanislav (referee) ; Přikryl, Radek (advisor)
This thesis is focused on composites, which are composed of degradable components. The theoretical part deals with composite materials, treatment of fibers and properties of composites. The purpose of this study is to create a composite consisting of polyhydroxybutyrate, which is reinforced with flax fibers with various modifications. The thesis also evaluates the effect of reinforcing fibers in the composite material on the tensile properties and hydrolytic stability and degradability of the composite in compost in laboratory conditions.
|
|
|
Hydrolytic cleavage of coffee spent ground
Skřivanová, Veronika ; Hlaváček, Viliam (referee) ; Obruča, Stanislav (advisor)
The bachelor thesis deals with various types of hydrolysis of spent coffee ground for the following biotechnological applications such as the culture medium. The work included mechanical, acid, alkaline and enzymatic hydrolysis. The resulting hydrolysates were analyzed concerning the content of reducing carbohydrates, and potentially inhibitory substances polyphenolic nature. The results show that the best conditions for culturing yeast samples were prepared with a concentration of coffee 150 g/l hydrolysed combination of 2,5% mineral acid by heating at 121 °C for 15 minutes. Using ultrasonic homogenizer significantly increases the effect of hydrolysis. The enzymatic hydrolysis is best placed hydrolyzate prepared cellulase. The hydrolysed spent coffee grounds were used as the production medium for the production of ethanol by Saccharomyces cerevisiae. For samples was determined concentration change of glucose and ethanol by HPLC/RID. The highest concentration of biomass sample contained hydrolyzed cellulose on the other side, the highest yields of ethanol (20,07 g/l) were achieve using hydrolysate prepared by 2,5% hydrochloric acid.
|
|
|
Study of bioremediation of some organic polutants by Cupravidus necator
Miléřová, Miluše ; Hurtová, Jana (referee) ; Obruča, Stanislav (advisor)
The aim of this work is the study of bioremediation of p-nitrophenol using bacteria Cupriavidus necator. The theoretical part contains a summary of organic pollutants and the bioremediation aproaches used to remove them from the environment. In the experimental part of this work we used bacteria Cupriavidus necator H16 and its mutant strain Cupriavidus necator H16/PHB-4 unable of PHB accumulation. The experiments were performed with different concetrations of p-nitrophenol and also under none-optimal conditions. Apart from concentration of p-nitrophenol, viability of the bacterial cultures was determined by flow cytometry. During cultivation in progress for sub-optimal conditions with a concentration of 50 mg•l-1 p-nitrophenol at 4°C using a flow cytometer seemed more resistant bacteria Cupriavidus necator H16. On the contrary strain Cupriavidus necator H16/PHB-4 was more resistant at 37 °C. The biodegradation assay was also performed in fermentor, during 51 hours lasting cultivation, bacterial culture degraded 65 % of p-nitrophenol and moreover decreased wavelenght of maximum in absorption spectra from 401 m to 384 nm was observed. The quantity of PHB was analyzed by gas chromatography with FID detector along with the p-nitrophenol determined by spectrophotometry, whose maximum content of PHB was achieved in 20 hour of cultivation
|
|
|
Utilization of the polyelectrolyte complexes in medicine and cosmetics.
Karásková, Iva ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This thesis is focused on the possibilities of polyelectrolyte complexes of humic acid and chitosan. In the experimental part, based on a literature search, were optimized appropriate procedures for preparing such complexes in hydrogel form. The main aspects of the preparation, the effect was studied, the influence of the direction of the addition, the concentration, pH and ionic strength. Furthermore, the encapsulation method was tested to give chitosan pearls. Work was aimed for cosmetic and medical applications.
|
|
|
Microbial production of extracellular polymers and their involvement in stress response
Müllerová, Lucie ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
Bachelor’s thesis is focused on the production of extracellular polysaccharide pullulan by microorganism Aureobasidium pullulans, purification of pullulan and its possible use as a cryoprotectant. As a part of this work a description of A. pullulans, pullulan and an overview of involvement in its stress response were provided. In the experimental part growth characteristics of A. pullulans (the strain CCM 8182 was used) and pullulan production during growth in optimal conditions was analyzed. Biomass production was the highest with fructose as a carbon source (3,580 g/l CCM 8182), the highest pullulan production occurred when using sucrose as a carbon source (10,300 g/l F 148). Among three organic solvents used for pullulan precipitation – ethanol, acetone, isopropylalcohol, ethanol was selected as the best for further experiments in ratio 1:2 (fermentation broth:ethanol). Pullulan purity was characterized by HPLC. As a further part of this work, cryoprotectant properties of pullulan at temperatures – 72° C, -18° C, 4° C and 60°C were studied. The presence of pullulan at temperatures – 72° C and 60° C was found to be detrimental to cell viability. At temperatures – 18° C and 4° C the cryoptotectant activity of the polysaccharide was confirmed.
|
|
|
Encapsulation of some enzymes into organic particles
Hazuchová, Eva ; Obruča, Stanislav (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on encapsulation of some enzymes into organic particles. The theoretical part is aimed to enzymes, their general characteristics, structure, activity and use, and to encapsulation techniques. Some methods used for analysis of particles, namely the determination of the distribution of particle size using dynamic light scattering, and determining the stability of the particles by the zeta potential, are described too. The experimental part describes methods of preparing particles, methods of determining the encapsulation efficiency and methods for determining particle size and stability. During the experiment part four types of enzymes were encapsulated, partly by manual preparation and partly by encapsulator. Encapsulation efficiency, size and stability of prepared particles were determined too. The particles were exposed to artificial intestinal, gastric and bile juices, as well as the effect of model foods. Subsequently, their long-term stability was observed.
|
|
|
Utilization of waste from the food industry for wastewater treatment
Nedvědická, Lucie ; Obruča, Stanislav (referee) ; Diviš, Pavel (advisor)
This bachelor thesis disserts about options and issues how to utilize waste from the food industry for wastewater treatment contaminated with heavy metals. The theoretical part describes the general characteristics of heavy metals, as well as the permissible and limit values of these heavy metals in waste water. Furthermore, it is described in this document which chemical methods can be used in order to remove heavy metals from wastewater. This thesis also deals with methods how to analyze the adsorbed amount of sorbed substance, means by using AAS, AFS, AES, MS and ICP – OES methods. At the end of the theoretical part, the issues of the different wastes from the food industry are dealing with and their adsorption ability. In the experimental section it was investigated the tea waste utilization in order to eliminate copper ions from waste water. It has been tested mainly the effect of pH on the adsorption of copper onto tea waste and maximum possible adsorption capacity onto tea waste. The pH optimum for the sorption of cooper from solution onto tea waste was within range 5-6 and the maximum possible adsorption capacity 0,0336 mmol•g-1 was determined. The results indicate that the tea waste could be used as a suitable adsorbent for the purification of waste water, mainly due to good availability, low cost and good adsorption ability of heavy metals.
|
|
|
System of collagen-hyaluronan in colloidal silver
Sklenářová, Renáta ; Obruča, Stanislav (referee) ; Hurčíková, Andrea (advisor)
The bachelor thesis is focused on the characteristics of solutions of hyaluronan and collagen in colloidal silver. These solutions polysaccharide and protein were prepared at several concentration rows that were analyzed by densitometer from Anton Paar and rheometer from TA Instruments. There were measured density, ultrasonic velocity and viscosity. The aim was to find the optimal ratio of collagen and hyaluronan in colloidal silver, which would suit the transdermal absorption and prepare skin healing spray.
|
|
|
Enzymatic hydrolysis of wastes associated with coffee production
Kovářová, Markéta ; Skoumalová, Petra (referee) ; Obruča, Stanislav (advisor)
This bachelor thesis is focused on study of potential production of extracellular hydrolytic enzymes by microorganisms – bacterium and moulds, which have been cultivated on spent coffee grounds. The theoretical part deals with characterization of coffee and utilization of coffee by-products. There are also subscribed microorganisms and enzymes which have been noticed. In experimental part coffee ground was used as the sole substrate for production of extracellular hydrolytic enzymes. Productions of protease, cellulase, mannase and lipase enzymes were observed. None-identified isolate of mould spontaneously contaminating spent coffee grounds was identified as the best producer of these enzymes. Subsequently the conditions of cultivation such as water content and shaking vs. static cultivation of this moulds were optimized. Further, we performed partial purification and pre-concentration of the enzyme cocktail by ultrafiltration, ultradialysis and PAGE-SDS characterization of extracellular enzymes was performed as well.
|
guest ::
