National Repository of Grey Literature 123 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Use of yeasts of the genus Metschnikowia for the lipid production
Švitková, Bibiána ; Márová, Ivana (referee) ; Němcová, Andrea (advisor)
The oleaginous yeasts have an ability to accumulate an increased number of lipids, under certain circumstances. These microbial lipids differentiate in the number of fat acids present, which enables their wide application in biotechnological industry. This master’s thesis is aimed on lipid production, number of the fat acid groups present, and squalene production by Metschnikowia yeasts, based on the cultivating conditions. Biomass and lipid production was observed in separate cultivation media, with the addition of the different waste substrates. Production properties were observed by method of the gas chromatography. For the squalene production observation, a HLPC method was chosen. All production groups were able to accumulate lipids on the waste substrate, although in different values. These values were very individual, especially in the areas of the specific groups and growth on the given substrate. The lipid composition was different, which was caused by differences in the waste substrates. With regards to the squalene production – the yeasts from the Metschnikowia family were not able to produce squalene in the presence of the terbinafine and its increasing concentration. Therefore, the same procedure was chosen, as it was for the Yarrowia lipolytica yeast, with the difference in the sterol synthesis, however squalene was still not produced this way.
Determination of physico-chemical stability of toothpastes
Posztósová, Gyöngyi ; Vítová, Eva (referee) ; Němcová, Andrea (advisor)
This diploma thesis is focused on determining the physico-chemical stability of toothpastes. It is divided into theoretical and practical part. The theoretical part of the work deals with toothpastes, their short history and composition. Stability studies and methods of stability analysis are described below. In the practical part were performed long-term and accelerated stability studies on anhydrous toothpastes, on water-based toothpastes and on toothpastes based on sodium bicarbonate. The physical stability of the products was evaluated by monitoring the appearance and color visually and odor sensory, the pH value using a pH meter and the viscosity with a rotational viscometer. Chemical stability was monitored by determining the free fluorine content by ion chromatography and by ion-selective electrode, total phosphates and potassium also by ion chromatography, sodium bicarbonate by titration, soluble zinc by atomic absorption spectrometry and water activity was also monitored.
Influence of various cosmetic polysaccharides as prebiotics on skin microbiome
Pelánová, Lenka ; Brázda, Václav (referee) ; Němcová, Andrea (advisor)
The presented master thesis deals with the monitoring of the influence of polysaccharides which are used as an additive in the cosmetic products, on the monitored types of bacteria which are part of the skin microbiome. And it also deals with the study the effect of polysaccharides as prebiotics on selected species of bacteria that are part of the skin microbiome. Two polysaccharides were selected to determine the effects on the skin microbiome: Nanomoist and PoLevan S. The first part of the thesis focuses on the literature search which deals with skin anatomy, skin diseases and skin microbiome and its function. The experimental part is focused on monitoring changes in the quantity of selected microorganisms of the skin microbiome, before and after application of polysaccharides to the skin using qPCR. Staphylococcus epidermidis, Cutibacterium acnes, Escherichia coli and Micrococcus luteus were monitored. The PCR products were detected by agarose gel electrophoresis. The bacterium Staphylococcus epidermidis was detected on the skin to the greatest extent, especially after the application of the polysaccharides Nanomoist and PoLevan S. Thus, a positive effect of both polysaccharides on the growth of this bacterium was found.
Complex processing of technical hemp and application of isolated fractions
Kohútová, Darina ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
Hemp is a plant containing many active substances and it is widely used in industry. The most common applications are the food, pharmaceutical, textile and cosmetics industries. This diploma thesis dealt with the characterization of hemp fractions, which are created during hemp processing and their potential applications. The theoretical part was focused on the description of the plant, its chemical composition and the research of the active substances in hemp. Also, its industrial use, the technique of hemp processing and the current applications of individual fractions were summarized. In the experimental part, hemp fractions were analysed in terms of nutrient content. Hemp extracts were prepared using three solvents - hexane, 70% ethanol and distilled water, which were compared based on the extraction yield of polyphenols, flavonoids, antioxidants, chlorophylls and cannabinoids. Antimicrobial effects were analysed in hexane and ethanol extracts. By-products of hemp processing were used in some screening application in biotechnology, cosmetics and nutrition. The results show that the extract with 70% ethanol had the highest content of active substances. From the hemp fractions, hemp trichomes and Fedora flowers had the highest content of active substances. Cannabis by-products have the potential to become valuable substrates for yeast cultivation. Face scrub containing hemp flour as an abrasive component had favourable results and was acceptable to consumers, as was the prepared hemp flour raw bar, which was evaluated to be comparable to commercially available hemp protein raw bars.
Preparation of natural food supplements for children's nutrition
Kubisová, Petra ; Němcová, Andrea (referee) ; Skoumalová, Petra (advisor)
The presented diploma thesis is focused on complex characterization of chosen superfoods and subsequent composition of supplement suitable for children´s nutrition. Different kinds of superfoods were chosen for analyses, such as: barley grass (Hordeum vulgare), wheat grass (Triticum aestivum), moringa (Moringa oleifera), matcha tea (Camellia sinensis), microalgae chlorella (Chlorella pyrenoidosa), spirulina (Arthrospira platensis), flax seeds (Linum usitatissimum) and sesame seeds (Sesamum indicum). The theoretical part is focused on children´s nutrition issue and the most common food allergies and intolerances. Also, children food products legislation and characterization of chosen samples are included in theoretical part. Main macronutrients, such as saccharides, lipids and proteins, were analysed in the very beginning of experimental part. Fibre, fructan and -glucan, which have a high impact on intestinal microbiome and whole process of digestion, were analysed as well. However, barley grass was the best evaluated sample by containing 205,5 mg/g of insoluble fibre; 152,57 mg/g of fructans and 18,76 mg/g of -glucans. Finally, for complex nutritional profile, also samples pigments were analysed. Spectrophotometry, HPLC chromatography, gas chromatography and other analytical techniques were performed for experiments.
Cocultivation of yeasts and microalgae to produce enriched biomass
Bradáčová, Lenka ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
The diploma thesis is focused on the influence of biological stress formed by co-cultivation of heterotrophic (yeasts) and autotrophic (microalgae and cyanobacteria) organisms on the production of enriched biomass. The monitored groups of substances include carotenoids (-carotene, lutein, lycopene, astaxanthin, torularhodin), chlorophylls A and B, ergosterol and ubiquinone. Further, production of lipids was analyzed in the terms of fatty acid profile and lipid content in biomass. In the first part of the work, the yeast biomass production was investigated using different nitrogen sources. Glycerol was used as a carbon source in all parts of the work. Subsequently, the co-cultivation of yeasts with microalgae and cyanobacteria took place in a multicultivator with gradual increase of selected macroelements – nitrogen, magnesium and phosphorus. The last part of the work was focused on the co-cultivation of yeasts and microalgae in a laboratory fermenter. The best effect on the production of total biomass was the increased magnesium content and high nitrogen content in the basic medium. The best concentrations of carotenoids were achieved due to the double nitrogen and phosphorus content together. Chlorophyll production was significantly lower compared to carotenoids.
Use of insect flour for food and feed purposes
Árendásová, Veronika ; Zemanová, Jana (referee) ; Němcová, Andrea (advisor)
Insect meal has excellent potential as food or feed. There is a need to provide enough food for the growing population, which is linked to the increasing demand for livestock production. Meat and fish have always been the staple of the human diet as a rich source of proteins and fats for human nutrition. Fish is a good source of animal protein and fat for humans, which forms the basis of the diet of a large number of people who generally live in coastal areas. The increasing demand for fish is associated with a growing interest in high-quality and affordable fish feed. Nowadays, the main ingredient in fish feed is fishmeal, and the price is constantly increasing. The sustainability of the aquaculture industry depends on finding a substitute for fishmeal with the same nutritional value and availability. Recently, there has been a growing interest in animal protein from insects for fish fattening. This thesis focused on analysing insect meal from mealworm larvae (Tenebrio molitor) and its use for food and feed purposes. The theoretical part describes the mealworm, the use of insect meal for human nutrition, and fish fattening. It also describes the requirements of fish for individual nutrients and the characterisation of insects for feeding purposes, focusing on the mealworm used as an alternative feed ingredient in fish. The individual major nutrients, namely protein, lipids, fatty acids, amino acids, fibre, chitin, and selected minerals, were determined in the experimental part. The experimental part was divided into two parts, and the first part was divided into two phases. The first phase was used to determine the nutritional components in two fractions of insect meal from Tenebrio molitor larvae. The first fraction contained the fine fraction, and the second fraction the coarse fraction of insect meal. In the second phase, the content of nutritionally significant components was only determined in the insect meal from dried larvae without fractionation. A fish feed was designed from the analyses results. In the second part, the effect of the addition of insect meal from Tenebrio molitor for food purposes was investigated; specifically, the sensory properties of muffins were monitored. From the results, it can be observed that the nutritional composition of the insect meal suggests the possibility of using the mealworm larvae as an ingredient in the fish diet. The insect meal contains a high proportion of valuable proteins and lipids necessary for fish farming and a low proportion of carbohydrates, which unlike humans, fish do not need in their diet. The sensory analysis results indicate that consumers are not prepared to eat foods with added insects.
Determination of antimicrobial and antioxidant activity of selected herbal extracts
Čaková, Adriana ; Němcová, Andrea (referee) ; Vítová, Eva (advisor)
Tetradenia spp. is herb naturally growing in Africa and is part of family called Lamiaceae. The herb is used in traditional medicine to cure malaria, angina or as treatment for tropical skin diseases. Maceration was chosen from number of extraction methods, to obtain bioactive compounds from this plant. Optimization was performed with aim to retrieve as much of bioactive compounds as possible. Optimal conditions chosen were: temperature 60 °C, extraction time 40 minutes, solvent 40% ethanol and solid-solvent ratio 1:5. In total 63 aromatic active compounds were found in optimal extract. Terpenes were the most abundant (88,60 %), from them oxygenated monoterpenes (55,65 %) and monoterpenes (29,52 %). Compounds with highest percentage quantity were camphor (51,76 %), cis--ocimene (8,17 %), 3-octyl acetate (7,71 %), trans--ocimene (6,76 %), -terpinene (4,93 %), o-cymene (3,81 %), terpinolene (1,33 %), limonene (1,33 %), camphene (1,19 %) and borneol (1,20 %). Further, total phenolic content was 0,31 ± 0,02 mgGAEml-1, which equals 1,52 ± 0,11 mgGAEg-1 of plant. Antioxidant activity was 417,56 ± 32,84 gTEACml-1 and percentage of radical scavenging activity ABTS•+ was 88,99 ± 7,00 %. Finally antimicrobial activity was determined against bacteria Bacillus cereus, Escherichia coli and yeast Candida glabrata. Against E. coli and C. glabrata there was no inhibition exhibited. Against B. cereus there was seen mild inhibition activity. The results confirm that Tetradenia spp. contain a number of interesting aroma active compounds, which shows antioxidant and antimicrobial activity. The herb has a good potential as natural source of nutritious and sensory active compounds to be used into various foods.
Study of the effect of cosmetics on the human skin microbiome using molecular techniques
Alexová, Adéla ; Kovalčík, Adriána (referee) ; Němcová, Andrea (advisor)
The theoretical part of the thesis is focused on the basic description of the physiology of the skin, human microbiome and a brief summary of where individual microorganisms occur. Furthermore, there is a list of analytical and microbiological methods that are used in this thesis. In the beginning, the practical part is focused on determination of antimicrobial effects of the chosen cosmetic products using microbial tests. Then, the inhibiton and microbial effect of the chosen cosmetic products on examined microorganisms has been measured using ELISA method. The second part of the thesis is focused on the isolation of bacterial DNA in quality that would be high enough to be used for amplification in PCR. There has been an optimalization of isolation of microbial DNA that was to be found on tested subjects’ skin. The presence of chosen microorganisms on skin before and after the usage of cosmetic products was measured using a PCR method. PCR products were then detected using gel electrophoresis. From the gathered data it is clear that the number of observed microorganisms has changed significantly after the application of cosmetic products.
Testing of biological effect of glucans on cell lines in vitro
Šimková, Eva ; Holub, Jiří (referee) ; Němcová, Andrea (advisor)
The aim of this bachelor thesis is isolation and testing of -glucans from selected strains of yeast. In the theoretical part, characterisation of -glucans, microbial production of -glucans by yeast, determination of polysaccharides, exopolysaccharides and in vitro testing are described. Yeast have a cell wall made up of -glucans and -glucans are known for their healing properties. In the experimental part of this work deals with characterization of selected biomass yeasts in different forms and comparison of their effects and the amount of -glucans in each form. Stains of Metschnikowia pulcherrima, Cystofilobasidium infirmominiatum and Rhodotorula kratochvilovae have been selected for this thesis. Subsequently, the thesis deals with the isolation and testing of isolated -glucans from a selected lyophilised strain of yeast Rhodotorula kratochvilovae. The selected strain was isolated in 2 ways. The first method of isolation that was more friendly to conformation of -glucans due to the effect of ultrasonic homogenization of cells. The second method of isolation was less friendly to -glucans, using acid and base to homogenise them. Analyses of both extraction methods confirmed the presence of isolated -glucans, however it was found that the recovery of both methods was relatively low and requires further optimisation of the procedure. Overall, the better extraction procedure was the second method. A sample of this extract was further tested on the HaCaT cell line. The results of the pilot tests confirmed the cytotoxicity of the extract obtained by us.

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