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Identification and characterisation of selected properties of some strains of lactic acid bacteria
Sásková, Denisa ; Horák, Daniel (referee) ; Rittich, Bohuslav (advisor)
Nanotechnology is currently one of the fastest growing scientific disciplines. An interesting area of research is the biosynthesis of metal nanoparticles using microorganisms including lactic acid bacteria. In the first part this diploma thesis focuses on verification of identity of bacterial species Lactobacillus casei and Lactobacillus paracasei by genus- and species-specific PCR. In the next part of experimental work the capability of six Lactobacillus strains to produce silver nanoparticles is tested. Synthesis of nanoparticles was confirmed for all the strains depending on the amount of added AgNO3 and on time of cultivation. Differences between the strains were detected.
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Molecular identification of selected species of lactic acid bacteria and bifidobacteria in food additives
Riegelová, Kristýna ; Rittich, Bohuslav (referee) ; Španová, Alena (advisor)
Probiotic lactic acid bacteria and bifidobacteria are natural part of microflora of gastrointestinal tract. In the present, day they are grossly exploited in food processing industry. The aim of the work was molecular identification of bacteria of genus Lactobacillus and Bifidobacterium in complex matrices of two food additives. Total DNA was isolated from crude cell lysates by magnetic particles P(HEMA-co-GMA). Isolated DNA was amplified in genus-specific and species-specific PCRs. Amplicons were detected by agarose gel electrophoresis. Results were compared with declared specification given by producers in three different batches.
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Identification of probiotic species of genus Lactobacillus
Vystavělová, Růžena ; Trachtová, Štěpánka (referee) ; Rittich, Bohuslav (advisor)
Germs of the Lactobacillus genus form part of the micro flora, the composition of which exercises the influence on the state of health of its host. In view of the fact that at some types of Lactobacillus there were proved clinical effects (e. g. strengthening of the immune system, prevention of diarrheic illnesses and so on), the Lactobacilli have been often used for making fermented dairy products and they form part of food additives because of their probiotic effect. Germs of the Lactobacillus genus and germs of different types of Lactobacillus can be identified by means of PCR based on amplifying specific DNA fragments. The complete bacillary DNA Lactobacillus rhamnosus was separated by the phenolic extraction method. The presence of germs of the Lactobacillus genus was proved by the generic-specific PCR method; the presence of Lactobacillus rhamnosus germs was proved by the species-specific PCR method.
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Probiotic lactic acid bacteria in food products
Sásková, Denisa ; Rittich, Bohuslav (referee) ; Španová, Alena (advisor)
In food industry molecular genetic methods based on DNA analysis are used for identification of probiotic microorganisms. An example of these methods is the polymerase chain reaction, in which specific fragments of DNA are amplified using short oligonucleotide primers. The teoretical part of this bachelor thesis follows probiotic bacteria, their features, beneficial health effects and use in food and clinical applications. The experimental part of the thesis focuses on an analysis of two probiotic dietary supplements. DNA was isolated from these products by method of phenol extraction. The use of PCR confirmed the presence of DNA of probiotic bacteria of genera Lactobacillus and Bifidobacterium.
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Study of aerobic cultivation conditions with select strain of Lactobacillus
Šupinová, Petra ; Burdychová, Radka (referee) ; Babák, Libor (advisor)
The aim of this study was focused on the study of conditions of growth of strains Lbc. paracasei subsp. paracasei CCDM 211, Lbc. paracasei CCDM 212, Lbc. paracasei subsp. paracasei CCDM 213 and Lbc. salivarius CCDM 216 in media with different amount of carbon-source (glucose, lactose and whey). Next part of the experiment was dealed with study of conditions of bacteria growth at stress conditions (lower pH). The purity od bacterial culture was verified with help of streaking. Purity DNA isolated from bacteria was tested using agarose gel electrophoresis, DNA concentration was estimated spectrophotometricaly. The presence of bacteria of genus Lactobacillus was proved using polymerase chain reaction (PCR) with genus specific primers.
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Identification of lactic acid bacteria in food products using amplification methods
Jurečková, Nela ; Trachtová, Štěpánka (referee) ; Španová, Alena (advisor)
The aim of the study was isolation of genomic DNA from 7 milk products (yogurts/ yogurt milk) in quality for use it in PCR. Magnetic microparticles (P(HEMA-co¬-GMA)) were used for the DNA isolation. DNA was reversibly adsorbed to the microspheres in the presence of 8% poly(ethylene glycol) PEG 6000 and 5 M sodium chloride. The adsorbed DNA was released from the microspheres in a low ionic strength TE buffer and use as DNA matrix in genus specific PCR Lactobacillus. The presence of DNA of genus Lactobacillus was detected in all analysed products.
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Identification of selected species of lactic acid bacteria in dairy products
Vystavělová, Růžena ; Trachtová, Štěpánka (referee) ; Rittich, Bohuslav (advisor)
Lactic acid bacteria are natural part of the human gastrointestinal tract. They are often used in food supplements and for the production of fermented dairy products. This thesis focuses on the identification of selected species of lactic acid bacteria and bifidobacteria in cheese and dairy products. Bacterial DNA was isolated by magnetic particles P(HEMA-co-GMA) from crude cell lysates from 9 products. Isolated DNA was amplified in genus-specific and species-specific polymerase chain reactions (PCR). The obtained amplicons were detected by agarose gel electrophoresis. The results of PCR were compared with those provided by the manufacturers and there has been declared a match.
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Study of yogurt composition in process of its preparation
Fajtl, Zbyněk ; Vítová, Eva (referee) ; Veselá, Mária (advisor)
This thesis deals with the study of yogurt preparation and changes during its storage. The theoretical part contains information about parameters affecting both the preparation and properties of the final product. The experimental part describes methods and procedures used for determination of critical parameters such as lactic acid, lactose, glucose and galactose concentrations (HPLC-RI), amounts of streptococci and lactobacilli. The data was graphically evaluated and commented on. The work also included sensory analysis in which the prepared yogurt was compared with commercially available products. The results of this work can serve both consumers and smaller yogurt producers.
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Technologie výroby a hodnocení jakostních parametrů bílých sýrů v solném nálevu
Mištová, Dominika
This thesis deals with the production technology and quality parameters evaluation of white brined cheeses. The characteristics, origins, technological procedures of production, and differences between them are described. The work aimed to carry out sensory evaluation and determination of physicochemical parameters. These criteria were identified for selected representatives of white brined cheeses available on the Czech market and for own samples produced under semi-operating conditions. A sub-objective was to compare both individual samples with each other and commercially available samples with the data given on the manufacturer's packaging. When comparing the results of the analysis with the data indicated on the package, the protein and fat content in both cases of commercially available samples was higher than declared by the manufacturer. On the other hand, the course of souring in the produced cheeses was insufficient. The titration results of the produced cheese samples differed by almost half from the cheeses purchased on the domestic market.
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Hodnocení mikrobiologických rizik jedlého hmyzu
Hedvičáková, Adéla
Eating edible insects is an activity that has recently become increasingly important. In order to use edible insects safely, it is necessary to carry out, among other things, an assessment of the risks associated with consumption. This work focused on the microbiological risk assessment of edible insects. The theoretical part of the thesis provides information on the nutritional properties of edible insects and the risks associated with insect consumption. It also mentions legislation related to the inclusion of insects in food. The thesis describes the impact of insects and their consumption on the environment and presents factors that need to be further addressed in the future. The thesis provides a list of important pathogenic microorganisms. In the practical part it is possible to find a statistical evaluation of the measured values of the pathogens present in the insects and in the feed. Total counts of microorganisms, Escherichia coli, Enterobacteriaceae, moulds, Staphylococcus aureus and lactic acid bacteria were determined. The results were compared with those of studies on similar topics.
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