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Production of biogenic amines in double moulded cheese
Šuláková, Miroslava ; Standara, Stanislav (referee) ; Veselá, Mária (advisor)
For production of double moulded chesses are used lactic acid bacteria, which can be present in a form of non-starter lactic acid bacteria or as starter or adjunct culture. Genera Lactobacillus spp. and Enterococcus spp. are prevalent microorganisms present in these cultures. Of course, these microorganisms are for us interesting because of their possibility of coagulation, proteolytic possibility, probiotic function and antibiotic resistance, but especially because of their decarboxylation abilities. Bacteria contain decarboxylation enzymes, which are able to decarboxylized free amino acid, which rising at proteolysis during process of manufacturing and cheese ripening. Biogenic amines are the result of proteolytic activity. Biogenic amines occur practically in all foodstuffs as a common product of metabolic processes. BA are mainly presented in fermented food (cheeses), where rice just microbial action. Typical representatives of biogenic amines, which occurs in double moulded cheeses (Sedlčanský Vltavín, Bresse bleu) and in blue cheeses (Bleu des Causses, Bleu d'Auvergne) are cadaverine, putrescine, tyramine a 2 fenylethylamine and in much smaller amount histamine, spermidine and spermine too. On assessment concentration of BA is used high pressure liquid chromatography with reverse phase (RP HPLC) with utilizing simple direct derivatization with dansyl chloride and detection by UV VIS detector.
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Kinetic of lactic acid formation in kefir
Fajtl, Zbyněk ; Vítová, Eva (referee) ; Veselá, Mária (advisor)
This bachelor thesis deals with the kinetic production of lactic acid and consumption of lactose in the kefir fermentation from one type of milk under the same conditions. The theoretical part contains information on kefir and kefir grains, lactose intolerance, antimicrobial properties and high-performance liquid chromatography. The experimental part describes the methods and procedures used in the manufacture of kefir itself, the determination of lactic acid and lactose. Kefir samples were tested at precise time intervals for lactose, lactic acid and lactobacilli. The data was graphically evaluated and commented. The results of this work may be beneficial for consumers with lactose maldigestion and for consumers searching for qualite source of lactobacilli for enhancing their gut microflora.
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Factors affecting stability and consumer acceptance of sauerkraut water
Vašků, Barbora ; Mikulíková, Renata (referee) ; Márová, Ivana (advisor)
This diploma thesis is focused on the optimization of pasteurization of the cabbage juice in order to extend its shelf life. The theoretical part is focused on the description of the sauerkraut production technology and characterization of the main components of fermented cabbage and its juice, it also deals with pasteurization options and presence of probiotic strains. In the experimental part, the composition of the brine was analyzed from a chemical point of view (bioactive substances, sugars, carbohydrates), from a microbiological point of view (presence of probiotics, pathogenic organisms) and the effect of selected pasteurization processes on these components. Pasteurization at 90 °C for 0.5 minutes was determined as the most suitable treatment, during which potential pathogens are being eliminated, while most of the original bioactive components are preserved. After suggesting the effective pasteurization treatment, suitable species of genus Lactobacillus was selected to enrich the cabbage juice product because of decreasing of probiotics viability during pasteurization treatment. The strain Lactobacillus plantarum was determined as the most suitable probiotic species for cabbage juice enrichment, due its ability to survive in 2 weeks storage at 8 °C in cabbage juice. Chemical composition after 2 weeks of incubation with mentioned organism has changed. Quantity of lactic and acetic acid increased, while no changes in content of vitamin C were observed. Finally, sensory analysis was performed to evaluate suggested mixed fruit-vegetable drink. According to results of sensory analysis, the drink composed of cabbage juice and apple-beetroot juice in the ratio of 2:1 was found as the most acceptable.
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The monitoring of the lactic acid bacteria in the Moravian wines
Valicová, Markéta ; Španová, Alena (referee) ; Omelková, Jiřina (advisor)
The aim of this Master Degree Thesis was to monitor the total number of lactic acid bacteria occurring in grape must during wine production. The study was performed on the red wine grape variety Cabernet Moravia from organic vineyard and on the white wine grape variety Sauvignon from both organic and integrated vineyards. The isolation of pure cultures of lactic acid bacteria from mixed cultures and subsequently their identification by genus and species-specific PCR was also subject of the thesis. The experimental results show that the number of viable cells of lactic acid bacteria is influenced not only by the wine grape variety, whether it is a variety of red or white wine grape, but also by the way of wine growing. The method of wine growing also had an impact on the species representation of lactic acid bacteria in each variety.
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Biological synthesis of silver nanoparticles
Kubínová, Martina ; Španová, Alena (referee) ; Rittich, Bohuslav (advisor)
Silver nanoparticles and its potencial use and influence on the environment is still object of research. Methodics of synthesis of silver nanoparticles is already well investigated and study deals with more economical ways of syntesis by metireals, which are environmentally friendly and nontoxic. Biochemical production of nanoparticles has both advantages. This study focused on the production of nanoparticles by lactic acid bacteria and antibacterial activity. Experimental part of the study focused on amplification DNA isolated from Lactobacillus gasseri K7, which has efficiency to form silver nanoparticles. DNA was isolated in PCR, it was confirmed using primers specific for domena Bacteria and species Lactobacillus gasseri.
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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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