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Monitoring of cereal products uptake in a sample of Czech population
Vlachová, Martina ; Hurtová, Jana (referee) ; Márová, Ivana (advisor)
This bachelor’s thesis was focused on monitoring of consumption of cereal products and analysis of some of their active components. In theoretical part an overwiev of cereals and their composition was introduced. In experimental part a set of analytical parameters was obtained in selected cereal products: total phenolics, total flavonoids and antioxidant activity. The highest level of these active substances was detected in products containing chocolate and forest fruit. Further, 161 completed consumer questionnaires were collected. From these data common knowledge in consumers, their shopping conventions and individual products preferences were evaluated.
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Influence of polysaccharides on caffein absorption from beverages
Osecká, Karolína ; Márová, Ivana (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis was focused on investigation of the interaction between the polysaccharide sodium hyaluronan (HA) and the alkaloid caffeine (CAF). The reason why this thesis was focused on study of aqueous solutions of hyaluronan with caffeine is that presence of polysaccharide can slow down the realising from hyalurona-caffeine complex. At first, it was determined whether the photophysical properties of caffeine reacts in different polarity solvents. Based on these results was studied the interaction of caffeine and hyaluronan using the fluorescence. Emission and excitation spectra of caffeine were observed. The HA of molecular weight of 1.7 MDa were chosen for the study of the interactions with the caffeine of concentration the caffeine contained in coffee. The results of interaction that would result to influence the emission properties of CAF, not show. In acidic solutions leading to the formation of various shapes of HA and by centrifugation it was determined whether HA in this form interacts with CAF, which was shown to decrease the absorbance of the supernatant in the CAF. The solution and the mixtures were measured in four types of environment in hydrochloric acid solutions at different pH. The influence of constant addition of caffeine and the HA of molecular weights of 1.7 MDa with different concentrations in different acidic solutions. As a part of the work was to determine how hyaluronan behaves in strongly acidic solution. And then determine the pH in model gastric juices after intake of Coca Cola and Kofola. The obtained results can be used as for description of the behavior of caffeine in the presence of selected polysaccharide.
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Antimicrobial peptides and their application into foods
Janhuba, Filip ; Petrik, Siniša (referee) ; Márová, Ivana (advisor)
The presented thesis is focused on a study of antimicrobial peptides and their potential applications into foods. Two types of antimicrobial peptides were studied in detail - bacteriocin nisin and antimicrobial enzyme lysozyme. In theoretical part an overview of antimicrobial peptides used in food industry was introduced. The experimental part of this work was focused on optimization of methods for the determination of antimicrobial peptides concentration. Commonly used spectrophotometric methods for quantitative analysis of total proteins as well as high performance liquid chromatography were tested. To determine the molecular weight and purity a modified SDS-PAGE with the addition of urea and tricine buffer was performed. Further, encapsulation of nisin into liposome was tested. Encapsulated particles were prepared by three different procedures: by ultrasonication, ethanol injection and TLE. Particles stability, distribution and size were studied by dynamic light scattering. Stability of encapsulated peptides in model conditions and model foods was studied too. Finally, antibacterial properties of the selected peptides using test system Bacillus subtilis were studied. Nisin already showed antimicrobial effect at low concentrations - about 1 µg/ml. The inhibitory effect of nisin was more evident in liquid cultures.
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Aggregation processes in amphiphil-polymer system
Šejnohová, Michaela ; Márová, Ivana (referee) ; Pekař, Miloslav (advisor)
This Bachelor´s thesis is focused on the exploration of polyelectrolyte-surfactant system by fluorescence spectroscopy with pyrene as fluorescent probe. Cationic cetyltrimethylammonium bromide (CTAB) was used as a surfactant. Native hyaluronan was used as polyelectrolyte. Hyaluronan was used in one constant molecular weight and one constant concentration. The whole system was prepared in an aqueous environment. Interactions were studied in area between critical aggregation concentration (CAC) and critical micelle concentration (CMC). The influences of the concentration of pyrene and the effect of the way of the samples preparation on aggregation behavior were also studied. It was found that above the critical aggregation concentration exists an area where stable properties of aggregates can be found. The concentration of pyrene has a major effect on the fluorescence properties of the system. Preparation of samples affects the aggregation of the system. At higher surfactant concentrations, above the stable area, was observed phase separation and gel formation.
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Alcohol-free beers with herbal extracts
Vyskočilová, Terezie ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
This bachelor thesis deals with alcohol-free beers and herbal extracts, which are the beers flavoured with. In the theoretical part the methods of non-alcoholic beer production and the representation of the active ingredients in herbs are described. A total of 7 herbal extracts were prepared and added into 3 non-alcoholic Czech beers. Each variant was examined in order to detect changes of the content of active substances before and after the addition of the herbal extract. The content of polyphenols, flavonoids, bitter substances and iso-bitter acids as well as antioxidant activity were analyzed spectrophotometrically. Using HPLC/UV-VIS analysis a content of catechins was assayed. The two selected flavours were encapsulated into liposome; the particles were tested of size and stability. Sensory analysis of all herbal extracts including the encapsulated ones was performed to determine the response of consumers and flavour preferences.
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Health effects of Czech beer
Bokrová, Jitka ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
The aim of this bachelor thesis was to study physiological effect of various kinds of lager beer and to compare these effects in Czech beer and several beers produced in foreign countries. In theoretical part Czech beer characteristics and biologically active compounds in beer are described. Quantification of total phenolics, total flavonoids, antioxidant activity and bitter substances was performed photometrically. The quantity of vitamin C was determined by high performance liquid chromatography with spectrophotometrical detection. Beer buffering capacity was analyzed by pH measurement in artificial stomach and intestinal liquid, respectively. Analysis of physiological effect was accomplished by analysis of proteolytic enzyme activity. The total of 22 samples (16 Czech and 6 foreign lager beers) was studied. In these samples levels of basic technological characteristics and buffering capacity were compared. Alcoholic and non-alcoholic beers were compared too. According to experimental data it was confirmed that consumption of Czech beer (mainly lager beer) positively influences digestion process and activity of digestive proteolytic enzymes.
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Encapsulation of caffeine
Patočková, Klára ; Pekař, Miloslav (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on possibilities of encapsulation caffeine in micro- and nanoparticles. In the theoretical part was devoted to information about caffeine, liposomes and polysaccharides and also on the techniques of encapsulation. In the experimental part 5 different methods were used for preparation of micro- and nanoparticles with encapsulated caffeine. Caffeine was packaged into liposomes and polysaccharide particles (chitosan/alginate). Encapsulation’s effectiveness was determined by HPLC/UV-VIS. Prepared particles were monitored for size and stability by dynamic light scattering. The particles were exposed to the arteficial stomach and intestinal juices and bile acids. Particle stability and amount of released caffeine was monitored. Analytical centrifugation was used to measurement of sedimentation velocity and stability of the prepared particles. Caffeine containing particles were added in several soft drinks to determine particles amount when turbidity occurred.
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Production of mcl-PHA by selected bacteria
Eremka, Libor ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
The aim of this work is to study the possibility of microbial production of polyhydroxyalkanoates with medium chain length (mcl-PHA). For production two bacterial strains were used: Pseudomonas putida and Pseudomonas aeruginosa. Theoretical part of bachelor thesis deals with the biosynthesis of polyhydroxyalkanoates, their material properties and microbial producers. In experimental part selected bacteria were cultivated on different substrates to evaluate their ability to utilize various carbon sources and accumulate mcl-PHA. Content and composition of mcl-PHA accumulated in biomass were analyzed by gas chromatography with FID. Pseudomonas putida produced more mcl-PHA in medium containing canola oil as sole carbon source when compared with Pseudomonas aeruginosa. P. putida produced 2,11% mcl-PHA in medium containing glycerol as carbon source.
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Characterization of waste rice substrates and their potential utilization by microorganisms
Kapar, Jiří ; Duroňová, Kateřina (referee) ; Márová, Ivana (advisor)
The aim of this bachelor thesis was to characterize some cereal substrates. Based on the results of group parameters the most suitable substrate for cultivation of model industrial microorganisms was proposed. Analysis of total phenolics, reducing sugars and total sugars was performed spectrophotometrically. Using high-performance liquid chromatography with refractometry index detection content of individual mono-and disaccharides was measured. Saccharides were extracted from cereal substrates by water and then acid hydrolysis was applied. Two rice substrates were then used as nutrition sources for cultivation of two model industrial microorganisms: yeast Rhodotorula glutinis and bacterium Bacillus subtilis. Before use to production media substrates were processed by chemical and enzyme hydrolysis and analyzed. Production of microbial biomass in media with modified waste substrates was evaluated.
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Potential use of waste lipid substrates and glycerol to production of carotenoids by yeasts
Kostovová, Iveta ; Obruča, Stanislav (referee) ; Márová, Ivana (advisor)
The aim of this study was use of lipid waste substrates and waste glycerol as carbon sources for red yeasts. Six yeast strains, namely Rhodotorula glutinis, Rhodotorula rubra, Rhodotorula aurantiaca, Cystofilobasidium capitatum, Sporobolomyces roseus and Sporobolomyces shibatanus were used for cultivation. All studied yeast strains were able to utilize glycerol and rapeseed oil as a carbon source. Cultivation in oil medium was in most of strains accompanied by decreased production of carotenoids. Increased production of ergosterol, lycopene and biomass was observed in some strains only. Most of yeast strains cultivated in glycerol medium produced increased amount of biomass as well as carotenoids. The best producer of bi-omass and pigments was yeast strain Sporobolomyces roseus CCY 19-6-4 grown in medium containing glucose and glycerol in a 1:1 ratio.
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