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The assessment of basic chemical parameters of natural cheese
Školová, Dominika ; Babák, Libor (referee) ; Vítová, Eva (advisor)
The aim of this work was to determine basic chemical parameters of natural cheese, namely Camembert type (white mold cheese) and Emmentaler type (cheese with high-heat curd). Model samples of cheese were produced in a pilot plant using unpasteurized milk in"organic" quality. Based on the literature search following parameters suitable for simple and fast characterization of cheese composition were selected: dry matter (drying to constant weight), fat in dry matter (calculated), total nitrogen (resp. determination of protein content) by the Kjeldahl method and fats, resp. total lipids (extraction with solvent). The results were finally compared with samples of the corresponding cheese type purchased on the market.
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The Study of Biopolymers Stability Using Light Scattering Techniques
Kratochvíl, Zdeněk ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
The stability of chosen biopolymers (or simple carbohydrates and amino acids) was in-vestigated using light scattering methods. Samples were prepared by dissolving the sub-stance in deionised water or in diluted acetic acid. Firstly, the effect of increasing concen-tration on zeta potential was observed and the optimal concentration for the next measure-ments was determined. Afterwards, the stability and the molecular weight of used sub-stances were studied during long-time storage in different time intervals. It was found out that chitosan, CMC, hyaluronate and sodium alginate were subjected to degradation whereas increase of the molecular weight and the zeta potential was observed in case of BSA. In the end, the samples were exposed to several different external effects, namely the influence of different temperatures, UV radiation and increasing ionic strength. The results showed that rather higher temperature has a significant impact on biopolymers stability. However, used biopolymers were hardly affected by UV radiation except BSA whose molecular weight increased considerably. Decrease of the zeta potential absolute values and the molecular size usually occurred with increasing ionic strength. The change of molecular weight was not detected.
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Fortification of bakery products with protein isolate from wheat bran
Bidmonová, Karolína ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
Proteins, as the major structural component of all cells and tissues, along with fats and carbohydrates, are a key macronutrient in human nutrition. An insufficient protein intake in the diet can lead to health problems and increasing protein malnutrition. Food fortification plays an important role in eliminating this protein deficiency. Wheat products, as a widely consumed food, seem to be a suitable commodity for protein fortification. Wheat bran was selected as a suitable source of protein due to its availability, protein content and relative simply method of a protein isolation. In the experimental part, the protein was extracted from wheat bran and used to prepare the mixtures. The mixture contained T530 flour and the 5%, 10% and 15% addition of the wheat bran protein isolate. From these mixtures, doughs were prepared and were subjected to chemical and rheological analysis. Finally, wheat baguettes with the addition of wheat bran protein isolate were made. The texture and taste properties of the baked products were verified by sensory analysis. The mixtures of flour and whey protein and a sample of unriched flour were also analysed to compare the results. Applied tests have shown that the addition of protein influences not only nutritional and chemical but also rheological properties. The addition of wheat bran protein isolate had a negative impact on the taste properties of the baguette Higher addition of BPI caused the increase of the bitterness of products. Taste optimization could be a topic for future study.
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Isolation of pure aminoacids from wheat bran
Sloupová, Klára ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
Wheat bran is a promising material containing a wide range of useful components, including proteins. In addition, it is produced in significant volumes. Currently, wheat bran is used for the production of energy by combustion and for feed purposes. Gradually, new methods of valorization of this material are being sought. One of the possibilities of using wheat bran is the isolation of proteins, hydrolysis, and separation of selected amino acids. This diploma thesis deals with this issue, it is focused on the recovery of arginine and leucine from a protein isolate. Proteins were extracted from wheat bran by changing the pH. Thanks to the subsequent lyophilization a protein isolate was gained. Prior to hydrolysis of the resulting isolate, a stability test of arginine and leucine amino acid standards was first performed, to which various hydrolysis methods were applied. Acid hydrolysis using a mineralizer, which was applied to the protein isolate, was proved to be the most effective. This was followed by the derivatization of the hydrolysates with OPA and analysis of the resulting hydrolysates by high-performance liquid chromatography with UV-VIS detection. Then, suitable adsorption and desorption conditions were optimized. It was found that the time dependence does not affect the amount of adsorbed material on the sorbent. Therefore, an application time of 15 minutes was chosen. While optimizing the amount of used standard, it was found that the optimal weight was 0.25 g of sorbent. The selected conditions were applied to the protein hydrolyzate. Two fractions were obtained by the separation of selected amino acids due to the change in the pH of the citrate buffer. After the application of this procedure, 0.26 g of arginine and 0.82 g of leucine were obtained from one kilogram after evaporation. From evaporation two, 1.01 g of arginine and 0.25 g of leucine were obtained after evaporation.
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Analysis of Protein Structure Visualisation Tools
Klemšová, Jarmila ; Jaša, Petr (referee) ; Burgetová, Ivana (advisor)
In this thesis we analyze several tools for protein structure visualisation. We describe the structure of the proteins, the databases for storing protein structures and their data formats. Next part of the thesis, provides detailed information about selected visualisation tools and some scripts for them. The thesis also include an example of visualisation of the selected protein.
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Detection of Homologous Enzymes
Gajdoš, Pavel ; Burgetová, Ivana (referee) ; Martínek, Tomáš (advisor)
Tato práce se zabývá vyhledáváním homologních enzymů v proteinových databázích, jejímž cílem je navrhnout nástroj poskytující takové vyhledávání. Čtenář se seznámí se základní teorií týkající se proteinů, enzymů, homologie, ale také s existujícími nástroji pro vyhledávání homologních proteinů a enzymů. Dále je popsáno ohodnocení nalezených existujících nástrojů pro vyhledávání homologních enzymů. Pro potřeby vyhodnocení byla vytvořena datová sada spolu s algoritmem pro vyhodnocení vyýsledků jednotlivých nástrojů. Další částí práce je návrh a implementace nové metody pro vyhledávání homologních enzymů společně s jejím vyhodnocením. Jsou popsány dva algoritmy (One-by-One a MSA) pro vyhledávání homologních enzymů, jejichž porovnání ukazuje, že MSA algoritmus je zanedbatelně lepší z hlediska přesnosti než One-by-One algoritmus zatímco z hlediska rychlosti vítězí One-by-One algoritmus.
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Effect of the dry hopping of the stability of beer foam
Benda, David ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the influence of dry hopping on the stability of the beer foam. It was observed how this effect affected general characteristics of beer, the content of hop bitter acids, proteins, phenolic compounds, selected micro- and macro elements, organic acids and the stability od the beer foam. Theoretical part characterises raw the materials for beer production, the substances affecting the stability of beer foam and the beer brewing process. Furthermore the beer foam is described froam a physical point of view together with the steps of its formation and drainage as well as other phenomena that lead to its disappearance. A detailed description of used analytical methods is included. The experimental part illustrates the preparation of the model beer and the implementation of dry hopping with the Czech hop variety called Kazbek. Dry hopping was carried out on day 3, day 5 and day 10 with a 3 g/l and a 6 g/l hop dose. The prepared beer was subsequently analysed for general characteristics, the beer foam stability, bitter hop acids, phenolic compounds, protein, selected micro- and macroelements and organic acids. Based on the measured data, there were found correlations between the observed beer parameter and the stablity of the beer foam. The results revealed that dry hopping in beer increases the content of the phenolic compounds and bitter substances, but its effect on the beer foam stability is negative.
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Utilization of micropreparative isoelectric focusing in the analysis of biological samples
Vlčková, Zuzana ; Flodrová, Dana (referee) ; Šalplachta, Jiří (advisor)
The aim of this Master Thesis is the optimization and verification of conditions of separation of proteins from biological materials. For the separation a developed technique called micropreparative isoelectric focusing is being used. The theoretical part describes analytical methods of biological materials with a focus on proteins which were used for the optimization of the developing system in general. This part of the Master Thesis also presents this method itself. Furthermore, basic characteristics of other techniques used to control the efficiency of the micropreparative isoelectric focusing are introduced. The experimental part depicts the individual steps of optimization of the micropreparative isoelectric focusing. The ideal separation procedure was firstly found out on the individual standard proteins, secondly on their mixture and lastly the optimised procedure was applied to a real biological sample. The efficiency of the micropreparative isoelectric focusing was verified by SDS-PAGE and MALDI-TOF mass spectrometry.
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Analysis of low-molecular proteins in barley by the SDS-PAGE method during malting
Myslivcová, Pavla ; Svoboda, Zdeněk (referee) ; Mikulíková, Renata (advisor)
This diploma thesis deals with the analysis of low molecular weight proteins in barley during malting by SDS-PAGE method. Attention was paid to PR proteins, specifically LTP proteins and thionins, considered to be connected with gushing effect. Barley samples, malt intermediates and malt samples taken in 10 consecutive days to cover the whole malting process were used for the experiment. In total, 5 samplings were used for the analysis. Proteins extracted from the samples were separated by SDS-PAGE using a Tris-tricine buffer system. The protein lines of LTP proteins and thionins were identified in the resulting gels. The relative optical density values of the selected protein bands were obtained to assess the effect of malting on these proteins. A similar pattern of change in the content of mentioned low molecular weight proteins during the malting process was observed. This was confirmed by finding a statistically significant positive correlation between the relative optical density values of LTP proteins and thionins. Furthermore, the relationship between the low molecular weight protein content and the gushing potential and the microbiological contamination of the samples was investigated, but was not confirmed.
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Prediction of Homolog Protein Sequences
Chlupová, Hana ; Bendl, Jaroslav (referee) ; Martínek, Tomáš (advisor)
Prediction and searching for homologous protein sequences is one of important tasks which are currently being addressed in the area of bioinformatics. According to the determination of homologous sequences of unknown protein sequence it is often possible to determine its structure and function in the organism. For searching homologous sequences, the most frequently used tools are based on direct sequence comparison, profile comparison or on the use of hidden Markov models. There is no universal method better than all others. To satisfy user`s request on needed sequence identity between domains and error rate between founded true positive and false positive pairs, the selection of proper method and its settings is needed. This work is focused to create tool which will help user to choose the best method and its settings according to his requirements. It was created on the basis of the analysis of method results with different settings. In addition, the implemented application offers the possibility to run this method and show its results.
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