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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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Determination of beta-glucans and pentosans in raw materials for production of beer and in beer
Piškulová, Lenka ; Sachambula, Lenka (referee) ; Mikulíková, Renata (advisor)
The content of beta-glucans and arabinoxylans in barley grain, malt and wort was monitored. The varieties of barley were Pionier, Libuše, Manta, Tango, KWS Amadora, Kampa, KWS Irina, Francin, Odyssey, Overture, Vendela, Petrus, Laudis 550, Sunshine, Kangoo, Xanadu, Sebastian, Bojos and Malz. These varieties were grown on three different habitats (Uherský Ostroh, Věrovany and Vysoká u Příbramě). The content of beta-glucans and arabinoxylans was also analysed in five different types of beer. In brewing and malting industry the content of beta-glucans and arabinoxylans is mainly monitored because of their negative influence on decanting of wort and filtration of beer. These substances can contribute to turbidity and precipitation in beer and thus negatively effect the stability of beer. The content of beta-glucans in barley grain, malt, wort and beer was determined by FIA method and the content of arabinoxylans was determined in barley grain, wort and beer by Douglas method. The highest content of beta-glucans in barley grain was found in 14/19 varieties at Uherský Ostroh, where the amount of beta-glucan content was in the range of 3,65-5,60 %. The highest beta-glucan content in malt was found in 17/19 varieties at Vysoká u Příbramě, where the beta-glucan content was between 0,15-0,79 % and the highest content of beta-glucans in wort was found in 16/19 varieties also at Vysoká u Příbramě. There was the beta-content in the range of 22-184 mg/l. The results of content of arabinoxylans in barley grain and wort were more balanced. The highest content of arabinoxylans in barley grain was found in 10/19 varieties at Věrovany. The content of arabinoxylans at this habitat was in the range of 3,04-4,56 %. The highest content of arabinoxylans in wort was determined in 8/19 varieties at Uherský Ostroh. The content of arabinoxylans at this habitat was in the range of 542-1040 mg/l. The highest content of beta-glucans in samples of beer was determined in a sample of light lager (207 mg/l) and the highest content of arabinoxylans was found in a samle of wheat lager (1465 mg/l).
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Dependence of quality parameters of malt on the temperature of mashing at sweet wort preparation
Zlámalová, Petra ; Sachambula, Lenka (referee) ; Mikulíková, Renata (advisor)
The Masters thesis deals with dependence of quality parameters of malt on the temperature of mashing at sweet wort preparation. The theoretical part focuses on the technology of malt production including description of ingredients, production parts, some kinds of malt and the quality parameters. There is also described the technology of sweet wort preparation and the methods of determination of the malt quality parameters in the sweet wort there. The experimental part focuses on determination of malt extract, viscosity, haze, colour, time of starch cleavage, pH, degree of fermentation and beta-glucans content. Based on temperature dependence of parameters, the individual samples were compared and the effects of temperature were discussed. The biggest extract of light and caramel malts was explored at 70 °C, of coloured malt at 50 °C. The lowest viscosity of light and coloured malts was explored at 65 °C, of caramel malt at 50 °C. The lowest haze of wort was at 65 °C. Ideal colour of all malts was at all mashing temperatures. Ideal pH of all malts was explored at 70 °C. Ideal time of starch cleavage was explored at 70-85 °C. The biggest achievable degree of fermentation and the hugest increase of beta-glucans content were explored at 65 °C.
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Study of gliadin content in beer
Porubiaková, Otília ; Svoboda, Zdeněk (referee) ; Mikulíková, Renata (advisor)
Enzyme-linked immunosorbent assay was used for the determination of gliadin in beer. It is a fast and reliable method that is commonly used in the food industry. Celiac disease is an autoimmune disorder, also known as gluten intolerance. Gliadin, as a component of gluten, causes serious health problems to people with celiac disease. Celiac disease patients must follow a strict gluten – free diet. In this bachelor thesis, content of gliadin in twenty selected samples of Czech beer, obtained from retail stores was observed and evaluated. The samples were analyzed by a RIDASCREEN Gliadin Competitive was observed and evaluated. Results were evaluated with RIDA SOFT Win software. Detected gliadin contents in beer samples were compared with the standards for gluten- free products. Content of gliadin in the selected samples of beer varied from
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Study of the Selected Types of Sulphur Compounds in Beer and Brewing Materials
Mikulíková, Renata ; Ventura, Karel (referee) ; Ventura, Karel (referee) ; Čáslavský, Josef (referee) ; Márová, Ivana (advisor)
Much attention has been recently devoted to sensorially active substances affecting beer quality in the Czech Republic and worldwide. Among them, the heterocyclic and sulphur containing compounds play an important role, some of them with high sensorial activity even in extremely low concentrations. Trace amounts of these compounds, which can be frequently found in foods, participate in formation of their aroma and this effect can be generally evaluated as favorable However, in malt or beer it is true only to a limited extent and the presence of heterocyclic and sulphur containing compounds are in this respect assessed rather unfavorably. The aim of the present study was to provide a survey about of problems in the field of sulphur containing compounds in barley, malt and beer, to describe metabolic paths leading to their formation and to verify experimentally possibilities of their determination using modern analytical methods. Sulphur-containing amino acids are a natural part of barley, malt and beer and are precursors of the origin of volatile sulphur substances. The most frequently occurring sulphur amino acids, metionine, cysteine and homocysteine, were selected for analytical monitoring. The method of gas chromatography was used to determine sulphur-containing amino acids in barley, malt and beer. Prior to the analysis, sulphur-containing amino acids were derived and volatile N(O,S)-ethoxycarbonyl propyl esters were formed; they were subsequently analyzed using the gas chromatography with mass detector (GC/ MSD) and the gas chromatography with flame photo detector (GC/ FPD). Direct analysis of sulphur volatile substances is possible only rarely as they are found in the analyzed matrices (malt, beer) only in very low concentrations ( g/kg,l - ng/kg,l). Before the analysis, the analytes must be extracted from the matrix and concentrated. The modern analytical methods SPME (Solid Phase Micro Extraction), SPDE (Solid Phase Dynamic Extraction) and TDAS (Thermal Desorption Autosampler) were experimentally compared for the extraction and subsequent concentration of sulphur volatile substances. The method of gas chromatography with flame photo detector was used to determine sulphur volatile substances. Following volatile sulphur substances were monitored: dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide, carbon disulphide, ethyl sulphide, diethyl disulphide, methionol, 3-methylthiophen, ethyl thioacetate, 2-methyl-1-buthanthiol. Only metionine was detected in significant amounts in the barley samples analyzed. Not only content but also dependence on a variety and locality were studied. Further, changes in methionine, cysteine and PDMS content during malting were followed. Results proved a significant decline in these substances content depending on the kilning temperature. Three types of fibers were tested for the analyses of the selected volatile sulphur substances in beer in the SPME method. PEG - a fiber with stationary phase Carbowax, PDMS - a fiber with stationary phase polydimethylsiloxan and a combined fiber CAR/PDMS - Carboxen and polydimethylsiloxan. Carbon disulphide, methionol, dimethyl sulphide, 3-methylthiophen and diethyl disulphide were detected with this method. Content of the other analyzed volatile sulphur substances was below the limit of detection. Further was tested usage the SPDE and TDAS methods. Both methods appear to be the suitable for the determination of volatile sulphur substances in beer.
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Determination of residues of the selected pesticide effective substances in wine using the GC/MS method
Ehrenbergerová, Martina ; Benešová, Karolína (referee) ; Mikulíková, Renata (advisor)
The grape is one of the oldest cultivated plants. It can be consumed as a fruit or it can be used as a raw material for making stews, juices or the cultivated drink – wine. Generations of wine-makers have been striving to improve both the cultivating conditions of vineyards and the quality of wine. Many harmful elements, such as herbivorous pests, diseases and storms are important factors that can have a negative impact on crop quality. To regulate the effects of these factors, an integrated protection system is used, incorporating agronomical measures, resistant varieties and a wide spectrum of pesticides. However, increasing the usage of pesticides brings certain dangers to both the production quality and the environment. This necessitates the monitoring of the negative effects, including the content of pesticide residues in the grapes. My thesis studies and experimentally assesses selected pesticide residues in certain wine samples.
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Optimalization of SPME for assessment of volatile sulphur compounds in malt and beer
Mišovie, Zuzana ; Vespalcová, Milena (referee) ; Mikulíková, Renata (advisor)
Volatile sulphur substances originating during technological processes in malt and beer production can be a cause of various off-flavors and aromas. Their precursors are sulphur-containing amino acids. Sulphur substances play an important role in brewing as even in very low concentrations they can negatively affect total character of beer. Therefore, it is necessary to monitor volatile sulphur substances and their precursors to eliminate undesirable processes. Because sulphur substances occur in beer and raw materials at trace levels, microanalytical methods are used for their detection. This diploma thesis describes the problems of sulphur substances and their determination using the SPME/GC method.
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Analysis of selected strobilurine pesticides in barley, malt and beer
Stehlík, Pavel ; Kočí, Radka (referee) ; RNDr.Renata Mikulíková (advisor)
This diploma work is aimed determination of strobilurine pesticide in barly, malt and berr. Identifikation of strobilurine was made according to mass spectra library and base of commercialy standard. The next quantifikation in samples was made. The work consist of three main parts refer about problems. In therotical part is the method of plant, grown protection. This part is about pesticides and their fission, history and effects. In experimental part is method for determination strobilurine. In part results and discussion are all result and data in tables a graphs. At the end is sumed up result this work.
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Analysis of essences in some plant materials
Koloničná, Markéta ; Svoboda, Zdeněk (referee) ; Mikulíková, Renata (advisor)
The peppermint (Mentha piperita) and the levander (Lavandula angustifolia) are the aromatic herbs with the healing and spices effects. Their essencial oils serve to production of the aromatic substances, they are used in the cosmetic and the food industry. In this thesis were analyzed substances which are contained in levander and peppermint oils. These oils were extracted through the destillation with the water steam, next they were analyzed by the gas chromatograph and the mass spectrometer. The aim of the thesis was found which substances contain these oils. In the levander oils were proofed the highest amounts of the cineole, linalool and the linalyl-acetate. In the peppermint oils were proofed the highest amounts of the menthon and the menthol.
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Multirezidual analysis of selected pesticides in barley
Ehrenbergerová, Martina ; Duroňová, Kateřina (referee) ; Mikulíková, Renata (advisor)
Barley is one of the economically important crops. Its production is primarilly used as fodder barley and also in brewery and food industry. Particularly the part of its production intended for malt production must be of high quality. There are some important factors which can influence the quality of the crops, such as harmful organisms – diseases, pests and weed. In order to regulate the occurence of harmful organisms, agricultural measures are taken in the integrated protection system and resistant variants and pesticides are used. The higher the demand on the production quality, the bigger is the volume and the spectrum of pesticides used. The increasing extent of pesticide use also poses a risk for internal production quality and the environment. This fact makes it necessary to monitor unfavourable influences, including the contents of the pesticide residues in barley. This work studies the possibility of multiresidual determination of some selected pesticides in malting barley.
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