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A strategy of acrylamide elimination in cereal foods
Belková, Renáta ; Ing.Kristína Kukurová, Ph.D. (referee) ; Ciesarová, Zuzana (advisor)
Acrylamide is a carcinogenic substance generated in heat processed food stuff, where the temperature increases over 120 °C. The main acrylamide precursors are carbonyl compounds and the amino acid asparagine. In this diploma work, possible elimination strategies were observed in a bread matrix with an addition of inorganic salts into the basic powder formulation for home bread making. Samples were analyzed from the point of view of acrylamide content as well as their physico-chemical properties and sensory evaluation too. Results show, that the addition of inorganic salts hasn`t expected considerable elimination impact as in the case of model samples. It has been shown the importance of fermentation process, whereas was the amount of acrylamide in bread without yeast added almost 14times higher. The addition of CaCl2 in bread mixture improved the organoleptic quality of final product, as proved in sensory evaluation with simultaneus positive effect on acrylamide reduction in bread.
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Determination of selected substances in phytopharmaceuticals
Hroncová, Michala ; Tulková, Tereza (referee) ; Vávrová, Milada (advisor)
Thyme, linden and cuban oregano are plant that have positive effect of upper respiratory tract infections. The most common are used in the form of teas and syrups. In this thesis were analyzed methods, which are used to specify substances in plants. It describe methods like stem distillation, SPME and GC/MS. The main aim of the thesis was found out subsances, which occur in herbs. Thymol was the substance which was found in every analyzed herb. The thyme contain o-cymen, in mixture of thyme was proofed thymol, borneol, 1-octene- 3- ol, linalol, estragol a 4- terpeneol. The linden has substances estragol a - terpinen. Characteristic substancies od the mixture of linden were o-cymen, estragol a - terpinen. In the cuban oregano were proofed – pinen, camphor, - terpinen. The method SPME was used to analyzed substances in syrup and main substances were thymol a -elemen.
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Use of derivatization methods in gas chromatography
Kaprinay Bréda, Boglárka ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This study is focused on verifying the possibility of derivatization in gas chromatography for the determination of fatty acids in oil samples and on the use of derivatization for the determination of organic substances in a sample of vine seed extract. The theoretical part deals with the characteristics of individual analytes. In the next section derivatization methods and transesterifications for fatty acid determination are described. The last chapter deals with the basic knowledge of gas chromatography and its instrumentation. The experimental part was divided into three chapters: analysis of fatty acids by transesterification, determination of mono- , di-, and triglycerides by derivatization and analysis of grape seed extracts. Three types of oils were analyzed in the experimental part: poppy, linseed and nut oil. The most common fatty acids in plant oils are palmitic, stearic, oleic, linoleic and linolenic acids. The optimization method was carried out using the derivatizing agent MSTFA. The determination of fatty acid methyl esters was measured on a gas chromatograph with a flame ionization detector. To confirm the presence of fatty acids, additional analysis was used on gas chromatograph with a mass spectrometer. Analysis of the grape extract was also performed on GC/MS. The method was most convenient using MSTFA, BSTFA and BSA+ TMCS derivatizing agents.
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Molecular study of lipids in humic acids by sequential chemical degradation
Bachratá, Radka ; Grasset, Laurent (referee) ; Klučáková, Martina (advisor)
Lipidy v půdě vykazují poměrně vysokou resistenci k biodegradaci, mohou proto tak zajistit informace o zdrojích organické hmoty a diagenetických procesech. Půdní organická hmota je vysoce heterogenní a vyskytují se v ní různé dynamické systémy. Vztahy mezi těmito systémy a molekulární strukturou ještě nejsou úplně známy. Analýza lipidů a bitumenu byla provedena u dvou vzroků (rašelina a lignit). Množství skupin sloučenin (volné uhlovodíky a volné ketony, vázané alkoholy, vázané mastné kyseliny, vázané -hydroxy kyseliny, volné dikyseliny a polycyklické sloučeniny) bylo idetifikováno pro oba vzorky a jejich distribuce byly určeny. GC/MS analýza volných a vázaných lipidů zjistila jejich různé zdroje během chemické degradace. Některé podobné znaky mohou být znakem uchovávání části vosků a suberinu z vyšších rostlin (dlouhé řetězce vázaných mastných kyselin). Velké rozdíly v molekulárním složení lipidů byly pozorovány mezi vzorky, dokládající význam studia lipidů z mladého sedimentu (rašelina) a starého (lignit).
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Determination of substances content in mint
Novotná, Martina ; Zlámalová Gargošová, Helena (referee) ; Vávrová, Milada (advisor)
This Bachelor thesis deals with determination of the content substances in mint (Mentha). Mint is in pharmacy very popular herb, it is been used for over 2000 years. We know many species of mint. Peppermint (Mentha piperita) is the most favorite and most common species. In the theoretical part there is description of substances found in plants, the characteristic of mint and principles of used analytical methods. Practical part of this thesis describes substances found in examined teas.
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Compounds of terpenic nature in mint plants and the influence of elicitation on them
Jančová, Nikola ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Diploma thesis is focused on study of compounds of terpenic nature in mint plants. Terpenic compounds are volatile hydrocarbons formed by several isoprenoid units with low molecular weight which cause the typical smell of plants. Presence of these compounds cause that plants seem to be fungicidal, bactericidal and insecticidal. Due to these properties, they can be used as botanical pesticides which are not toxic and no resistant organisms occur. Each plant contains relatively low concentrations of these compounds and therefore elicitors must be used for the increasing of terpenes amount. Elicitors activate defensive mechanisms in the plant leading to higher defense abilities and production of secondary metabolites. The identification and quantification of analytes was determined by gas chromatography in connection with mass spectrometry.
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Chemical analysis of organic residues in archaeological ceramic vessels
Bunžová, Aneta ; Mravcová, Ludmila (referee) ; Čáslavský, Josef (advisor)
The presented bachelor thesis deals with the analysis of organic residues in archaeological ceramic vessels. Apart from theoretical characterisation of residues, the thesis focuses on the possibility of the extraction of residues and subsequent analysis, which is executed on real samples from archaeological sites. In the research, two different derivatizational reagents were used for the subsequent determination using the technique of gas chromatography in combination with mass spectrometry (GC/MS). The thesis endeavours to certain extent to sketch the diet of the users of the analyzed ceramic vessels.
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Use of various extraction techniques for the analysis of biochar extracts
Jakubčeková, Kristína ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
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