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Assessment of aroma active compounds in selected type of cheese
Dostálková, Andrea ; Sýkora, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the aroma active compounds of Emmental and Moravský bochník types of cheeses, i.e. natural hard cheese with high heat curd. In the theoretical part these cheeses are characterized, their chemical composition is described as well as individual steps of their manufacturing process. After that a literature search focused on aroma active substances is made and the following methods are described: solid phase microextraction for their isolation and gas chromatography with mass spectrometry for detection. In the experimental part the selected SPME-GC-MS method is used to identify volatile aroma active compounds in cheeses with high heat curd bought on the market and samples of model cheeses manufactured at Tomas Bata University in Zlín with the use of various ratios of added dairy cultures. The differences among samples were found in the number and types of volatile compounds. A total of 129 compounds were identified in samples; of those 35 alcohols, 9 aldehydes, 24 ketones, 16 carboxylic acids, 23 esters, 1 ether, 16 hydrocarbons, 2 sulphurous and 3 nitrogenous compounds.
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Analysis of sensorially active substances contained herbal extracts
Koloničná, Markéta ; Vítová, Eva (referee) ; Mikulíková, Renata (advisor)
The peppermint (Mentha piperita), the salvia (Salvia officinalis), the lemon balm (Melissa oficinalis), the camomile (Matricaria chamomilla) and the valerian (Valeriana officinalis) are herbs with healing effects. Their ethanol extracts are used for food fortification or in a cosmetic industry. Substances contained in herbal extracts were analyzed in this thesis. The extracts were prepared by maceration. Next, they were analyzed by using a gas chromatography and a mass spectrometry. The aim of this thesis was an optimalization of the method used for the analysis of sensorially active substances. Then, herbal extracts were analyzed and concentration of sensorially active substances was determined.
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Changes of aroma active compounds during production of model cheese
Školová, Dominika ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
The aim of the work was identification of aroma active compounds in Moravský bochník cheese type, than discuss their changes during ripening and consider influence of aplication different rates of microbial cultures on number of volatile compounds. SPME-GC-MS was used for identification of volatile compounds. In total, 148 of volatile compounds were identified and 82 of them are considered as aroma active compounds. Three microbial cultures (their combination with predominant thermophilic or mesophilic culture) were used for making samples. The influence of predominant thermophilic/mesophilic culture on number of volatile compounds was not proved. From the point of view of sensory quality, combinations with predominant mesophilic culture proved to be more successful. During ripening, the number of identified compounds was reduced in all the combinations of cultures studied. The optimal time for ripening seems to be three months.
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Aroma active compounds of selected types of medical herbs
Pecinová, Ester ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
This thesis deals with aroma active compounds of selected types of medicinal herbs, specifically lavender (Lavandula officinalis), peppermint (Mentha piperita), sage (Salvia officinalis), St. John’s wort (Hypericum perforatum) and hyssop (Hyssopus officinalis). In the theoretical part the single herbs were characterized including botanical description, chemical composition, medicinal properties, adverse effects and the practical use; aroma active compounds present in herbs are also emphasized. Based on the literature search, gas chromatography coupled with mass spectrometry as currently the most frequently used method, was chosen for the assessment of aroma compounds. Solid Phase Microextraction was used for isolation of volatile compounds from dried herbs. Within experimental part of the work selected parameters of the SPME-GC-MS method were optimized, aroma compounds in samples of herbs were identified, and twenty four suspected fragrance allergens due to the Regulation (EC) N° 1223/2009 were also identified and quantified. Overall 69 compounds were indetified together with 2 allergens in lavender, 59 compounds including 5 allergens in peppermint, sage contained 49 compounds with 4 allergens included, 41 compounds were identified in St. John’s wort including 4 allergens and finally 64 compounds with 4 allergens included in hyssop.
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Neuroactive steroids in human physiology and pathophysiology
Kubátová, Jana ; Hill, Martin (advisor) ; Fanta, Michal (referee)
The present diploma thesis is focused on the evaluation of steroid metabolome in body fluids in human pregnancy and parturition and also concentrates on the estimation of steroids in men with epilepsy (MWE) regarding the influence of epilepsy and its treatment with antiepileptic drugs (AEDs). The results obtained eventuate to the following conclusions: 1. They support the proposition about the key importance of corticoliberin for the timing of human parturition via stimulation of the steroidogenesis in the fetal zone of the fetal adrenal (FZ). Changes in steroid levels, however, much better predict the timing of parturition than the variation in corticoliberin. 2. The distribution of isoforms of placental oxidoreductases determines the excess of oxidized forms of the sex steroids and NAS in the fetus and the excess of their reduced forms in mother. This mechanism fundamentally affects the steroid bioactivity. The results indicate the role of NAS in pregnancy sustaining, their analgesic effect around parturition and their role in the pathophysiology of postpartum blues.
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Comparison of HPLC a GC-MS method for pesticide determination in soil
Chalbia Václavíková, Alena ; Kočárek, Martin (advisor) ; Havlík, Jaroslav (referee)
Physical and chemical properties of pesticides may vary significantly. Pesticides can be acidic, neutral or alkaline. Some compounds containing phosphorus, other sulfur, nitrogen or halogens. These atoms can be important for the detection of pesticides. Some of the compounds are volatile, others on the contrary not evaporate, which is also one of the important properties for chromatography. The diversity of pesticides actually makes it impossible to create a universal method, which is very impractical in terms of quality and time determination. Because that pesticides are one of the most chemicals in most countries. In the food and drinking water are limits on pesticides in order to avoid negative impact on public health. For residues in soil or surface water limits are set. (Lutz et al., 2006)
The objective of this thesis is to evaluate the possibility of using two types of chromatographs with different detectors for the analysis of pesticide. Pendimethalin which was chosen for this work, will be analyzed usinga liquid chromatograph with UV detektor and gas chromatography with mass detector. Both this method will be compared as well two extraction methods (Soxhlet extraction and shaking), and two extraction agents (methanol and acetonitrile).
Another point of the work is to provethe hypothesis that, for the determination of pendimethalin in soil is by gas chromatography using a mass spectrometer in comparison with the high performance liquid chromatography time and more expensive, but will achieve a higher yield and a lower detection limit of the pesticide.
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Monitoring of Volatile Compounds in Dry Dog Foods
Šímová, Lenka ; Nový, Pavel (advisor) ; Adéla, Adéla (referee)
The aim of this study was to explore the influence of volatile compounds in dry dog food on its attractiveness for dogs. The assumption was that the attractiveness is mainly affected by volatile compounds presented in the feed.
This study brings overall information about dog´s digestive system and its nutritional requirements with the summary of available feeds including the production process and list of the customary ingredients. A survey of the most common volatile compounds including appropriate analytical methods is also part of this study.
A feed preference test was performed in experimental part of this study. The preference ratio of two dry dog diets was set to 21:79 % that shows clear preference for one of the feeds.
Chemical analysis using gas chromatography-mass spectrometry revealed distinctions in the volatile compounds profile of the tested feeds. 3-tert-butyl-4-hydroxyanisole that is part of synthetic antioxidant BHA was identified to be the main volatile compound that could possibly be responsible for feed preferences observed in this study.
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Synthetic aromatic substances in wastewaters
Tylichová, Petra ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Synthetic fragrances are artificially synthetised organic compounds which are used as fragrant substances in assorted personal care products, perfumes, cosmetics, soaps, detergents, cleansing articles, etc. So-called musk compounds creates significant group of synthetic fragrances which are distinguished by specific fragrance reminiscent of musk. Recently great attention is devoted to musk compounds because they were proved in different units of environment. The aim of diploma thesis was determination of selected linear musk compounds (arocet, aroflorone, linalool 925, lilial, isoamyl salicylate) in real samples of waste water in the influent and effluent from the sewage treatment plant Brno-Modřice. At first optimization of selected method was performed and then this method was used for own determination. Analytes were extracted by solid phase microextraction (SPME) from sample. Method of gas chromatography with mass spectrometry was used for own analysis. The results were used for evaluation of efficiency of removing linear musk compounds from waste water.
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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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