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Production of agar candy with the addition of plant extract
Kameníková, Magda ; Gross, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the optimization of the production of jelly confectionery with agar as gelling agent, application of herbal extract to the prepared confectionery and subsequent identification of the content of aromatic active substances, characterization of phenolic content, antioxidant and antimicrobial activity and sensory quality. Calendula officinalis was selected as the source of the herbal extract, which is known for its high content of bioactive compounds. Determination of aromatic compounds was carried out by gas chromatography with mass detection, antioxidant activity by DPPH method, antimicrobial activity by diffusion method, determination of total phenolics by Folin-Ciocalteu method and sensory analysis was also carried out. Based on the sensory analysis, the optimum added amount of agar, extract and citric acid was determined. The additions of 1,25 % agar and 1 % acid were found to be optimal. The most sensory acceptable sample was the one without extract, while the sample with extract was the one with 4 % extract. The sample with Calendula extract of the above-mentioned optimal composition contained 14 identified aromatic compounds, of which guaiol, -cadinol and -muurolol were the most abundant; the total phenolic content was 464.30 ± 14.99 µgGAEg-1, and the antioxidant activity was determined to be 1.73 ± 0.01 mgTEACg-1 (or a radical quenching of 74.36 %). The antimicrobial effects of the above extract were tested against Gram-negative Escherichia coli and Gram-positive Bacillus cereus. The highest antimicrobial activity was exhibited by the extract alone and among the samples, it was the sample containing 4 % of the extract. The extract appeared to be more effective against B. cereus than E. coli. The results show that the content of extract in the samples increases their nutritional value and antimicrobial efficacy (increases the content of antioxidant and phenolic compounds).
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Freeze-dried fermented dairy products
Omelková, Viktorie ; Slavíková, Zuzana (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the production of yogurt, his lyophilization and reconstitution. By comparing all three forms of yoghurt in terms of sensory quality and volatile profile. The theoretical part deals with a characterization of fermented milk products, their production technology, lyophilization process, sensory quality and possibilities of determination of volatile compounds in yoghurt samples. In the experimental part of the thesis, a model sample of white yoghurt was produced and subsequently lyophilized. Freeze-dried yoghurt was first subjected to a consumer evaluation, where the general opinion of potential consumers on this type of product was investigated. The results show that it potentially could be applied on the market as a durable product. In the next phase, the lyophilized yoghurt was reconstituted again with the addition of water, from the point of view of a texture, the addition of approximately 30 % of the originally taken amount of water turned out to be optimal. The reconstituted yoghurt was then compared with the freshly made yoghurt, which was, as expected, rated as better, which could have contributed mainly to the positively rated aroma and the flavour. In reconstituted yoghurts, some evaluators detected an overly sour, bitter taste or an aftertaste of dried milk. Finally, all three types of yoghurt (fresh vs. freeze-dried vs. reconstituted) were compared in terms of volatile profile determined using solid phase microextraction combined with gas chromatography with mass detection. In total, 51 volatile substances were identified in all samples. The composition of the samples differed mainly in terms of the content of identified compounds, the most represented compounds were alcohols, followed by acids and ketones.
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Detection of aromatic compounds in plants
Tilešová, Kristína ; Zlámalová Gargošová, Helena (referee) ; Krčma, František (advisor)
This bachelor thesis is focused on the detection of aromatic compounds in plants. Selected plant was Celery (Apium graveolens). In the theoretical part, methods for the volatile substances analysis were reviewed. In the experimental part, celery sample was converted from solid to liquid form and then analyzed using proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) and gas chromatography-mass spectrometry (GC/MS). Aromatic compounds with a stronger signal were selected using PTR-TOF-MS, which were analyzed and identified using GC/MS. Monoterpenes represented the main group of compounds in celery seed essential oil, the most important is D-Limonene. Celery also contains phthalides, aldehydes, alcohols, esters. Using a combination of PTR-TOF-MS and GC/MS was obtained the quantitative and qualitative composition of celery essential oil.
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Influence of coffee making process on chemical composition of brewed coffee
Trenzová, Kristina ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the influence of baristic coffee preparations on the chemical composition of the obtained beverage. Teoretical part of this thesis focuses on coffee growing, processing technology and the chemical composition of coffee beans. In the experimental part were measured samples of espresso coffee, samples prepared by moca pot, flip-drip method, filtrated coffee, samples prepared by french-press technique, vacuum pot samples and boiled coffee. The samples were prepared according to the baristic techniques at first and later with adjusted water and amount of coffee so these methods could be compared with each other. This work focuses on the determination of caffeine and acrylamide content by liquid chromatography, validation of HPLC method, determination of total phenolic content by Folin-Ciocalteu reagent, determination of organic acids by ion chromatography, determination of selected macro and micro elements by inductively coupled plasma in optical emission spectrometry and analysis of aromatic substances using gas chromatography. Based on the processed results and compared methods, it was shown that the moca pot had the greatest influence on the content of caffeine, acrylamide, organic acids and total phenolic substances, and the flip-drip with vacuum pot method had the greatest influence on the content of aromatic substances. From a baristic point of view the highest concentration of caffeine was 3689 mg/l in coffee based on flip-drip method, and concentration of acrylamide was 25,4 mg/l in the coffee based on the same method. The highest value of total phenolic content was determined in moka pot to c = 5,23 g/l. Regarding the mineral representation, the mineral decomposition of coffee beans and espresso were compared, and the highest values were reached by potassium, namely the concentration was 577 mg/l per 1 g of mineralized sample, in the cup of espresso the potassium concentration was 2461 mg/l. The highest content of organic acids was determined in the beverage prepared by moca pot, in terms of selected acids, the largest representation had the succinic acid with the concentration 599,8 mg/l. The highest content of aromatic substances was found in coffee from a moca pot and in coffee by flip-drip method. The biggest part was~made by furfuryl alcohol.
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Influence of selected coffee bean roasting technology on its chemical composition
Šajdlerová, Kristýna ; Mikulíková, Renata (referee) ; Diviš, Pavel (advisor)
The subject of this diploma thesis is the monitoring of chemical changes taking place in the coffee bean during roasting using various devices. For these purposes an industrial coffee roaster and a home roaster were used in the practical part. The theoretical part deals mainly with the characterization of coffee beans in terms of the content of various compounds and a description of the changes that occur during roasting. Different types of roasting machines are also presented. In the experimental part the roasting of coffee beans and the determination of the concentration of selected substances in the samples taken during roasting were performed. The monitored parameters included the concentration of sucrose, organic acids (citric, acetic, lactic, malic, formic and chlorogenic), caffeine and aromatic substances. One of the biggest differences found between the both roasters is the reduction in the concentration of chlorogenic acid, which decreased by 33 % for domestic equipment, while the decrease was almost doubled for industrial roasters. Another significant difference was also observed in the change in sucrose content. Sucrose degradation occurred in 94 % of coffee bean samples roasted on an industrial roaster, while only 75 % of the second type of roaster.
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Development of New Syntheses of Azaaromatic Compounds with Extended π-System
Ulč, Jan ; Kotora, Martin (advisor) ; Hrdina, Radim (referee) ; Tobrman, Tomáš (referee)
Azapolyaromatic compound are a class of heterocyclic compounds, which contains at least one nitrogen atom. A subclass of these compounds are quinolizinium salts, which contains nitrogen atom in bridgehead position. These salts usually have interesting photophysical properties. Naphthoquinolizinium salts are a group of quinolizinium salts, but their synthesis as well as their photophysical properties haven't been studied in detail yet. This work is about development of a new modular method for preparation of naphthoquinoliziniu salts. This method is based on catalytic C-C and C-H bond activations by transition metal catalysts. 1-Azabiphenylene was used as a starting material, which reacted in catalytic C-C bond cleavage followed by insertion of various alkyne to form benzo[h]quinolines. These benzo[h]quinolines then reacted in catalytic C-H bond activation reaction followed by insertion of another alkyne to form final tetrasubstituted naphthoquinolizinium salts. Photophysical properties of the prepared salts was studied. The developed method was used on a more complex starting material such as linear 1- 1-aza-[3]triphenylene, which was converted to phenanthroquinolines and eventually to the corresponding azonia salts. Key words: azapolyaromatic compounds, catalysis by transition metal complexes, C-C...
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Influence of selected coffee bean roasting technology on its chemical composition
Šajdlerová, Kristýna ; Mikulíková, Renata (referee) ; Diviš, Pavel (advisor)
The subject of this diploma thesis is the monitoring of chemical changes taking place in the coffee bean during roasting using various devices. For these purposes an industrial coffee roaster and a home roaster were used in the practical part. The theoretical part deals mainly with the characterization of coffee beans in terms of the content of various compounds and a description of the changes that occur during roasting. Different types of roasting machines are also presented. In the experimental part the roasting of coffee beans and the determination of the concentration of selected substances in the samples taken during roasting were performed. The monitored parameters included the concentration of sucrose, organic acids (citric, acetic, lactic, malic, formic and chlorogenic), caffeine and aromatic substances. One of the biggest differences found between the both roasters is the reduction in the concentration of chlorogenic acid, which decreased by 33 % for domestic equipment, while the decrease was almost doubled for industrial roasters. Another significant difference was also observed in the change in sucrose content. Sucrose degradation occurred in 94 % of coffee bean samples roasted on an industrial roaster, while only 75 % of the second type of roaster.
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Characterization of organogold compounds
Shcherbachenko, Elena ; Roithová, Jana (advisor) ; Míšek, Jiří (referee)
Geminally diaurated complexes are important intermediates involved in some of the gold catalyzed reactions and therefore they have become a subject of the current research. The aim of this thesis was to assess the influence of electronic structure of an aryl ligand on the stability of gold complexes with three-center-two-electron interaction Au2C. A series of geminally diaurated complexes was obtained by a reaction of gold complex [(IPr)Au(NCMe)]BF4 (IPr = 1,3-bis(2,6-di-iso-propylphenyl)imidazol-2-ylidene) with arylboronic acids ArB(OH)2 bearing different substituents at the aryl group (Ar = para- O2NC6H4, para-NCC6H4, para-ClC6H4, C6H5, para-H3CC6H4, para-H3COC6H4, meta- O2NC6H4, meta-NCC6H4, meta-H3CC6H4, ortho-O2NC6H4, ortho-NCC6H4, ortho-H3CC6H4). Mass spectrometry (MS) was used as the main experimental method in this study. Appearance energies (AE) for the fragmentation of geminally diaurated complexes were estimated by the methods MS/MS. The obtained energies were plotted against the corresponding Hammett σ-constants to assess the correlation between the electronic structure of a given aryl ligand and the stability of the Au2C bond. It was found that structures of gold complexes derived from the cyanophenylboronic acids do not correspond to the geminally diaurated complexes but to the...
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Influence of coffee making process on chemical composition of brewed coffee
Trenzová, Kristina ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the influence of baristic coffee preparations on the chemical composition of the obtained beverage. Teoretical part of this thesis focuses on coffee growing, processing technology and the chemical composition of coffee beans. In the experimental part were measured samples of espresso coffee, samples prepared by moca pot, flip-drip method, filtrated coffee, samples prepared by french-press technique, vacuum pot samples and boiled coffee. The samples were prepared according to the baristic techniques at first and later with adjusted water and amount of coffee so these methods could be compared with each other. This work focuses on the determination of caffeine and acrylamide content by liquid chromatography, validation of HPLC method, determination of total phenolic content by Folin-Ciocalteu reagent, determination of organic acids by ion chromatography, determination of selected macro and micro elements by inductively coupled plasma in optical emission spectrometry and analysis of aromatic substances using gas chromatography. Based on the processed results and compared methods, it was shown that the moca pot had the greatest influence on the content of caffeine, acrylamide, organic acids and total phenolic substances, and the flip-drip with vacuum pot method had the greatest influence on the content of aromatic substances. From a baristic point of view the highest concentration of caffeine was 3689 mg/l in coffee based on flip-drip method, and concentration of acrylamide was 25,4 mg/l in the coffee based on the same method. The highest value of total phenolic content was determined in moka pot to c = 5,23 g/l. Regarding the mineral representation, the mineral decomposition of coffee beans and espresso were compared, and the highest values were reached by potassium, namely the concentration was 577 mg/l per 1 g of mineralized sample, in the cup of espresso the potassium concentration was 2461 mg/l. The highest content of organic acids was determined in the beverage prepared by moca pot, in terms of selected acids, the largest representation had the succinic acid with the concentration 599,8 mg/l. The highest content of aromatic substances was found in coffee from a moca pot and in coffee by flip-drip method. The biggest part was~made by furfuryl alcohol.
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Characterization of organogold compounds
Shcherbachenko, Elena ; Roithová, Jana (advisor) ; Míšek, Jiří (referee)
Geminally diaurated complexes are important intermediates involved in some of the gold catalyzed reactions and therefore they have become a subject of the current research. The aim of this thesis was to assess the influence of electronic structure of an aryl ligand on the stability of gold complexes with three-center-two-electron interaction Au2C. A series of geminally diaurated complexes was obtained by a reaction of gold complex [(IPr)Au(NCMe)]BF4 (IPr = 1,3-bis(2,6-di-iso-propylphenyl)imidazol-2-ylidene) with arylboronic acids ArB(OH)2 bearing different substituents at the aryl group (Ar = para- O2NC6H4, para-NCC6H4, para-ClC6H4, C6H5, para-H3CC6H4, para-H3COC6H4, meta- O2NC6H4, meta-NCC6H4, meta-H3CC6H4, ortho-O2NC6H4, ortho-NCC6H4, ortho-H3CC6H4). Mass spectrometry (MS) was used as the main experimental method in this study. Appearance energies (AE) for the fragmentation of geminally diaurated complexes were estimated by the methods MS/MS. The obtained energies were plotted against the corresponding Hammett σ-constants to assess the correlation between the electronic structure of a given aryl ligand and the stability of the Au2C bond. It was found that structures of gold complexes derived from the cyanophenylboronic acids do not correspond to the geminally diaurated complexes but to the...
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