National Repository of Grey Literature 113 records found  beginprevious102 - 111next  jump to record: Search took 0.00 seconds. 
Comparison of content anthocyanin pigments in selected cultivars of black elderberry and grape
Becková, Eliška ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
The purpose of this thesis is to compare the contents anthocyans in different varieties of European elderberry (Sambucus nigra L.). It was also studied the relationship between the content anthocyans in selected samples of blue grape varieties (Vitis vinifera L.) and position of the track, where the grapes were grown. The theoretical part describes elderberries and grapes in terms of botanical, chemical, and in terms of their using in the food industry. The dominant part of this chapter is to describe anthocyans and possibilities for their determination in the elderberry and grapes. Emphasis has been placed on the pH-differential method and determination by high performance liquid chromatography. The experiments are divided into two parts. The aim of the first experimental part is comparison of the total anthocyanins content in fifteen varieties of elderberry. The performed analysis shows that in terms of anthocyanins content for cultivation of elderberry in the Czech Republic the most suitable varieties are Mammut, Samyl, Reis aus Vossloch and Haschberg. In the second part of the experiments were determined total anthocyanins content in nine varieties of blue grape grown in the Mikulov region. For determination were used HPLC and pH-differential methods, as well as in the first part. The highest content of pigments was found in varieties Alibernet and Neronet. The present study focused on the suitability of the location pointed to vineyard south to southeast orientation plantings. At the end of the experimental part is a comparison of both methods of determination. Method using high performance liquid chromatography to provide very accurate results compared to less demanding pH-differential method of determination. This is recommended only for tentative determination of anthocyanins content in real samples.
Analysis of main wine saccharides
Horáková, Hana ; Šabata, Pavel (referee) ; Vespalcová, Milena (advisor)
This diploma thesis deals with determination of carbohydrates in wine. Theoretical part attends to production of wine from grape to treatment and training of wine. It refers saccharides in wine, especially glucose and fructose. The study provides an overview of the available sources concerning the possibilities of determination of carbohydrates in wine by chromatographic methods and Skalar automated chemistry analyser. The study shortly refers simple analytical methods for determination of wine saccharides. The experimental part based on this search deals with analysis of saccharides by high performance liquid chromatography with refractive index detector and UV detector on aminoalkyl column and determination of reducting sugars by Skalar automated chemistry analyser. Finally, the results of these methods were compared.
HPLC determination of thiamine in barley, malt and food supplements
Vítková, Kateřina ; Běláková, Sylva (referee) ; Vespalcová, Milena (advisor)
The aim of this diploma thesis is focused on determination of B vitamin in food especially in malting barley and malt. This diploma thesis is consists of theoretical and experimental parts including the conclusion and supplements. Theoretical part describes thiamine characteristic, chemical structure, chemical and physical properties, function of thiamin in organism, impact it´s insufficiency to the human health, occurrence in common food and methods for it´s determination. Further are describing theoretical principles of high-efficiency liquid chromatography, chromatography on reverse phase, derivatization and ways of validation. In the Experimental section is detailed description of used method for determination of thiamine in barley and malt, fresh mash and beer but also in common food supplements as are B-kompex, Pangamin and Thiamin. Determination was made by high-efficiency liquid chromatography on reverse phase with isocratic elution and fluorescent detection. Next part introduce the results of theses, discussion of experimental work, volume of thiamine in analyzed food and validation parameters of used method. In the conclusion are valorized results of experimental work. In the attachment are graphs of standard curves, chromatogram and calculations of validation parameters. Diploma thesis was realized in laboratory of Chemistry and Technology of Foodstuff, Faculty of chemistry, Brno University of Technology.
PCP sorption of lignite
Šnédarová, Gabriela ; Taraba, Boleslav (referee) ; Pekař, Miloslav (advisor)
Within the framework of this diploma thesis, the sorptive capability of a lignite as a natural adsorbent was applied on an aqueous solution of pentachlorophenol. The aqueous solution of this substance, which is very dangerous for the environment, was prepared in various concentration ranges according to reached solubility. The solubility is noticed in different literatures variously and then is not applicable. That is why it was necessary to find out the ”real“ solubility. The aqueous solution of pentachlorophenol of given concentration was subsequently put to adsorption with exactly defined quantity of the lignite and as a result the adsorptive isotherms were obtained. These isotherms represent the adsorption capability in dependence on the adsorption duration, quantity of used lignite and concentration of pentachlorophenol solution. By the adsorption with duration longer than one hour, the quantity of adsorbed PCP does not increase markedly.
Analysis of Echinacea content compounds
Michalíček, Jan ; Vespalcová, Milena (referee) ; Zemanová, Jana (advisor)
Rostliny rodu Echinacea jsou léčivé byliny stimulující imunitní systém. Používají se zvláště v boji proti chřipce a infekcím horních cest dýchacích. V této práci bylo analyzováno 7 komerčních výrobků obsahujících výtažky z rostliny Echinacea vysokoúčinnou kapalinovou chromatografií. Bylo provedeno kvantitativní stanovení derivátů kyseliny kávové, jež jsou látky zodpovědné za léčivé účinky rostliny. Zjištěné obsahy kyseliny chlorogenové, kávové, cichorové a echinakosidu byly porovnány v jednotlivých výrobcích. Dále byly připraveny extrakty z kořene, listů a květů třapatky nachové pomocí extrakce za zvýšeného tlaku extrakčního rozpouštědla při různých podmínkách, aby se z obsahu účinných látek v nich přítomných zjistilo, které extrakční podmínky jsou nejlepší. Z naměřených dat bylo zjištěno, že největší celková koncentrace obsahových látek je přítomna ve výrobku Imunit Echinaceové kapky firmy Simply You. Jako nejlepší extrakční podmínky se ukázaly teplota 80 °C v kombinaci s rozpouštědlem ve složení EtOH/voda = 40/60, a to jak při extrakci kořene, tak i listů a květů.
Determination of polycyclic aromatic hydrocarbons in foods
Ryšavý, Jan ; Ing.Božena Skláršová, Ph.D. (referee) ; Šimko, Peter (advisor)
This bachelor thesis is focused on the problematics of origin and occurrence of polycyclic aromatic hydrocarbons in food. The objectives of my thesis were to sumarise and compare isolating procedures for extraction of polycyclic aromatic hydrocarbons from food matrix and discusse analytical methods applied to determination of content of polycyclic aromatic hydrocarbons in food.
The effect of the treatment with elicitors on the content of some biologically active constituents in chosen plant
PETR, Jindřich
The aim of this thesis was to study the effect of the acetylsalicylic acid on the stimulation of plant immunity and thus the influence on the content of the active constituents in Silybum marianum L. plants. The main active constituents of Silybum marianum L. seeds are silybine, silydianine, isosilybine, silycristine, usually expressed as silymarine content, and taxifoline. These constituents have antihepatotoxic effect and many different protective effects on numerous organs and cells. Knowledge about stress and elicitation, origin, botanical characterization, growth, development and cultivation of Silybum marianum L. were summarized before the research.The small-plot experiment was set up in Hluboká nad Vltavou in 2013. Plants of Silybum marianum were divided into four groups and then three goups were treated three times during the vegetation with the acetylsalicylic acid of three different concentrations - 10-3 mol.l-1 (high), 10-4 mol.l-1 (medium) a 10-5 mol.l-1 (low). Every single one group was treated with only one concentration of the acetylsalicylic acid. The last group was treated only with water and served as a control group. The preparation of the extracts was being held with using mixture of acetone, methanol and water. The extracts were determined by High Performance Liquid Chromatography.The effects of each chosen concetration of acetylsalicylic acid (high, medium, low) on the active constituents in seeds were not statistically proven compared to seeds without aplication of the elicitor (control group). The ineffectiveness of the elicitor should have been also caused by nonoptimal condition of plants due to various abiotic and biotic stressors.
Content of selected phenolic compounds in spice plants.
BERANOVÁ, Zuzana
This work concerns the amount of certain phenols in some of the representatives of families Alliaceae, Lamiaceae and Apiaceae. Phenols in plants are widely represented and highly concentrated. Flavonoids are one of the smallest, yet quite significant classes of phenols. Ingestion of food containing flavonoids can prevent certain diseases such as Arteriosclerosis. cardiovascular and tumor diseases. This work focuses, for their special biological effects, on five flavonoids: Kaempferol, Quercetin, Myricetin, Apigenin and Luteolin. For determining the content of phenols a method of High-performance liquid chromatography (HPLC) was used. Three representative of the family Alliaceae, two representatives of the family Lamiaceae and three representatives of the family Apiaceae were analysed. Only edible parts of the plants were used for the analysis and the amount of phenols was compared in certain plants planted in beddings to the plants planted in greenhouses. At first, the qualitative representantion of phenols was ascertained by the HPLC method. The result is chromatographic profiles, which were then used in calculating the amount of particular phenols. Then the total amounts of kaempferol, quercetin, myricetin, apigenin and luteolin were found out thanks to HPLC method. The biggest amount of total kaempferol was determined in petroselium hortense planted in beddings (588 mg/kg of fresh sample) and in a greenhouse (340 mg/kg of fresh sample). The biggest amount of quercetin was determined in red onion planted in a greenhouse (773 mg/kg of fresh sample) and in ocimum basilicum planted in beddings (535 mg/kg of fresh sample). The biggest amount of apigenin was determined in petroselium hortense planted in a greenhouse (1790 mg/kg of fresh sample) and in petroselium chrispum planted in beddings (3690 mg/kg of fresh sample).
Optimization of conditions and procedures for plant extraction.
SMUTNÍKOVÁ, Kateřina
The thesis deals with the content of selected phenolic compounds in some species of the genus Amaranthus, in black elderberry (Sambucus nigra L.) and buckwheat (Fagopyrum esculentum M.). Phenolic compounds are a group of natural compounds exclusively vegetable character. Flavonoids represent only one group of phenolic compounds. Flavonoids show many positive biological effects, in particular act as antioxidants. Natural flavonoids may cause to prevent from coronary- heard diseases and other diseases associated with older age. In recent years the increased attention is paid to flavonoid investigation due to its biological effects. For the determination of phenolic substances there were used two independent analytical methods. There are the high-performance liquid chromatography (HPLC) and micellar electrokinetic capillary chromatography (MECC). The MECC method was used for determination rutin and free quercetin. The highest content of rutin was found in leaves of buckwheat (76,400 mg/kg of dry weight) and the lowest content of rutin was determined in buckwheat hulls. The highest content of rutin was observed in teas from buckwheat leaves and inflorescence. This amount of rutin corresponds with rutin content in more than two pills of Ascorutin (the most favourite flavonoid medicament in the Czech Republic) The HPLC method was used for quantitative determination of phenolic acids. The content of free quercetin was monitored in all samples. No free quercetin was found both in plant material and in samples of teas. The ethanolic extract from the elderberry inflorescence didn´t contain any free quercetin. Free quercetin wasn?t found in any further samples of teas, which were prepared by described methods.
The effect of the treatment with elicitors on the content of some biologically active constituents in chosen plant
PETR, Jindřich
The aim of this thesis was to study the effect of two different elicitors - ELITiC and Elitic Jack on the stimulation of plant immunity and thus the influence on the content of the active constituents in Silybum marianum L. plants. The main active constituents of Silybum marianum L. seeds are silybine, silydianine, isosilybine, silycristine, usually expressed as silymarine content, and taxifoline. These constituents have antihepatotoxic effect and many different protective effects on numerous organs and cells. Knowledge about stress and elicitation, origin, botanical characterization, growth, development and cultivation of Silybum marianum L. were summarized before the research. Then the small-plot experiment was set up in Hluboká nad Vltavou in 2010. Plants of Silybum marianum were treated three times with 2,000 ml of preparation ELITiC and 2,000 ml of preparation Elitic Jack both diluted in 5 l of water. The preparation of the extracts was being held with using mixture of acetone, methanol and water. The extracts were determined by High Performance Liquid Chromatography. The effects of both preparation ELITiC and preparation Elitic Jack on the active constituents in seeds were not statistically proven compared to seeds without aplication of elicitors. The ineffectiveness of elicitors should have been caused by unsuitable chosen concentration as well as by nonoptimal condition of plants due to various abiotic and biotic stressors.

National Repository of Grey Literature : 113 records found   beginprevious102 - 111next  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.