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Antioxidative parameters of fruit model product.
KRATOCHVÍLOVÁ, Lenka
The content of the main components (anthocyanins, quercetin, chlorogenic acid, L-ascorbic acid, rutin, total polyphenols) was determined in the syrup of elderberries (Sambucus nigra L.) by spectrophotometry or high-performanceliquid chromatography. Furthermore, the antioxidant activity of this syrup was determined using three methods: ABTS, FRAP, and DPPH. The measurement results were statistically processed and compared using correlation analysis, specifically using the Pearson correlation coefficient. It was found that the prepared product contains 2160 mg/kg anthocyanins, 201 mg/kg rutin, 26 mg/kg chlorogenic acid and 679 mg/l polyphenols. No free quercetin was found. The content of L-ascorbic acid in the original elderberries was relatively low and therefore for study purposes, the syrup was enriched with this substance in the amount of 0.5% (w/w) to study the connection of its content with other substances. It is clear from the statistical processing that the concentration of chlorogenic acid correlates with the antioxidant activity measured by the FRAP method and the concentration of polyphenols to the antioxidant activity measured by the DPPH method.
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Vývoj, optimalizace a validace analytické metody na stanovení kyseliny chikorové a dalších derivátů kyseliny kávové pomocí LC/MS
PAZDERKOVÁ, Nela
This thesis deals with the development, optimization, and validation of an analytical method for the determination of chicoric acid and other caffeic acid derivates using LC/MS. First, the development and optimization of the analytical method was conducted. The following parameters were selected for the optimization: mobile phase composition and flow rate injection volume capillary temperature, voltage S-lens and F-lens voltage, ion injection time, product ion selection, and collision energy. Then, the analytical method was successfully validated and tested for quantitative analysis in a range of Echinacea food matrixes - tea, tablet, and tincture.
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Biologically active phenolic compounds in small fruit.
LAXOVÁ, Lenka
This master´s thesis focuses at bioactive compounds in edible berries during its culinary processing. Elderberries (Sambucus nigra L.) were selected as a representative of edible berries variety. Elderberry is known for presence of significant bioactive compound content and usage in traditional medicine. Elderberries were processed acording to common culinary recipes. Amount od selected bioactive polyphenolic compounds (chlorogenic acid, quercetin, rutin, anthocyanes) was detected accordingly. Additionally content of ascorbic acid was determined. On the basis of the experimental determination, it was found that anthocyanes and rutin are the most common compounds found in elderberries. All analytes in juices and sirups gradually decreased during the treatments and long-term storage. On the contrary, the content of quercetin increased with gradual modifications and storage. The highest decrease was observed for vitamin C content. The lowest values in the products from elderberries were reached by quercetin and ascorbic acid.
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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.
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