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Isolation and characterization of beta-glucans of natural origin
Ratsilouskaya, Lizaveta ; Hoová, Julie (referee) ; Márová, Ivana (advisor)
The bachelor thesis deals with the characterization of natural beta-glucans and other active substances isolated from macroalgae and yeasts. The used macroalgae samples differ in the pigment, origin and method of algae processing. The theoretical part focuses on seaweed and yeast species, beta-glucans, their sources and biological effects, other biologically active substances (such as polyphenols and antioxidants) and finally on methods for determining these biologically active substances. In the practical part, samples of selected macroalgae were analyzed, namely samples of Arame, Nori, Kombu, Wakame, Hijiki and Spaghetti. Aqueous, ethanol and acetone extracts of these algae were prepared in this work. The aqueous extracts were used for spectrophotometric determination of phenolic substances, flavonoids and antioxidant activity by the ABTS method. Furthermore, ethanol and acetone extracts of said macroalgae were used to determine total chlorophyll and carotenoid content spectrophotometric. The work also focused on beta-glucan content, analyzing macroalgae and yeast R. toruloides. Arame and Nori algae and R. toruloides were high in beta-glucans. However, beta-glucans were very low in other macroalgae.
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Pretreatment of hops for further processing in beer technology
Tichá, Anna ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with pre-treatment of hops for further processing in beer technology. In the experimental part of the work, the effect of low temperatures, as pre-treatment of hops, on the monitored parameters was observed. Three types of cold pretreatment were used. In two cases, the hop material was frozen using a freezer at -25 ° C and in the second case at -70 ° C. In the third case, the hop material was treated by contact with liquid nitrogen in combination with mechanical treatment. The variety of hop materiál was Žatecký poloraný červeňák, which were in the form of pellets or pressed hop cones. The total bitterness of the samples, the total content of phenolic substances, the total content of flavonoids, the antioxidant activity and the concentration of essential oils, specifically myrcene humulene and geraniol, were examined. The effect of pre-treatment was investigated during conventional worth boiling as well as dryhopping. The experimental part includes descriptions of the hopping process, descriptions of individual analytical methods. A parallel measurement was performed on each sample. Significant advantages or disadvantages of some of the pretreatments were not demonstrable, however, the most significant differences were observed in samples hopped with hops pretreated by freezing at -70 ° C, which had a positive effect on the amount of extracted essential oils during cold hops.
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Determination of selected phenolic and volatile substances in tea and tea infusion
Stará, Kristýna ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the determination of phenolic substances and volatile substances in teas and tea infusions. The work compares teas based on their production technology and country of origin. Phenolic substances were determined by LC / MS. Phenolic substances were divided into catechins and other substances. In methanol extracts, green teas contained higher concentrations of catechins than black teas. From the group of catechins, the highest concentration was found for epigallocatechin gallate in green tea, namely 7,96 mg / g. Black teas contained the most gallic acid of the studied teas. The highest content of gallic acid in black teas was set at 1,84 mg / g. Tea infusions were prepared according to the classic procedures typical for each type of tea. In the infusions, the concentrations of all substances were higher in black teas. Some substances such as gallocatechin gallate, quercetin, coumaric acid and kaempferol were not detected in the infusions of green tea. Volatiles were analyzed by HS-SPME-GC-MS. The aroma of the tea was characterized by the identification of volatile substances in tea leafs. The black teas were characterized by a rich floral and sweet aroma. The green teas were more of a fresh and grassy aroma. The substances linalool, linalyl anthranilate and -Terpinyl acetate were found in all teas.
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Basic chemical characteristics of cranberry juice
Cao, Ha Thuy ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis is about lingonberries and cranberries. It is mainly about berries which were used for chemical analysis. The berries are from the Research and Breeding Institute of Pomology Holovousy Ltd. and they have delivered six cultivars of lingonberries and three cultivars of cranberries. There is a research of general information about classification, botanical description, important chemical substances such as vitamins, natural colorants and products made in the industry. Furthermore there is descriprion of chemical methods for basic analysis. The next part of bachelor thesis is about how all these methods were applied to berry juice. What instruments and chemicals were used. First assessment was profit of juice which was about 50,00–60,00 %, but lingonberry Runo bilawskie has at least 31,49 % and cranberries have less profit too. Total solids were determined in the range of 11,40 % (Pilgrim) to 18,50 % (Runo bielawskie) and solitable solids are in range of 10,00 % (Pilgrim) to 16,08 % (Korál). Lingonberry contains more reducing sugars (8,81–12,92 %) than cranberry (7,90–9,03 %). Titratable acids are about 32,04–49,60 mmol.l-1 for lingonberry and about 55,40–60,67 mmol.l-1 for cranberry. The measurements show that pH of both berries are about 3. The most phenolic substances are found in range of 2187,11–3476,75 mg.l-1. Berries content anthocyans colorants in range of 54,91-65,29 mg.l-1 and the most in cranberry. All results are shown in charts and in the end there is a discussion and conclusion about methods and results.
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Possibility of further use of elderberry marc
Sedláčková, Lucie ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This Diploma thesis talks about the production of concentrates and lyophilisate from the extract of elderberry moldlings (elderberry, Sambuvus nigra L.) and by determination by chosen chemical characteristics of these products. The theoretical part includes the botanical characteristics of the plant species Sambucus nigra L. Next is the part that is dedicated to biologicaly active substances found in elderberry and it‘s possible usage in the food industry. Next is the part where the extraction, purification and indentification of anthocyanic dyes are described. In the next part is the analyrical method HPLC described, including the description of instrumentation. The last part talks about the description of the used methods: methods for the concentration of the extract, UV-VIS spectrophotometry, determination of phenolic compounds, determination of dry matter, determination of active acidity and the overall titrating acidity. The experimental part contained the optimalization of the process of producing the extract from elderberry moldings. The extract obtained was then concentrated for preservation and characterization purposes based on selected chemical properties. The total content of anthocyanin dyes was chosen as a quality parameter. The most suitable process for the preparation of the extract was chosen to be the ratio of moldings and solvent 1:2, 4 (m/V). The most suitable solvent was chosen to be a mixture of water and ethanol in a ratio of 1:1 (V/V). According to the needs of the submitter, an extract with the use of water as the extraction agent is also provided. The prepared extract was then concentrated on a vacuum evaporator or lyophilized for storage purposes. The dye degradation while using the evaporator was the lowest in a 40 ° C water bath. The final products were characterized by the determination of soluble solids, pH, titration acidity, total phenolic compounds and total anthocyanin dyes. The anthocyanin pigments contained identified by liquid chromatography are: cyanidine-3-sambubioside, cyanidine-3-glucoside, cyanidine-3-sambubioside-5-glucoside, and cyanidine-3,5-diglucoside The total content of anthocyanins in the concentrate was determined to be equivalent to cyanidine-3-glucoside at 2.8 gl-1 and in the lyophilisate 2.5 gl-1.
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Phenolic substances in algae
Ráček, Jan ; Pichrtová, Martina (advisor) ; Pilátová, Jana (referee)
Phenolic substances are considered to be a group of secondary metabolites, known primarily from land plants (Embryophyta). Their function is to absorb harmful ultraviolet radiation, to protect plants from grazing and to attract pollinators and seed spreaders. However, these compounds have also been reported in some phylogenetically unrelated algal groups, the most important of which are brown algae (Phaeophyceae), siphonous green algae from the Dasycladaceae family and conjugating algae (Zygnematophyceae). The aim of this work is to summarize the current knowledge about phenolic compounds of these groups with an emphasis on their significance for the biology of the species. The first part describes phenolic compounds in general and also outlines the way they are biosynthesized. The next chapters then deal with the three algae groups. The most explored ones in this area are brown algae, which contain a unique type of tannins called phlorotannins in their thallus. This is followed by green siphonous algae from the family Dasycladaceae, which synthesize sulphated coumarins and then conjugating algae in which gallic acid-based phenolic compounds have been found. The common feature of these substances is, as with land plants, the ability to absorb radiation from the ultraviolet part of the spectrum and...
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Influence of kitchen treatments on the content of phenolic substances in celery (Apium graveolens)
ŠIROKÁ, Johana
Phenolic substances were detected in the celery (Apium graveolens) in three species. Monitoring the phenolics were accomplished in the raw state of the plant, in the plant that was cooked, in the stock and in the dried state. In this master´s thesis are summarized results that were measured, methodology relating to the measurement as well as a description of cultivation of those plants. From the results arise that the smallest amount of phenolic substances has an extract from cooked celery. The biggest amount of phenolic substances is in the raw celery´s stalk as well as in the dried celery. In the celery were identified another three phenolics - Apigenin, Kaempferol, and Lureolin.
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The basic chemical parameters of several varieties of sour cherries
Komárek, Šimon ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
This bachelor thesis deals with determination of basic chemical parameters in sour cherry (Prunus cerasus). Three different cultivars Köröšská, Pandy 6039 and Šumadinka were examined. The content of total solids varied from 13,32 to 15,22 %, soluble solid content amounted for 12,04–14,60 %, ash 0,4 %, reducing sugars 4,9–6,9 %, nitrogenous substances 0,11–0,12 %, L-ascorbic acid 343–456 mg/kg. Titratable acidity ranged from 15,1 to 21,8 g malic acid equivalent/kg, formol number 268–373 ml of 0,1 NaOH/kg. Total anthocyanins varied from 308 to 1104 mg cyanidin 3-glucoside equivalent/kg and total phenolics ranged from 1,05 to 3,99 g gallic acid equivalent/kg. All data are applied to fresh fruit weight.
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The basic chemical parameters of several varieties of cherries
Boberová, Jana ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
This bachelor thesis deals with determination of basic chemical parameters in sweet cherry (Prunus avium). In the theoretical part, the taxonomic classification of the cherry, its botanical characteristics and the pomology of several cultivars are mentioned. Also, the history of cultivation, appropriate conditions and most common diseases are listed. The last chapter deals with the chemical composition of the fruits. In the experimental part, the determination of selected chemical parameters of various cultivars (Karešova, Napoleonova and Stark Gold) were determined. The content of total solids was determined in the range of 14.53–18.15 %, soluble solids 13.96–16.44 %, ash 0.34–0.44 %, reducing sugars 6.89–10.18 % and nitrogenous substances 0.056–0.116 %. Ascorbic acid content was set at 26.1–44.1 mg/kg. The titratable acidity was determined in the range of 6.15–8.86 g of predominant malic acid in 1 kg of cherry and a formol number was determined from 194 to 297 ml of 0.1 M NaOH per 1 kg of edible fraction. The amount of anthocyanins was determined at 4–686 mg cyanidin-3-rutinoside/kg and total phenolic compounds at 0.91–1.47 g gallic acid/kg. All data are based on fresh fruit weight.
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The content of selected fenolic compounds in medicinal plants.
KREJČÍ, Zuzana
The work has been inquired into the problem of content determination of phenolic substances in medicinal plants traditionally used in Czech Republic. Phenolic substances belong to a group of natural compounds, which are purely plant origin. Flavonoids are a part of this extensive group of compounds. As for flavonoids, most attention is paid to quercetin and rutin. It is caused by their easy availability and very significant biological activity. These compounds embody a lot of positive biological effects. They have expressive antioxidant properties, inhibit lipid peroxidation, scavenge free oxygen radicals and bond into the chelates they inactivate some prooxidant metal ions. The latest researches have shown that thanks to their properties natural flavonoids can occurence of chronical diseases, such as arterosklerosis, cardiovascular or tumor disorder. Flavonoids are exploited both in traditional and modern medicine. Same other studies have evidenced that valuable sources of these biologically effective substances are traditionally used medicinal plants. Content of phenolic substances was determined by method of micellar electrokinetic capillary chromatography (MECC) and liquid chromatography (HPLC) in collection of 8 medicinal plants usually used in Czech Republic. For analysis was used freeze-dried and dried plant material. In freeze-dried material was found the highest content of total quercetin in Filipendula ulmaria L. (14200 mg/kg of dry weight) and in Betula pendula Roth. (11800 mg/kg of dry weight). The highest content of rutin contained Sambucus nigra L. (17700 mg/kg of dry weight). Similar values was measured in dried plant material. The content of total quercetin and rutin during drying was unchanged.
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