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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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Determination of athenticity of plant foods by molecular techniques
Plášková, Anna ; Mikulíková, Renata (referee) ; Němcová, Andrea (advisor)
The aim of presented diploma thesis was to determination of authenticity of fruit baby foods for early infant feeding using molecular methods. In the experimental part, isolation kit was used for isolation of plant DNA from fruits (strawberry, apricot, raspberry, apple) and from six commercial fruit products for children. Isolated DNA was characterized and verified using PCR methods with primers specific for plant rDNA (ITS2). Specific primer pairs were designed to amplify DNA for the detection of one fruit species. Primer specificity was assessed with four fruit species. A mixture of fruit puree from the two fruits was used to determine the sensitivity of the multiplex PCR assay. Six commercial fruit products were evaluated to verify the applicability of the multiplex PCR assay. The methodology of molecular detection of fruit DNA by qPCR and multiplex qPCR (duplex) includes approaches, which enable to detect two fruits (strawberry-raspberry, apricot-apple) in one reaction and thus reduces time and money requirements.
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Isolation of compounds from Cannabis sativa and their anti-inflammatory effect
Baranová, Zuzana ; Vespalcová, Milena (referee) ; PharmDr.Daniela Veselá (advisor)
The object of this thesis is a traditional and also controversial plant Cannabis sativa. The theoretical part is focused on ubiquitous polyphenolic compounds – flavonoids, also present in the studied plant. All previously researched and confirmed effects on human body are described in detail. The experimental part of this thesis describes the isolation and identification of substances of the chloroform and hexane yields of extract obtained from this plant. Chromatographic methods were used for isolation – thin layer and column chromatography and semipreparative HPLC. Obtained substances were characterized using UV, IR spectrophotometry and NMR. Then the anti-inflammatory activity of obtained substances and also of the ethanolic extract and its yields was observed. The result of the experimental part was the isolation of one pure substance which was identified as the cannabidiolic acid. Using the THP 1 assay, we demonstrated mild anti-inflammatory effect of the non-polar yields and isolated CBDA.
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Study of antimicrobial substances of ginger
Ciburová, Alena ; Skoumalová, Petra (referee) ; Veselá, Mária (advisor)
For thousands of years ginger rhizomes are used in traditional Chinese medicine. Because of his significant pungent flavour is commonly used in foods and beverages all over the world. Nowadays many of the beneficial pharmacological positive effects of ginger rhizomes are identified. Their occurrence is due to the high concentration of bioactive compounds. This thesis is focused on analysing of occurrence of bioactive compounds such as polyphenols and flavonoids and their influence on antioxidation and antimicrobial properties of samples of fresh and dried ginger. The results show that for extraction of bioactive compounds in different ginger samples is more suitable to use different types of extraction solvents. The highest antioxidation activity was measured for macerate of 100% bio ginger tea from Sonnentor company in 96% ethanol. Antimicrobial properties were showed only for 100% bio ginger tea against gram-positive bacteria Microccocus luteus.
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Possibilities of identification of flavonoids in environmental matrixes
Magdechová, Andrea ; Zlámalová Gargošová, Helena (referee) ; Vávrová, Milada (advisor)
Inherent part of plants are active substances; flavonoids belong to this group. They are used in medicine, cosmetics and they shloud be a part of our diet because of their positive effects. This bachelor thesis is focused on the identification of flavonoids in selected types of coniferous trees and moss. Pines, firs and spruces were selected as the representants of coniferous trees, together with mosses Polytrichum formosum and Rhytidiadelphus subpinnatus. Flavonoids were isolated using liquid-liquid extraction and identified using thin layer chromatography and high-performance liquid chromatography.
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Changes in selected local fruits during freezing.
Matějková, Markéta ; Melounová, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on study of low-molecular antioxidants present in various kinds of fruits, namely berries. In theoretical part detailed characterization of antioxidants studied in presented work and their biological effects are introduced. Further, principals of processing and storage of specified species of fruits are discussed. Changes observed during storage of specific fruits are described too. In practical part changes in content of selected antioxidants in berries were followed. As studied material strawberries, raspberries, blueberries, red and black currants were used. All kind of these fruits was stored in fridge for six months using several different kind of processing. Berries were stored as whole fruits, whole osmotically processed fruits by sucrose, raw pulp and sweetened pulp. At first, starting values of selected antioxidant parameters were measured in fresh fruits (ascorbate, total antioxidant activity, total phenolics, catechins and individual flavonoids). After freezing the same parameters were measured regularly in two month periods. As the most suitable method of fruit processing, with regard to antioxidant content, storage of the whole fruits or pulp can be recommended. Content of ascorbate decreased in all forms and species of the processed fruits during all the time of storage. Oppositely, the content of other studied antioxidants exhibited fluctuations or increasing trend. Sensory analysis was proved for the whole fruits and also for whole sweetened fruits.
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Study of natural compounds of elderberry flowers
Pončíková, Alžbeta ; Skoumalová, Petra (referee) ; Veselá, Mária (advisor)
The aim of this bachelor thesis was to determine the concentration of bioactive substances such as polyphenols and flavonoids and also the total antioxidant capacity in extracts from flowers of elder. The second part was the subject of an experiment to determine the antimicrobial activity. The theoretical part deals with the description of individual bioactive substances, the description of the elder and the bacteria used. In the experimental part, aqueous extracts were prepared, in which total polyphenols, flavonoids and oxidizing activity were determined. The results of the determination of polyphenols and flavonoids show that in order to achieve a higher content of flavonoids and polyphenols, it is more appropriate to use the highest possible initial temperature for leaching the base flower. No significant differences were found when comparing the antioxidant activity of solutions from the average values. The extracts did not show significant antimicrobial activity.
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Isolation of antimicrobial compounds from spent coffee grounds
Kurzová, Pavlína ; Veselá, Mária (referee) ; Kovalčík, Adriána (advisor)
Coffee grounds are one of the very valuable lignocellulosic wastes that have been able to be processed and used for isolated phenolic substances. Many phenolic substances isolated from lignocellulosic wastes have antimicrobial properties. Aim of this thesis is isolation phenolic substances from spent coffee grounds extract and their available antimicrobial properties. Two isolation ways were applied to receive phenolic substances from spent coffee grounds: 1) solvent extraction (hexane, 75% ethanol, 70% acetone, diethyl ether, and ethyl acetate) and 2) release of active substances by alcoholic fermentation. All isolated materials were characterized by the viewpoint of concentration of reducing sugars, polyphenols and flavonoids. Subsequently, their antimicrobial activity was determined by using agar diffusion and broth dilution methods. Two gram-positive bacteria (Bacillus subtilis and Micrococcus luteus), one gram-negative bacteria (Serratia marcescens) and two yeasts (Candida glabrata and Saccharomyces cerevisiae) were used for antimicrobial testing. High-performance liquid chromatography (HPLC) was used to identify phenolic substances in the extracts. First, the results showed that the isolated sample with the highest antimicrobial activity was 70% acetone extract. This extract contained chlorogenic acid, gallic acid, caffeic acid and coumaric acid according to HPLC. The ethyl acetate extract showed the lowest antimicrobial activity. Second, after lyophilization, the isolated materials also revealed high antimicrobial activity. The highest antimicrobial activity displayed the materials obtained by the extraction with 70% ethanol. This sample contained chlorogenic acid, gallic acid and caffeic acids. Next, samples with phenolic compounds were obtained by the alcoholic fermentation of spent coffee grounds. These samples showed similarly to the previous solution extracts significant antimicrobial activity. Interestingly, the unfiltered samples received directly after alcoholic fermentation also showed antifungal properties. The characterization of phenolic compounds by HPLC showed similarly as in previous examples that chlorogenic, caffeic and gallic acids were present in these samples.
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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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Study of properties and effect of some natural antimicrobial substances
Horňáková, Nikola ; Kostovová, Iveta (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on the testing of natural antimicrobial substances of plant origin, dealing with their characterisation, their effect against the microorganisms, optimization of antimicrobial testing and increasing of efficiency of their active compounds. Theoretical part of this thesis describes a characterisation of used natural species, their important properties, spectrophotometrical methods applied in determination of active compounds, opportunities of stabilization of natural substances and various techniques of antimicrobial testing. In experimental part 8 kinds of tea and non-tea plants (Pai Mu Tan, Formosa Gunpowder, Gunpowder Black, Honeybush, Lapacho, Aspalathus linearis and Paullinia cupana) were used and combined with 6 herbal species (Syzygium aromaticum, Urtica dioica, Hippophae rhamnoides, Matricaria recutita, Plantago lanceolata and cinnamon), extracted by different solvents (water, ethanol and dimethyl sulfoxide). In these extracts amount of antioxidants and effect to three bacterial cultures (Escherichia coli, Micrococcus luteus and Serratia marcescens) were determined. To improve antimicrobial, antioxidant activity and stability aqueous tea extracts were encapsulated into liposomal particles.
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