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Pressurized solvent extraction of plant material for food industry use
Holasová, Petra ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
Flavonoids were identified and quantified in samples of dry leaves of plant Stevia rebaudiana Bertoni. Content of flavonols (kaempherol, quercetin, myricetin, rutin) and flavons (apigenin, luteolin) were compared in three samples (standard leaves of Stevia rebaudiana Bertoni, Stevia rebaudiana Bertoni origin from Ukraine and from Czech republic), that were extracted by three extraction methods (PSE, ultrasonic extraction, Soxhlet extraction) with two polar solvents, methanol and ethanol, in combination with non-polar hexane. Extracts were analyzed by HPLC with detection UV-VIS. Antioxidant activity and total content of flavonoids in extracts were measured by spectrometry. Stable free radical DPPH. was used for determination of scavenging effect in extracts. PSE was the most effective extraction method with this conditions – 120 °C, dynamic mode and with methanol like solvent.
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Determination of total antioxidation activity of tea pickles in selected sorts of tea
Bartošová, Jitka ; Vitoulová, Eva (referee) ; RNDr.Jana Skopalová, Ph.D. (advisor)
This thesis deals with the total antioxidant activity (TAA) evaluation of various sorts of tea (green, black, half-fermented, white, mate, rooibos and herbal) depending on the process and time of their treatment. The main emphasis is put on testing a new method of measuring the total antioxidant activity by flow coulometry. The results acquired by this method are compared to the results of the chemiluminescent Trolox equivalent antioxidant capacity (TEAC) method which is a standard for measuring the total antioxidant capacity in various materials and raw materials. The work discusses the reasons for the differences in the values found by both methods.
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Preparation of some application formula of antimicrobial substances
Krempaský, Kamil ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
The main aim of this study is to determine antimicrobial activity of herbal extracts and also encapsulate these extracts and lysozyme to liposomes. The extracts were prepared from above ground part of wormwood (Artemisia absinthium), aerial part of breckland thyme (Thymus serpyllum), the root of purple coneflower (Echinacea purpurea), liquorice (Glycyrrhiza glabra), corolla of pot marigold (Calendula officinalis) and berries of sea buckthorn (Hippophae rhamnoides). In all extracts antioxidant activity and the amount of total polyphenols and flavonoids was determined. All of these extracts and also lysozyme were used for encapsulation to liposomes. Prepared liposomes were then tested for their stability. Further, encapsulated as well as free extracts were tested for their antimicrobial activity on Escherichia coli, Serratia marcescens, Micrococcus luteus and Bacillus subtilis. Extract from Echinacea purpurea showed the highest antimicrobial activity.
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Analysis of active substances in honey
Jelénková, Zuzana ; Kubešová,, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on biologically active compounds determination. 26 samples of honey, one sample of propolis and one sample of royal jelly were analyzed. Honey were harvested in year 2006 and 2007 and bought in retail chain, special shops and directly from bee-keeper. Samples were analyzed by titration, spectrofotometry, LC/MS and RP-HPLC methods. The study was focused on analysis of antioxidants. Followed groups of antioxidants were determined: flavonoids, catechins, carotenoids, vitamins E, C, A. Authenticity of quality was determined by hydroxymethylfurfural analysis. Average values of total antioxidant capacity ranged (12.75-137.49) mmol .100 g-1. Average values of total phenolic ranged (8.51-61.34) mg .100 g-1 and average values of total flavonoids ranged (0.75-6.04) mg .100 g-1. Honey samples contained (41.83-585.10) g .100 g-1 of rutin, (9.30-313.40) g .100 g-1 of myricetin, (6.5-171.90) g .100 g-1 of luteolin, (3.19-436.37) g .100 g-1 of quercetin, (2.10-242.66) g .100 g-1 of apigenin, (0.15-105.12) g .100 g-1 of caempferol and (0.07-17.52) mg .100 g-1 of naringenin. From group of catechins there were measured (5.98-310) g .100 g-1 of catechin, (17.77-486.29) g .100 g-1 of epicatechin, (0.18-64.90) g .100 g-1 of catechin gallate and (0.59-140.56) g .100 g-1 of epicatechin gallate. From lipophilic compounds the most abundant in honey samples was tocopherol, its value ranged (29.20-8531.17) g .100 g-1. Content of ascorbic acid ranged (0.65-4.65) mg .100 g-1. Content of hydroxymethyl.furfural. ranged (0.26-4.06) mg .100 g-1. By LC/MS method luteolin, naringenin, protocatechin acid, coffee acid and p-cumaric acid in honeydew were detected and, furthermore, kyanidin and pinocembrin in floral honey were found. Mono-floral honey contained biologically active compounds the most, imperceptibly less contained multi-floral honey and honeydew honey. Acacia honey contained the lowest amount of biologically active compounds.
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Preparation and stability of core-shell type organic micro- and nanoparticles
Byrtusová, Dana ; Benešová, Pavla (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on possibilities of encapsulation polyphenolic compounds in core-shell type organic micro- and nanoparticles. The theoretical part is aimed at characterization of polyphenolic compounds, their biological effects and their possibilities of encapsulation into various types of particles. The experimental part deals with the content of polyphenolic compounds, flavonoids and anthocyanins in guarana, ginseng ang goji. Extracts from these samples were packed into liposomes and polysaccharide particles. Encapsulation´s effectiveness was determined spectrophotometrically. The stability of particles was monitored for size and stability by dynamic light scattering. The particles were exposed to the model body fluids and model food.
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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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Possibility of determination of selected flavonoides
Smělá, Margita ; Vitoulová, Eva (referee) ; Vespalcová, Milena (advisor)
The theoretic part of the bachelor‘s thesis deals with description of selected flavonoids as apigenin, quercetin, luteolin, keampferol, rutin, myricetin and with options of their determinations. There were described typical properities and effects of several flavonoids at first. In the next part there are principles of methods, especially high-performance liquid chromatography and capillary electrophoresis. The biggest attention was made to literary survey of determination flavonoids coumpounds mentioned above, by high-performance liquid chromatography and capillary electroproresis. There were described the collection of plant material for extraction of flavonids in the practical part. The white and blue grapes were frozen by dry ice as soon as they were separated from a busch. Grapes were made in a nitrogenous atmosphere and lyophilizated after the frozen.
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The stability of biologically active compounds in elderberry (Sambucus nigra L.) inflorescence during processing
SUCHÁ, Renata
This thesis examines the stability of rutin in the inflorescences of the elder during processing. Elder (Sambucus nigra L.) is a medicinal plant that was used for medical purposes as early as in the Middle Ages. Both flowers (Flos Sambuci) and fruit (Fructus Sambuci) of the elder are on the list of official medicinal products of the State Institute for Drug Control. The main active phenolic substance is flavonoid rutin. Flavonoids are phenolic substances of plant origin. Among the best known properties of these substances is their antioxidant activity. They protect the low density blood lipoproteins from the oxidation modifications that cause the development of arteriosclerosis and hypertension. As a medical plant, the elder is used especially for the preparation of a medicinal drink. It is also commonly used as a material for the preparation of syrup. This product serves as a basis for a refreshing and tasty drink and lately is has also started to be sold in shops. For comparison, five single-flower syrups from the elderflower by different producers were bought. A method of preparation of the elderflower syrup was devised, based in one case on frozen elder inflorescences and in the other on dried inflorescences. The plant material came from wildly growing shrubs and it was collected in June 2013. Altogether, 8 syrups were prepared in the laboratory, 4 of them from fresh material and 4 from dried material. Two different methods were used. The first one was based on extraction using sugar solution, the second one on extraction using water solution where sugar was added afterwards. Another added substance was ethanol. The method for measuring the amount of rutin in the samples was a combination of two extraction steps. The first step was the usual exraction using aqueous methanol and the second step was extraction using a solid sorbent (SPE). The analysis of fresh and dried material concluded that dried elderflowers contain many times more rutin than fresh elder. Among the commercially produced syrups, the "Kitl Syrob Bezový" contained most rutin; a little less rutin was found in "Hamé Bylinný sirup Bezový květ". The concentration of rutin in the syrups prepared in the laboratory was much higher than in the commercial products. By using different methods of syrup preparation and their subsequent analysis, it was found that the syrups prepared from the dried inflorescences contained a higher amount of rutin than the syrups produced in the same way, but from frozen material. Addition of a small amount of ethanol had no effect on extraction of rutin from inflorescences. Free quercetin, which indicate a decomposition of rutin, wasn´t found in any of produced syrups. The produced syrups were used for the preparation of a drink and then underwent sensory analysis. The paired two-sided preference test included pairs of drinks consisting of a fresh elder drink and dried elder drink. The results showed that the evaluators preferred syrups from dried elderflowers in two of the cases, while in the other two evaluated pairs, the results were not statistically significant. In all cases, the evaluators most often found small and middle differences. The gained results show that the best method of syrup preparation uses dried plant material and sucrose solution as the extraction agent. The syrup prepared in this way contained most rutin and at the same time showed the smallest losses of this substance, which is beneficial to human health. Furthermore, it also tasted better in comparison with syrup prepared in the same way, but from fresh material.
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The proposal of vinegar farm with the character of functional foods.
HRDINOVÁ, Vendula
The work is focused on the development of a new functional food . The functional food in addition to nutrient sources must clearly contribute to the health improvement thanks to another ingredient which must be of natural origin. I chose vinegar as the basic component in my work. The vinegar can be made in a vinegar manufacturer through classical oxidation technique of diluted ethanol solution by acetic bacteria on the large contact surface with air alcohol analysis . Diluted ethanol may well serve as alcohol analysis, but I used some weak cider. I prepared the cider from alcoholic fermentation of apple pulp waste extraction after its pressing. The cider was pressed together with water. Red onion extracts, as a rich source of flavonoids, work as metraceutikum and give this vinegar the
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Leaf vegetable as a source of phenolic compounds with nutritional value.
TRÖSTLOVÁ, Daniela
The present work treats the amount of phenolic substances in salad plants. A part of this vast plant group is made of flavonoids, which are important by their accessibility and significant biological activity. Quercetin and rutin are in the main focus of this work. They are noted for their favourable biological effects. Having antioxidant qualities, they prevent and stop the lipid peroxidation and they dispose of free radicals. Flavonoids are used in medicine and can prevent the formation of chronic diseases, such as cardiovascular disease or atherosclerosis. The amount of phenolic substances in the chosen sample of ten salad plants was determined by means of micellar electrokinetic capillary chromatography (MECC) and by high-performance liquid chromatography (HPLC). We have used a freeze-dried material for the analysis. The utmost amount of quercetin was found in lettuce grown on outside garden. 48 600 mg/kg of dry matter highly exceeded the amount of quercetin in other plants. There were other phenolic substancs as well: rosmarinic acid, caffeoylchinol acid and caffeic acid. Among others, we found derivatives and colourants of caffeic acid as well.
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