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Analysis of flavonoids in beer by LC-MS
Měřínská, Radana ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
Presented diploma thesis is focused on analysis of phenolic compounds in various types of beers. The aim of this work was to find possible differences among several types of beers and also between Czech beers and beers of foreign production. Theoretical part contains detailed description of beer technology, review of important analytical methods for determination of phenolic compounds and total antioxidant activity. The main attention is focused on instrumental technique LC/MS. In the experimental part values of total phenolics and total flavonoids and results of antioxidant status in analyzed beers were determined spectrophotometrically. Basic brewing characteristics were determined by pycnometry. On-line liquid chromatography with photo diode array detection and mass spectrometry detection was used for identification and quantification of individual phenolic compounds. Spectrophotometric analysis of phenolic and flavonoid levels seems to be less specific, that is consistent with findings in accessible literature. It was proved, that iso- bitter compounds exhibit about 65.44 – 90.93 % of the total bitter substances. These components are responsible for the main part of beer bitterness. The HPLC/PDA/ESI-MS was necessary to use for determination of characteristic phenolic compounds in individual types of beer. Within our measurement three columns were tested, the most favourable results were obtained using the column Restek C18. When compared with foreing beers, in Czech beers higher level of majority of phenolic compounds was detected and specific distribution of individual derivatives was found as well.
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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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Preparation and use of selected nanoparticles in cosmetics
Hoová, Julie ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
The Bachelor thesis is focused on preparation and use of selected nanoparticles in cosmetics. The theoretical part deals with general characterization and use of caffeine, phenolics and vitamin C in cosmetics. Further, characterization of liposomes and possibilities of encapsulation of active substances gained from natural sources were introduced. In experimental part liposomes with encapsulated active substances were prepared by three different techniques. Encapsulation efficiency was determined by HPLC/PDA, phenolics spectrophotometrically and vitamin C by titration. Prepared particles were monitored for size and stability by dynamic light scattering. Furthermore, long-term stability of liposomes in model conditions was evaluated as the amount of the active substances released during incubation. In this work was found out that from all tested samples co-encapsulated liposomes are probably the best application form which can be used in face lotion or gel. Co-encapsulated liposomes exhibited relatively high encapsulation efficiency, good stability and thanks to quality of active substances they meet customer’s requirements of cosmetic industry.
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Determination of basic chemical characteristics of blueberry pulp
Strapcová, Zuzana ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the investigation of selected chemical characteristics in the semifinished products of blueberries (Vaccinium myrtillus L.) and blueberries high (Vaccinium corymbosum L.). The theoretical part is described the botanical characteristics of both blueberries. The use of fruits is described in the next part. A description of the determination of the selected characteristic, refractometric of sugar dry mater, is described at the end of the theoretical part. In the experimental part, chemical characteristics were determined as total and soluble solids, pH, amount of titratable acids, reducing carbohydrates, phenolics and total anthocyanins in juice, pulp and extracts of blueberries. The purpose of the extracts was to find out how many total anthocyanins and phenolics are found in the skin of the fruit and which extract gives the highest yields. The results of the characteristics were compared across the wholefruit and semifinished products of the both blueberries. A mixture of water and ethanol in a ratio 50:50 was the most suitable solvent. The maximum extraction dependence was at twelfth and thirteenth hours of maceration. The maximum extraction dependence was determined by the above described chemical characteristics. Content of anthocyanin dyes expressed as delphinidin-3-glucoside was determined in extract of blueberry in 59,7 mg DGE100 g-1 and blueberries high in 19,6 mg DGE100 g-1. Total phenolics content expressed as gallic acid was determined in extract of blueberry in 890,9 mg GAE100 g-1 and blueberries high in 249,9 mg GAE100 g-1.
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Use of LC/MS technique to analysis of some physiologically active natural compounds
Trčková, Marie ; Čáslavský, Josef (referee) ; Kočí, Radka (advisor)
Presented work is focused on application of combined instrumental method RP-HPLC/ESI-MS in analysis of several groups of natural compounds with positive physiological activities. Especially some antioxidants were studied in commonly and abundantly consumed food. Moreover some other substances than standard compounds were observed in complex dies. In conclusion the HPLC/ESI-MS method is comparatively advantageous in phenolic analysis, while another type of ionisation would be used in case of carotenoid compound.
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Study of phenolic compounds in some biologic materials using method LC/MS
Měřínská, Radana ; Zemanová, Jana (referee) ; Kočí, Radka (advisor)
Presented bachelor thesis was focused on suitable methods for analysis of phenolics, especially modern instrumental methods were studied. In experimental part some standard phenolic compounds were analysed using combined technique HPLC/ESI-MS with off-line and/or on-line detection. Mass spectra of individual stadards and/or mixtures were determined in MS full scan and/or MS/MS full scan mode. Ionisation of chosen standard compounds was done in pozitive and/or negative mode. Parent ions of followed compounds were identified: reserpine (PI 609.9, NI 607.7), acid chlorogenic (NI 353), quercetin (PI 303.5, NI 301.5), rutin (PI 611, NI 609), morin (PI 303.1, NI 301.1). Typical fragments of studied standards were produced using MS/MS full scan mode. By fragmentation characteristic product ions were identified: acid chlorogenic (NI 191), quercetin (PI: 229.1 and 257.1; NI: 179.0 and 151.0), rutin (in MS/MS NI: 301; in MS3 NI: 179, 151.1), morin (PI: 285.1 a 257.1; NI: 283.2, 273.2, 257.1, 229.1). Optimal conditions of phenolic HPLC separation were determined including gradient elution and Restek column use. In conclusion on-line HPLC/MS detection using negative ionization was observed as the best configuration for phenolic analysis.
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Determination of some nutrition factors in selected kinds of fruit
Smělá, Margita ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
Diploma thesis is concerned with determination of some nutrion factors and vitamin C in various cultivars of apples (Pirus Malus, L.) and quinces (Cydonia oblonga, Mill.). In theoretical part there are described general characterization in selected kinds of fruits, their medically significant sunstances and utilization of these fruits. Main focus is paid to vitamin C. There are described its chemical properties and effect for human health. Various methods for determination of some nutrion factors with focus on determination of vitamin C by high-performance liquid chromatography. In experimental part, total of 27 various cultivars of aplles and 16 various cultivars of quinces were analyzed. These cultivars are from grower station Faculty of garden of Mendel university. For determitation vitamin C was used by high-performance liquid chromatography. Vitamin C was determination as an ascorbic acid. Some nutrion factors were analyzed in experimental part. There were analyzed dry matter, total flavonoids, total phenolics and titratable acid in various cultivars of apples and quinces. There were compared of some various cultivars after representation and content of significant substances as result. The last part of thesis was sensory analysis of apples.
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Basic chemical properties of fruits of selected cherry varieties
Chmil, Vojtěch ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
Diploma thesis is focused on chemical characteristics of nine selected sweet cherry varieties in nine parameters. Total and soluble solids were analyzed with these results 13.07–16.58 % for total and 14.67–19.50 °Brix for soluble solids, ash content 0,31–0,39 %, titratable acidity 5.44–9.91 g of malic acid per 1 kg of fresh cherries and formol number 14.45–23.73 ml of 0.1 M NaOH per 100 g of cherries. Then there were analyzed crude proteins content calculated from total nitrogen content determined by Kjeldahl method with results 0.41–0.68 % of crude proteins. Molecular absorption UV/VIS spectrophotometry was used for determination of total phenolic substances 0.30–0.89 g of gallic acid per 1 kg of cherries and total content of anthocyanins 128–848 mg of cyanidine-3-glucoside in 1 kg of cherries. Saccharides were determined by high performance liquid chromatography (HPLC) with ELSD detector. Content of glucose was 45.45–59.49 g/kg and fructose 46.88–60.01 g/kg. All results are compiled using tables and graphs and discussed. Experimental part of the thesis also describes principles and procedures of every analysis, so it can be reproduced. In theoretical part there is described botanical characteristic of cherry tree (Prunus avium L.), active substances contained in its fruits and their use in food industry. At the end of the theoretical part there is described instrumentation of high-performance liquid chromatography.
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Study some active substances in Czech beer
Pařilová, Kateřina ; Vávrová, Milada (referee) ; Márová, Ivana (advisor)
The aim of this work was to study phenolics and other active compounds in 22 kinds of lager beer and especially to find some differences between Czech beer and beers made in foreign countries. In theoretical part the most useful methods for phenolic and protein analysis are discussed. Further, basic steps of brewery technology are introduced and main beer components with regard to Czech beer specificity are presented. Analysis of total phenolics, total flavonoids, antioxidant activity and most of basic technological characteristics was performed spectrophotometrically. To identification and quantitative analysis of individual phenolics on-line liquid chromatography with photo-diode array (PDA) and mass spectrometry (MS) detection was used. Protein analysis was performed by vertical electrophoresis SDS-PAGE and by Experion microfluidic electrophoresis (BioRad). From the total of 22 samples, 15 Czech beers and 7 beers of foreign marks were enrolled into this study. In these samples levels of brewery characteristics, group antioxidants and individual phenolics were compared. Flask and can beers as well as alcoholic and non-alcoholic beers were compared too. As a model comparative sample the Czech hop of Sládek variety was used. Finally, usefulness of tested parameters to differentiation composition and technology of individual beer samples was evaluated and parameters suitable for Czech beer authenticity analysis were proposed.
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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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