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Modern Approaches in Qualitative Aspects of Foods Assessment
Tobolková, Blanka ; Omelka, Ladislav (referee) ; Rapta, Peter (referee) ; Buňka, František (referee) ; Polovka, Martin (advisor)
Antioxidant properties and some other characteristics of selected organic and conventional products (wine, spelt flours) were evaluated in view of their potential utilization as markers suitable for food unambiguous differentiation according to the affiliation to production system. Beside these, study of fruit juices stability during storage in dependence on different technological procedures of juice processing was performed. In both cases, combination of dominantly EPR and UV/VIS spectroscopy but also other methods (e.g., HPLC, AAS, electrophoresis) was applied to evaluate the stability and antioxidant properties of selected samples. Statistical methods, especially methods of multivariate statistics were used to assess the influence of production and technological-processing operations on antioxidant status of foods and their selected characteristics. Qualitative analysis of Slovak and foreign organic and conventional wines proved that their antioxidant properties are influenced by production system, vintage and variety. On the basis of statistical analysis, descriptors of AAE, kTEMPOL and %RS were selected as the most powerful markers for Slovak organic and conventional wines discrimination. The discrimination of white and red organic and conventional wines possessed 100% and 95.2% correctness, respectively. High correctness of differentiation of Slovak and foreign wines was also achieved. Monitored descriptors of antioxidant activity of spelt flours varied in dependence on season, origin, variety, production system and depend also on way of spelt treatment, although this effect is not so significant. It was also confirmed that the type of extraction agent substantially affects the composition of extracts including polyphenols and flavonoids concentration, affecting thus also their antioxidant activity. Mixture of 50% ethanol/water was selected as the most promising extraction system. Although the results of individual spectroscopic assays revealed high variability and often ambiguous trends, the differences found were sufficient for successful differentiation of both wines and spelt flour samples according to the selected criteria by multivariate statistical processing of the data. Influence of changes in technological procedures of fruit juice processing (nitrogen atmosphere application, utilization of caps with oxygen scavengers) on radical-scavenging properties of 100% pineapples juices with pieces of pineapple and 100% orange juices with pulp was assessed as well. Results obtained proved that antioxidant activity of juices varied in dependence on storage conditions (temperature, storage time, light exposure) and depends also on origin, variety and quality of fruit used. However, the application of nitrogen atmosphere and active packaging materials is not sufficient enough to eliminate the oxidation reactions in juices, but changes in antioxidant activity are better predictable. It can be concluded that EPR spectroscopy could be effectively applied for wines and spelt flours differentiation according to the way of production and to assess the stability of food products, either alone or in combination of UV/VIS spectroscopy and the other methods, utilizing multivariate statistics for processing of experimental data.
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HPLC evaluation of select drugs V.
Kašková, Jana ; Mokrý, Milan (advisor) ; Sochor, Jaroslav (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Drug Control Candidate: Jana Kašková Consultant: RNDr. Milan Mokrý, CSc. Title of Thesis: HPLC evaluation of some drugs V. This thesis is about looking for the optimal conditions for simultaneous HPLC analysis in combined tablets of amlodipin and atorvastatin with subsequent determination of their content. As the most suitable stacionary phase was chosen chromatographic column 125x4 mm I. D. contains Nucleosil 120-5 C 18, Macherey-Nagel, and the mobile phase formed by mixture of acetonitrile - disodium hydrogen phosphate dodecahydrate solution (0,025 mol/l) in the ratio 55:45, acidified with phosporic acid at pH 4,4 at a flow rate of 1,0 ml/min and temperature 25řC. Propylparaben was used as the most suitable internal standard. The detection was performed at 210 nm using an UV-VIS detector. At the determination of content of medicaments in tablets was found that used compounds were eluted in following order: propylparaben, atorvastatin and amlodipine besylate.
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Isolation and characterisation of light harvesting complexes from bacteria of the genus Gemmatimonas
DACHEV, Marko
Photosynthetic bacteria are highly abundant. The isolation and characterization of the light-harvesting complex from the Gemmatimonas phototrophica AP64T which belongs to the seventh phylum of the evolutionary important (bacterio)chlorophyll-containing bacteria are reported here. The purification of the complex was achieved by gel-filtration and electrophoresis. HPLC was used for identification of the pigments. The protein subunits were further identified by MS analysis.
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Analysis of drinks sweetened with stevia extracts
Procházka, Václav ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
The steviolglycosides are the natural, sweet substances from Stevia rebaudiana Bertoni. It affect human health positively and its sweetness is 300x stronger than the sweetness of sucrose. That's why it's used to sweetening the commercial products. Because of its potential properties it's good to have an appropriate method to isolate it. High performance liquid chromatography ( HPLC) is based on the separation of analyte between two immiscible phases with high pressure pump and appropriately chosen stationary phase in the column. Than the analytes come out from the column in different retention times. This master´s thesis follows up selection of the best HPLC system for isolation of the main steviolglycosides and its analysis in commercial products. In the theoretical part of the thesis is described the origin, basic characteristics, botanical description, cultivation and affect to the human health of Stevia rebaudiana Bertoni and its use in food industry. There are also concisely characterized the sweet substances contained in the plant, so called steviolglycosides. Than there are given the theoretical basics of high performance liquid chromatography, HPLC instrumentation and its specific applications at sleviolglycosides with the basic chromatographic parameters. The object of the first experimental part was to research the optimum conditions for time and separation effective chromatographic analysis and select the best chromatographic system for isolation of steviolglycosides. In the second experimental part, I have compared and defined the main steviolglycosides (stevioside, rebaudioside A) in nine selected products, commercially available in Czech republic, with the best chromatographic method. In these products was the contain of the stevioside or rebaudioside A confirmed or refused.
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Monitoring flavonoidních látek a karotenoidů ve vybraných doplňcích stravy
Hynštová, Veronika
Dietary food supplements are among the most rapidly growing sectors in the food product industry. The majority of consumers trust in the safety and efficacy of these products. For these reasons is a quality control required and analytical methodologies for this must be used. For identification and quantitative analysis four flavonoids diosmin, hesperidin, rutin and troxerutin in food supplements was used HPLC/MS method. For identification and quantitative analysis three carotenoids betacarotene, lutein and zeaxanthin in food supplements was used HPLC/UV/ViS/DAD method. Separation of flavonoids was achieved on the column ZORBAX POROSHELL 120 EC-C18 (50 x 4,6 mm, 2,7 um) and separation of carotenoids on the column ZORBAX SB CN (75 x 4,6 mm, 3,5 um). The amount of flavonoids and carotenoids in tablets and capsules was determined altogether in 12 different commercial preparations.
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Analysis of selected nutritional parameters in the new varieties of gooseberries
Nováková, Jana ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
Diploma thesis deals with the new varieties of gooseberries. The theoretical part characterizes gooseberry from a biological point of view, what is the content of healthful nutrients and states food technology aspects. Furthermore, the theoretical part deals with the main parameters examined nutrition: vitamin C, anthokyanům and antioxidant activity. In the experimental part was measured both weight solids content and soluble solids. Vitamin C was measured by HPLC, anthocyanins using a pH differential method and for antioxidant activity determination was selected method by Kanedy known also as DPPH.
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Application of Separation Techniques Connected with Mass Spectrometry for the Analysis of Environmentally Important Compounds
Mácová, Daniela ; Čelechovská, Olga (referee) ; Márová, Ivana (referee) ; Demnerová, Kateřina (referee) ; Čáslavský, Josef (advisor)
The identification of the hydrolysis and photodegradation products of flexible polyurethane foams (PUFs) with addition of biooriginated and biodegradable additive was the first topic of this dissertation work. Separation of polyurethane foam hydrolysis degradation products, designed for ecotoxicological tests, was managed by high-performance liquid chromatography coupled with mass spectrometry (HPLC/MS). The degradations product structure was elucidated by tandem mass spectrometry (MSn). PUF photodegradation products were obtained by exposure of materials by irradiation at 254 nm. Semi-volatile degradation products were isolated from the exposed polyurethane by n-hexane extraction; volatile compounds were collected by solid phase microextraction (SPME). Gas chromatography with mass spectrometry (GC/MS) and complete orthogonal tandem gas chromatography with mass spectrometry (GCxGC/TOF MS) was used for separation and identification of photodegradation products. The influence of the bio-filler on the character of degradation products and the possible effect of PUF degradation products on the environment was discussed at the end of this section. The determination of isoprostanes – markers of oxidative stress in tissues of beadlet anemone (Actinia equina) was the subject of the second topic. F2-isoprostanes were synthesized from the arachidonic acid. With thereby prepared isoprostanes the method of determination by liquid chromatography with tandem mass spectrometry (HPLC/MS/MS) was developed and optimized. The isoprostane isolation process from the Actinia equina tissues was optimized with solid phase extraction (SPE). The resulting methodology was used to quantify isoprostanes in tissues of anemones, which were exposed to both moderate and high temperature changes. The temperature changes were used to initiate the oxidative stress in organisms. In addition, concentration levels of unknown compounds were also monitored. These unknown compounds were extracted from tissues together with F2-isoprostanes and their identity is discussed in this dissertation work too. The possibility of using isoprostane levels in the Anthozoa tissues for the oxidative stress monitoring is discussed in the conclusion of this work.
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Production of extracellular polymeric substances by Aureobasidium pullulans
Horáček, Pavel ; Breierová, Emília (referee) ; Márová, Ivana (advisor)
The diploma thesis is focused on the study of the influence of cultivation conditions and arrangement for the production of extracellular polymeric substances by using yeast-like microorganism Aureobasidium pullulans. In the theoretical part a brief description of A. pullulans, its use in biotechnology and produced exobiopolymers, especially pullulan and poly-L-malic acid are presented. The first aim of the experimental part was to set the most appropriate cultivation conditions for A. pullulans CCM 8182. Growth and production properties in optimum conditions were compared with cultivation on waste substrates - oat bran, buckwheat husks, apple fiber and others. Waste substrates can be used as cheap nutrient sources which enable reducing cost of potential biotechnological production. As a further part of this work, optimization of HPLC/RI method for analysis of exobiopolymers has been done. Optimal mobile phase composition and chromatography conditions were proposed. Column Roa organic acid H+ was the most suitable for simultaneous separartion of glucose and malic acid. Before HPLC analysis hydrolysis of polymers was done. Sulphuric acid (5 mmol/L) was used as a mobile phase at flow rate 0.5 mL/min and temperature 60 °C. The highest production of pullulan occurred using oat bran as a substarate (13.03 g/L) at an initial pH 7.5. Maximum production of poly-L-malic acid was observed during the cultivation on apple peels (2.89 g/L) at pH 6. It was found that the higher production of poly-L-malic acid occurred at pH 6, while higher production of pullulan was at pH 7.5.
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Determination of different forms of casein in milk
Kaňková, Veronika ; Hejtmánková, Alena (advisor) ; Markéta, Markéta (referee)
Casein proteins are important escpecially for cheese making. In addition to technology and other factors, casein concentration in milk and relative representation of individual casein fractions influence cheese yield. Majority fractions are alfa-casein, beta-casein and kappa-casein. For the determination of proteins in the milk can be used electrophoretic techniques or near infra-red spektrometry. High performance liquid chromatography (HPLC) is going to be used. HPLC is widely used analytical method, which is based on differential affinity of the substances to the mobile and the stationary phase.
The thesis has introduced the method of determining the casein fractions by HPLC. The method was partially optimized using cow milk and calibrated to the standard solutions, which were purchased casein fractions derived from the bovine milk. Real samples of cow, sheep and goat milk were analyzed. The goat milk was available in several variants: Sanski goat milk and white shorthair goat from domestic or farm breeding. All milk samples were analyzed for casein and casein fractions proportions. Chromatograms show that the casein formula is different in cow, sheep and goat milk. Different concentrations of the casein fraction in the milk of various animal species have been statistically detected in almost all cases. The exception was the concentration of beta-casein in the milk of white shorthair goat from the domestic and the farm breeding and cow milk. In these types of milk there was no statistically significant difference in the concentration of beta-casein. Analysis of individual samples of white shorthair goat milk from the farm breeding shown that casein content in the milk of different animals reared under the same conditions may be different. Ratios of beta-casein to alfa-casein, beta-casein to kappa-casein and alfa-casein to kappa-casein were evaluated in all samples. Interspecific comparisons proved that ratios were statistically significantly different in all milks. In the milk of Sanski goat, there was found the stable ratio of beta-casein to alfa-casein during lactation. For all goat milk there were typical higher values of the ratio of beta-casein to kappa-casein. The ratio of alfa-casein to kappa-casein was highest in the sheep milk. Despite some shortcomings, it is possible to use the HPLC method possible for these purposes, but it is necessary to continue with its optimization.
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Methods for Elemental Speciation of Arsenic Compounds.
Navrátilová, Jana ; Jarošová, Alžběta (referee) ; Golian,, Jozef (referee) ; Šimko, Peter (advisor)
Speciační analýza arsenu v různých matricích s využitím HPLC/ICPMS byla předmětem této práce. Toxicita arsenu závisí na oxidačním stavu a formě, ve které je přítomen. Znalost zastoupení specií arsenu je nutná k hodnocení toxicity a biodostupnosti. Obecně, anorganické specie jsou více toxické než organické. V práci byla studována degradace arsenocukrů v mořských řasách za simulovaných přirodních podmínek. Původní arsenocukry byly transformovány na arseničnan a kyselinu dimethylarseničnou. Arsen vstupuje do rostlin z půdy a vody a následně může vstoupit do potravního řetězce. S ohledem na tuto skutečnost byla speciační analýza provedena u vybraných vzorcích rýže, zakoupených v české obchodní síti. Stanovený celkový obsah arsenu se pohyboval v rozmezí 36.06 µg/kg - 218.11 µg/kg a hlavními speciemi byla kyselina dimethylarseničná a anorganický arsen (54-78%). Mořské ryby a tuky obsahují významnou část arsenu ve formě zvané arsenolipidy. Část práce byla zaměřena na analýzu arsenolipidů u máslové ryby (Lepidocybium flavobrunnrum) s celkovým obsahem arsenu 1.8 mg/kg a 22% celkového arsenu bylo vyextrahováno pomocí hexanu, což potvrzuje lipofilni charakter těchto sloučenin. Hlavní specií stanovenou ve vodném extraktu byl arsenobetain, představující 89%.
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