National Repository of Grey Literature 277 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Solubilization of water-insoluble vitamins into vesicular systems based on ionic amphiphilic pairs
Kolomá, Nikola ; Mravcová, Ludmila (referee) ; Mravec, Filip (advisor)
This thesis deals with the characterization and preparation of catanionic vesicular systems and their interaction with water-insoluble vitamins. Catanionic vesicles systems was prepared from two differently charged sufractants CTAB and SDS in formation ion pair amphiphile. Stability of vesicles was secured by adding cholesterol with positively charged surfactant DODAC. Were selected vitamin A and vitamin E for solubilization into these vesicles. The next part of this work was focused on determining the efficiency of incorporation these vitamins into the HTMA-DS vesicular system. The characterization of these systems was improved by measurement on a UV-VIS spectrometer, DLS and by HPLC with UV-VIS detector. During measurement by UV-VIS and HPLC the efficiency of solubilization of vitamin A and vitamin E into vesicles was determinated. In both cases higher efficiency was determinated for vesicles with incorporated vitamin A. Higher efficiency for both vitamins was determinated by HPLC. The reason is probably the higher sensitivity of the metod, work in labs with dark glass and preparing individuals samples into vials, which were inserted into the device for individual dosing by injector. The work serves primary evaluation results in view of the vesicular system for use in pharmaceutical application like carrier non-polar vitamins.
Determination of selected red fruit species in plant-based food using multiplex PCR and instrumental methods
Vybíralová, Natálie ; Langová, Denisa (referee) ; Fialová, Lenka (advisor)
In many cases food is becoming the subject of adulteration, including fruit products that contain raspberries, strawberries and blueberries. This bachelor thesis is focused on the detection of strawberries, rapsberries and blueberries in model and commercial baby food products using multiplex PCR and HLPC. The theoretical part of this thesis is focused on composition of red fruits, their importance in human nutrition and especially about isolation of DNA from plant material. The aim of the experimental part of work was the analysis of selected commercial and model mixtures fruit purees containg raspeberries, strawberries and blueberries using instrumental and molecular biological methods. The results of these metods are compared. Commercial purees were bought in retail grocery shop. Model mixtures of these purees were prepared in our laboratory. DNA was isolated from fruit purees after and it’s amplifiability was comfirmed, it was successfully used in multiplex PCR to confirm the presence of raspberries, strawberries and blueberries in fruit purees. In the instrumental part, certain phenolic substences which are specific to red fruits were detected by HPLC in model and commercial mixtures.
Development and optimization of methods for detection of selected fruit species in foodstuffs
Šlosárová, Katarína ; Wikarská, Monika (referee) ; Fialová, Lenka (advisor)
Various types of adulteration of food products are becoming more frequent in the food industry than ever. That is no different for fruit products. This bachelor thesis deals with the detection of mango in fruit purées for infants through the use of qPCR and HPLC in three selected commercial products and their prepared replicas. Within the framework of molecular biology, different primers specific for mango were tested. Several primers, which were the most suitable for the demonstration of mango in fruit purées, were selected based on the course of the qPCR reaction, the size of the amplified product, specificity, and sensitivity. Using these primers, the presence of mango was proven in all six analysed samples. Regarding the instrumental part of the work, a rapid and simple method of extraction of phenolic compounds for their analysis by HPLC was tested, which has been previously successfully used on another plant matrix. This method was proved to be unsuitable for the extraction of phenolic compounds from fruit purées for the purpose of their authenticity verification using HPLC [1].
Detection of undeclared fruit species in foodstuffs using methods of molecular biology and instrumental methods
Svobodová, Petra ; Wikarská, Monika (referee) ; Fialová, Lenka (advisor)
This thesis is focused on the detection of apple component in fruit-based baby food. The theoretical part deals with the fruit itself – the apple; food adulteration as a reason for the control of food composition and methods, both instrumental and those of molecular biology, by which food adulteration can be detected. In the experimental part, commercial products containing apple puree were purchased and model mixtures were prepared as replicas of the purchased products. DNA was isolated from these samples, its amplifiability was verified, and the presence of the apple component was detected after the selection of suitable species-specific primers. Methanol extracts for HPLC were prepared from the above-mentioned samples using a procedure previously used for the extraction of phenolic substances from apple pulp [1]. Using this analysis, apple in fruit purees was to be identified using phloridzin as a marker for the presence of the apple component. The result was a successful detection of the apple component in both commercial products and model mixtures using qPCR. However, the tested method of phenolic substance extraction proved to be unsuitable for use in the analysis of fruit purees, as phloridzin was not detected either in the apple puree extract or in the model mixtures to which this puree was added.
Determination of hydroxymethylfurfural in honey
Dohnalová, Barbora ; Slavíková, Zuzana (referee) ; Diviš, Pavel (advisor)
Honey is a valuable food of a natural nature that can be subject to adulteration for higher profits. One method of detecting this adulteration may be to determine hydroxymethylfurfural, the formation of which is promoted by heating. The theoretical part of the thesis deals with the types of honey, their origin, and the possibilities of their falsification. HMF, its occurrence and use and methods for its determination are also described. The practical part is devoted to the description of the experiment such as sample preparation, measurement and evaluation. The HPLC (high performance liquid chromatography) method was used to determine HMF in honey, which can be used to determine even very low concentrations. There were five samples for the experiment, four of them directly from the beekeeper and one from the retail chain. All samples were compared for HMF content. The highest concentration of HMF was determined in a sample of commercially available honey. In domestic honeys, the HMF content increased with the age of the honey. The content of HMF in all honeys complied with Decree No. 76/2003 Coll.
Study of changes in the chemical composition of coffee during roasting
Kohoutová, Lenka ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with monitoring of changes in acrylamide and hydroxymethylfurfural levels in coffee during the process of roasting. Green coffee was roasted using two separate roasting modes (medium roast: temperature 210 °C for duration of 14 minutes, City roast: temperature 220 °C for 17 minutes). Concentration of acrylamide and hydroxymethylfurfural for various roasting durations was determined by high performance liquid chromatography. For the determination of acrylamide, linear growth of the concentration was observed. The final levels of acrylamide corresponded with levels given by the literature, although the characteristic trend of acrylamide formation was not observed. Typical trend of hydroxymethylfurfural formation was observed in samples roasted with City roast mode, while the first part of the trend was also apparent in samples roasted with medium roast mode. Final levels of hydroxymethylfurfural in roasted coffee were within the limits given by the literature.
Less common metabolites of steroid hormones in human physiology and pathophysiology.
Máčová, Ludmila
Less common metabolites of steroid hormones in human physiology and pathophysiology Not long ago, they have been less common steroid metabolites regarded as mere degradation products of steroid metabolism. Since the last decades, it has been discovered that these substances, which are occurring in the human organism at Nano molar concentrations, are involved in the regulation of physiological processes, such as the immune response, thermoregulation, development of cancer and activity against the major steroids. As the introduction, the presented thesis provides an overview of published data dealing with the less common metabolites of steroids. Experimental part is based on partial studies whose objectives were chosen in such a way to help reveal some of the missing intermediate steps in the mechanism of steroid hormones action. Because these steroids occur in only Nano molar concentrations, the highly sensitive and specific methods such as radio-immuno assay (RIA), gas chromatography combined with mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) had to be used. In the case of metabolites 16α-hydroxy-dehydroepiandrosterone and 7-oxo- dehydroepiandrosterone, we developed and statistically evaluated two novel RIA methods. These rapid and sensitive methods suitable for...
Study of the authenticity of spices and condiments
Štursa, Václav ; Golian, Jozef (referee) ; Urík, Martin (referee) ; Diviš, Pavel (advisor)
This disertation deals with geographical authentification of different types of spices and spice preparations. Investigated spice species were garlic (Allium sativum), ground pepper (Capsicum anuum), and dried carrot (Daucus carota). Theoretical part of the disertation describes main qualitative parameters of the examined species and production technology, means of food adulteration and statistic methods used in chemometrics. The aim of this dissertation was to verify the hypothesis whether it is possible to use targeted analytical techniques commonly used in quality control of spices and condiments, and statistical processing of measured data to distinguish samples of spices and condiments of different geographical origin. The use of non-targeted analysis was also investigated. Samples of garlic and ground pepper were used for targeted analysis. The examined parameters were dry matter and moisture of the sample, ash content, total phenolic content according to Folin-Ciocaulteu, carbohydrate content, alliin concentration, total nitrogen content, total color pigment (ASTA), pH of aqueous extract, total fat content, and concentration of selected elements (Ca, Cu, Fe, K, Mn, Mg, Na, P, Zn). The instrumental techniques used were molecular absorption spectrometry, inductively coupled plasma optical emission spectrometry and high performance liquid chromatography. The obtained data were statistically processed by analysis of variance (ANOVA) and principal component analysis (PCA). Using statistical analysis significant differences between samples that came from more distant areas were found. However, samples from closer areas could not be distinguished. The researched hypothesis could not be unequivocally confirmed or refuted. Metabolic fingerprint of carrot samples was determined using non-targeted analysis. Metabolic analysis was performed using the tandem LC-TOF-MS technique. The data were processed by recursive peak extraction (BRE) and subsequently uvaluated with PCA. The samples were divided into clusters according to their origin. Targeted and non-targeted techniques have great potential in verifying the geographical authenticity of different types of spices. However, the main condition is consistent and sufficient sampling, guaranteed information on the origin of the sample and obtaining a sufficient amount of input data for statistical analysis.
Biochemistry and pathobiochemistry of phylloquinone and menaquinones
Dunovská, Kateřina ; Klapková, Eva (advisor) ; Uřinovská, Romana (referee) ; Skoumalová, Alice (referee)
Vitamin K belongs to the family of fat-soluble vitamins, which is not determinated in clinical laboratories. It is a cofactor necessary for posttranslational γ-carboxylation of glutamyl residues in selected proteins such as the osteocalcin, and procoagulation factors II, VII, IX, X. Vitamin K deficient individuals appear to have more undercarboxylated proteins, which are functionally defective. Lack of this vitamin has been associated with risk of developing osteoporosis and cardiovascular diseases. The aim of this work was to develop and validate the HPLC method and the LC-MS/MS method for determination of three vitamin K's forms - vitamin K1, MK-4 and MK-7 in serum. After successful validation of both methods, patient samples and healthy population samples were measured. There were measured 350 patient samples by HPLC method. These samples were divided into two groups - patients with diagnostic of osteoporosis and patients without osteoporosis. We measured 946 samples by LC-MS/MS method. Samples were divided into groups: patients with osteoporosis, patients without osteoporosis, healthy population, patients with osteopenia and patients with cystic fibrosis. The reference range of vitamin K in healthy population was obtained by LC-MS/MS method. The next aim was to compare the effectiveness of...

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