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Determination of honey authenticity and adulteration by anion exchange chromatography
Ždiniaková, Tereza ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
Cieľom tejto diplomovej práce je stanoviť kvalitu a zloženie medu, taktiež stanoviť jeho botanický pôvod na základe profilu sacharidov v mede. Med je prírodný produkt vysokej kvality a vďaka značnej spotrebe a nemalej trhovej hodnote je tiež terčom na falšovanie. S cieľom identifikovať podvody a cudzorodé látky, pochádzajúce z cukrových sirupov, boli analyzované oligosacharidy a polysacharidy na báze maltodextrínov. Teoretická časť popisuje chemické zloženie medu a hlavné princípy aplikovanej inštrumentálnej techniky. Poskytuje literárny prehľad existujúcich analytických metód na stanovenie sacharidov prítomných v mede a na odhalenie jeho falšovania. Boli definované hlavné body falšovania a autenticity, vrátane legislatívnych aspektov a opisu bežných druhov falšovania. Experimentálna časť obsahuje postupy, ktoré vedú k vývoju a optimalizácii chromatografických podmienok a parametrov elektrochemického detektora na stanovenie sacharidov a maltodextrínov (oligosacharidov a polysacharidov) vo vzorkách medu. Použitá analytická technika bola vysoko účinná aniónovo-výmenná chromatografia (HPAEC) spojená s pulzným amperometrickým detektorom (PAD). Vyvinutá a optimalizovaná chromatografická metóda bola taktiež validovaná z hľadiska linearity, dynamického rozsahu, analytických limitov, presnosti a správnosti. Na záver bola táto vypracovaná metóda úspešne zhodnotená analýzou autentických a falšovaných vzoriek medu rôzneho botanického pôvodu pochádzajúcich z členských štátov EÚ.
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Characterisation and maturation process of Edam type cheese
Dostálková, Andrea ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the assessment of aroma compounds and free/bound fatty acids in model samples of Edam type cheeses. Various combinations of microbial cultures, basic mesophilic and four selected strains of thermophilic Lactobacillus casei and Lactobacillus plantarum, were used for cheese production. The main aim was to judge the influence of microbial cultures on content of measured parameters, the changes during ripening were also followed. The HS-SPME-GC-MS method was used for identification and semiquantification of aroma compounds. The lipids from cheese were extracted based on ISO 1735:2004, fatty acids were identified and quantified using GC-FID method after conversion to methyl esters by acid esterification with boron trifluoride in methanol. In total 50 volatile compounds were identified in samples, 11 alcohols, 5 aldehydes, 7 ketones, 6 acids, 10 esters, 3 lactones, 2 sulphur compounds and 6 „others“; all of them are considered as aroma active. About 30–40 compounds were identified in single samples, alcohols, acids and ketones were the predominant. The number as well as the content of compounds identified decreased slightly during ripening. In total 17 free/bound fatty acids were identified in samples, their content also decreased during ripening. Myristic, palmitic, stearic and oleic acids were the predominant. The significant differences (p
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Development of method for determination of qualitative parameters of cocoa powder
Vránová, Petra ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
The theoretical part of the master’s thesis is focused on a brief botanical characterization of the cacao tree and its most famous varieties discussed. Furthermore, the chemical composition of cocoa beans is described with an emphasis on theobromine and caffeine. There is also mention of the cocoa beans the cocoa bean processing technology for cocoa liquor and cocoa powder, which are then used in food industry. Additionally there is a shorta short description of the legal requirements relating to cocoa. In this part are also two chapters are devoted to the description of instrumentation of high performance liquid chromatography (HPLC) and inductively coupled plasma optical emission spectrometry (ICP-OES). The experimental part deals with analyzes of cocoa powder, cocoa beans, cocoa liquor and waste cocoa beans sold as a "tea mixture". A total of 10 legislation-recommended parameters have been identified in the listed raw materials, such as caffeine, theobromine and sucrose, heavy metal and potassium, fat content etc. The highest content of theobromine was determined in cocoa powder 178.363 mgl-1, caffeine in cocoa beans 16.096 mgl-1. All samples analyzed contained a little amount of sucrose as expected, the highest concentration was found in the tea mixture samples in both the water: ethanol sample of 84.069 mgl-1, and the sample solution in water of 65.897 mgl-1.
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Possibility of further use of elderberry marc
Sedláčková, Lucie ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This Diploma thesis talks about the production of concentrates and lyophilisate from the extract of elderberry moldlings (elderberry, Sambuvus nigra L.) and by determination by chosen chemical characteristics of these products. The theoretical part includes the botanical characteristics of the plant species Sambucus nigra L. Next is the part that is dedicated to biologicaly active substances found in elderberry and it‘s possible usage in the food industry. Next is the part where the extraction, purification and indentification of anthocyanic dyes are described. In the next part is the analyrical method HPLC described, including the description of instrumentation. The last part talks about the description of the used methods: methods for the concentration of the extract, UV-VIS spectrophotometry, determination of phenolic compounds, determination of dry matter, determination of active acidity and the overall titrating acidity. The experimental part contained the optimalization of the process of producing the extract from elderberry moldings. The extract obtained was then concentrated for preservation and characterization purposes based on selected chemical properties. The total content of anthocyanin dyes was chosen as a quality parameter. The most suitable process for the preparation of the extract was chosen to be the ratio of moldings and solvent 1:2, 4 (m/V). The most suitable solvent was chosen to be a mixture of water and ethanol in a ratio of 1:1 (V/V). According to the needs of the submitter, an extract with the use of water as the extraction agent is also provided. The prepared extract was then concentrated on a vacuum evaporator or lyophilized for storage purposes. The dye degradation while using the evaporator was the lowest in a 40 ° C water bath. The final products were characterized by the determination of soluble solids, pH, titration acidity, total phenolic compounds and total anthocyanin dyes. The anthocyanin pigments contained identified by liquid chromatography are: cyanidine-3-sambubioside, cyanidine-3-glucoside, cyanidine-3-sambubioside-5-glucoside, and cyanidine-3,5-diglucoside The total content of anthocyanins in the concentrate was determined to be equivalent to cyanidine-3-glucoside at 2.8 gl-1 and in the lyophilisate 2.5 gl-1.
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Preparation and characterization of extract from elderberry flowers
Lukšová, Leona ; Zemanová, Jana (referee) ; Vespalcová, Milena (advisor)
This diploma thesis deals with the determination of conditions for the preparation of elderberry extract so that the prepared extract retains as many biologically active substances as possible and the way of preserving this extract. Furthermore, the work deals with the transmittance of already specific phenolic acids, namely chlorogenic acid, coffee and ferulic skin, through the Franc diffusion cells. In the theoretical part of the thesis there is a taxonomic classification, description and use of elderberry. Furthermore, significant active substances, in particular phenolic acids, are mentioned. beneficial effects on the skin. The anatomy of the skin and the problem of the penetration of phenolic acids through the skin are described in detail. Finally, a description of high performance liquid chromatography is provided. The experimental part is devoted to verification of optimal conditions for preparation of extract. The best option is to extract the flowers with water at 100 ° C for 10 minutes in a ratio of 1 part by weight of dry flowers and 10 parts by volume boiling water. The ratio of flowers and stems to the phenolic acid content of the extract was also investigated. In the flower extract and its thickened version, the skin permeability was examined by transdermal absorption. The aim of this experiment was to find out if and how much the above mentioned phenolic acids go through the skin. As skin membrane, pork skin from the auricle was used. All determinations of the above phenolic acids in all samples were carried out by liquid chromatography.
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Comparison of the properties of chokeberry spreads of different origins, comparison and different production technologies
Kapiton, Ulyana ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This diploma thesis deals with comparison of the properties of chokeberry spreads of different origins, composition and different production technologies. The theoretical part contains a brief description of the chokeberry – Aronia melanocarpa, an overview of the most important substances contained in the chokeberry and examples of the use of aronia, not only in the food industry. Furthermore, the legislative requirements for the production of spreads and the production technology itself are described. In this thesis is also described a new patented technology of spread production using HTD technology. Another part of the theoretical part is a literature review of the determination of anthocyanins in chokeberry by HPLC method. The experimental part describes the laboratory procedures used for determination of dry matter, carbohydrates by HPLC with ELSD detector, anthocyanin dyes, total phenolic compounds and antioxidant activity. Another part of the work was a questionnaire survey and sensory analysis of selected chokeberry spreads. The panel members prefered the Lowicz chokeberry spread, for which was determined 29,39% dry matter, 15,15 mg.g-1 anthocyanins, 9,20 mg.g-1 total phenolic compounds, 158,42 mg.g-1 fructose and 151,26 mg.g-1 glucose and the antioxidant activity was determined to be 5,94 mg.g-1.
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Application of microextraction techniques for analysis of biological samples
Lučaj, Martin ; Vespalcová, Milena (referee) ; Dvořák, Miloš (advisor)
This bachelor thesis deals with the analysis of basic drugs in biological samples by in line coupling of supported liquid membrane (SLM) to capillary electrophoresis (CE). The tITP method was included as an on-line preconcentration step to achieve better detection limits with ammonium acetate as the tITP stacker and acetic acid as the CE background electrolyte. The practical part of the thesis focuses on the optimization of the tITP and the SLM extraction conditions in the analysis of basic drugs in complex biological samples (human urine). The best analytical results were achieved with hydrodynamic injection of ammonium acetate for 15 s and basic drugs for 15 s. The donor was alkalised with 10 mM sodium hydroxide and acceptor was acidified with 10 mM hydrochloric acid. From the results, the in-line coupling of SLM extraction to CE and stacking by tITP is an efficient method allowing direct analysis of complex samples with improved sensitivity of the analytical method.
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The basic chemical parameters of several varieties of cherries
Boberová, Jana ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
This bachelor thesis deals with determination of basic chemical parameters in sweet cherry (Prunus avium). In the theoretical part, the taxonomic classification of the cherry, its botanical characteristics and the pomology of several cultivars are mentioned. Also, the history of cultivation, appropriate conditions and most common diseases are listed. The last chapter deals with the chemical composition of the fruits. In the experimental part, the determination of selected chemical parameters of various cultivars (Karešova, Napoleonova and Stark Gold) were determined. The content of total solids was determined in the range of 14.53–18.15 %, soluble solids 13.96–16.44 %, ash 0.34–0.44 %, reducing sugars 6.89–10.18 % and nitrogenous substances 0.056–0.116 %. Ascorbic acid content was set at 26.1–44.1 mg/kg. The titratable acidity was determined in the range of 6.15–8.86 g of predominant malic acid in 1 kg of cherry and a formol number was determined from 194 to 297 ml of 0.1 M NaOH per 1 kg of edible fraction. The amount of anthocyanins was determined at 4–686 mg cyanidin-3-rutinoside/kg and total phenolic compounds at 0.91–1.47 g gallic acid/kg. All data are based on fresh fruit weight.
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The repeatability of the method for assessment of free fatty acids
Buldra, Martin ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the assessment of free fatty acids in sunflower oil. Theoretical part focuses on the general characteristics of fatty acids and lipids. The experimental methods suitable for assessment of fatty acids are described, with the emphasis on gas chromatography, the basic method of their assessment. In experimental part two methods for free fatty acids assessment: with/without previous fractionation, were compared and then the repeatability and reproducibility of selected method – the direct esterification of free fatty acids using BF3 as a catalyst, were verified. The assessment of fatty acids methyl esters was done using gas chromatograph with flame-ionization detector.
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Use of secondary raw materials from wine production
Lajtman, Roman ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with using of grape pomace, waste from wine industry. It also deals with the determining of total phenolic substances in a grape pomace. The theoretical part focuses on the characteristic of grape, the chemical composition of wine, making of wine and mainly on use of secondary raw materials. It also describes phenolic substances, their division and finally something general about using experimental methods. In the experimental part a red grape pomace´s extraction was made. The extractions were made in different solvents, in a mixture ethanol-water (ratio 20:80; 40:60 and 60:40), also in a mixture glycerol-water (ratio 10:90; 20:80 and 40:60) and at the end in water. The extractions were made in a different time and the purpose was to optimize the extractions and to get the highest yield of phenolic substances, antioxidants. Time and economically side played an important role to find out and to choose the best solvent. In the results, as the best and the optimal extraction´s solvent on extraction of red grape pomace was chosen the mixture ethanol-water and ratio was 60:40. That mixture extracted the most phenolic substances and relatively in the shortest time. During the optimization of sample weight was found out that optimal sample weight is 4 g of grape pomace. At the end repeated extraction was made. It is obviously practically worthless. After second step of extraction, the concentration of phenolic substances is more than a half lower than at the first step.
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