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The effect of a storage conditions on fatty acids in processed cheese
Němcová, Tereza ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with the changes in content of fatty acids in long-lasting stored sterilized processed cheeses. Cheeses were stored under different temperatures 6 ± 2 °C, 23 ± 2 °C and 40 ± 2 °C during 23 months. Measurements was made in 16th and 23rd month of storage. The samples of sterilized processed cheeses were extracted by using mixture of solvents (ethanol, diethylether and petrolether). The obtained fat was then saponified by methanolic solution of potassium hydroxide. The methylesthers were analyzed by gas chromatography with flame ionization detection. Lauric, myristic, palmitic, oleic and stearic acids were the most abundant in cheeses. The yield was measured in these main acids. To summarize the content of fatty acids decreased during time of storage and also by influence of storage temperature higher than in refrigerator.
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Determination of caseins in cow milk
Gejdošová, Lucie ; Zemanová, Jana (referee) ; Vespalcová, Milena (advisor)
The diploma thesis is dealing with design of analytical method for determination of caseins in cow‘s milk. Capillary electrophoresis was used as separative method. The developed procedure was verified on real samples. Theoretical part gives basic information about caseins. Their chemical and physical properties, structure, way of manufacturing, usage in food industry and non-food applications are described. There are further some nutritional factors mentioned, whose application in cattle nutrition can affect milk composition, especially milk protein concentration. Literary part contains summary of capillary electrophoresis methods used for casein determination. Experimental part describes used separative system, procedure of casein isolation from milk and casein content in individual milk samples. Separation of milk caseins was performed in an untreated fused-silica capillary with dimensions of 50 um i.d. x 96 cm total length (71 cm effective length). Phosphate buffer (10 mM, pH 2,5) served as the background electrolyte. Casein from milk was obtained by isoelectric precipitation at pH 4,6 after adding 10% acetic acid. Product was washed with acetone to remove fat and dried. Total casein yield was the highest in bio-milk (27,04 g/l), the lowest in skim long-life milk (22,04 g/l). The diploma thesis has arisen on the basis of cooperation of Institute of Food Science and Biotechnology, Faculty of Chemistry, Brno University of Technology and Research Institute for Cattle Breeding, Ltd., Department of Animal Nutrition Physiology in Pohořelice.
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An antimicrobial activity of Stevia rebaudiana extracts
Mlatečková, Tereza ; Zemanová, Jana (referee) ; Vespalcová, Milena (advisor)
This master thesis is oriented on study antimicrobial effects extracts and macerates from cure Stevia rebaudiana Bertoni. Teoretical part describes basic information about plant Stevia, summary of health significant matters contained in Stevia and posobilities preparing extracts from Stevia. Antimicrobial effects extracts and macerates from cure Stevia were testing on food-borne bacteria (Bacillus cereus and Micrococcus luteus) and yeasts (Geotrichum candidum and Hansenula anomala). Microorganism, extracts and macerates were chosen on basis previous study (Study of antimicrobial effects Stevia Rebaudiana extracts, Eva Rakovská). For screening antimicrobial activity were determined the growth curves by using turbidimetrie for bacteria and direct treetment metod of cells number for yeasts. Antimicrobial effects were confirmed aplication with diffusion pit method on the agar ranges. From the results flow the testing extracts and macerates from stevia analysed antimicrobial effects. The best effect was demostrated on macerates and the most sensitive was bacteria Micrococcus luteus with the best inhibitoring effects.
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Thermophilic Microorganisms Application for Lignocellulose Materials Biodegradation
Klašková, Lenka ; Zemanová, Jana (referee) ; Babák, Libor (advisor)
The plant cell wall consists of several layers: cellulose, hemicellulose, lignin and pectin. These biopolymers are degraded by many microorganisms. Extracellular enzymes are used for biodegradation by microorganisms. This thesis was focused on studying the impact of cultivation conditions on the production of extracellular enzymes at carboxymethyl cellulase and pectin when a mixed thermophilic culture containing Bacillus and Thermus microorganisms is used. The cultivation was carried out in flasks on a shaking machine with a shaking speed of 99 min-1 at a temperature of 60°C. The monitoring covered cellulolytic and polygalacturonase activities, protein concentration by the Biuret method, concentration of reducing substances by the Somogyi and Nelson methods, and the temperature optimum.
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View of existing supplements for tissue of brain nutrition.
Fojtíková, Veronika ; Zemanová, Jana (referee) ; Vránová, Dana (advisor)
This diploma thesis is related to usage of food supplements in general. It observes which food supplements are mostly used, how often and in which period they are used and also which supplements forms population prefer. Next is this diploma paper focused on supplements for the support of cerebration, concretely up to supplements containing Ginkgo biloba. It studies their vascular activity, effect on memory and concentricity in various age groups. Also HPLC method for quick analysis of selected food supplements containing Ginkgo biloba was tested.
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Study of quality of different vegetable oils
Martinů, Michaela ; Janoušková, Eva (referee) ; Zemanová, Jana (advisor)
The aim of the diploma thesis was determined the particular fatty characteristics of various vegetable oils in dependence on their storage life and storage conditions. Storage conditions were defined by room temperature and coolroom temperature. The fourteen oils were used for analyses, namely linseed oils, castor oil, grape seed oil, almond oil, olive oil, jojoba oil, avocado oil, apricot kernel oil, corn oil, rice bran oil, macadamia nut oil, soya bean oil, pumpkin seed oil and sunflower oil. All tested oils were supplied by firm M+H, Míča a Harašta s.r.o. The fatty characteristics included the saponification value, the acid value, the iodine value and the thiobarbituric value. The ester values and the percentage glycerol content were counted on the basis of the saponification value and the acid value. Time dependences of all fatty characteristics were figured to graphs and they were compared on various storage conditions. The fatty characteristics indicated lower values in storage of oil samples in coolroom than at laboratory temperature.
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Analysis of Echinacea content compounds
Michalíček, Jan ; Vespalcová, Milena (referee) ; Zemanová, Jana (advisor)
Rostliny rodu Echinacea jsou léčivé byliny stimulující imunitní systém. Používají se zvláště v boji proti chřipce a infekcím horních cest dýchacích. V této práci bylo analyzováno 7 komerčních výrobků obsahujících výtažky z rostliny Echinacea vysokoúčinnou kapalinovou chromatografií. Bylo provedeno kvantitativní stanovení derivátů kyseliny kávové, jež jsou látky zodpovědné za léčivé účinky rostliny. Zjištěné obsahy kyseliny chlorogenové, kávové, cichorové a echinakosidu byly porovnány v jednotlivých výrobcích. Dále byly připraveny extrakty z kořene, listů a květů třapatky nachové pomocí extrakce za zvýšeného tlaku extrakčního rozpouštědla při různých podmínkách, aby se z obsahu účinných látek v nich přítomných zjistilo, které extrakční podmínky jsou nejlepší. Z naměřených dat bylo zjištěno, že největší celková koncentrace obsahových látek je přítomna ve výrobku Imunit Echinaceové kapky firmy Simply You. Jako nejlepší extrakční podmínky se ukázaly teplota 80 °C v kombinaci s rozpouštědlem ve složení EtOH/voda = 40/60, a to jak při extrakci kořene, tak i listů a květů.
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Monitoring of the influence of selected synthetic preservatives on the stability of cosmetic emulsions O/W
Holubová, Anna ; Vítová, Eva (referee) ; Zemanová, Jana (advisor)
This bachelor’s thesis collects available information on commercially supplied cosmetic preservatives Sensiva PA 20 (ingredients by INCI: phenethyl alcohol, ethylhexylglycerin), Euxyl K 900 (ingredients by INCI: benzyl alcohol, ethylhexylglycerin, tocopherol) and Euxyl PE 9010 (ingredients by INCI: phenoxyethanol, ethylhexylglycerin) from German company Schülke & Mayr, especially with regard to the assessment of their potential influence on the stability of cosmetic emulsion O/W. Subsequently, based on the literature review, selected methods were applied, their combination may prospectively serves to required evaluation of the influence on the stability of studied preservation systems.
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Cheese curd parameters influence to selected economic factors of production of cheese with white fungus
Pavlíčková, Žaneta ; Zemanová, Jana (referee) ; Babák, Libor (advisor)
The theme of this diploma thesis is the monitoring of influences on economic aspect of the production of the blue cheese "Hermelín" in the company Pribina. The objective was to specify the dependencies of the deviations of the features of productive cow's milk and of cheese curd made from it and their economics impacts. For this purpose, the analyses of curd grain, whey and cheeses just formed were executed. The samples were taken and analyzed during the manufacturing of cheeses in the factory. Another goal was to try to design a quick operational method for measuring the firmness of curd grain, which is a factor theoretically dependent on renneting qualities of milk and indicating losses of valuable components from cheese curd to whey. The firmness of grain along with these losses may cause negative deviations from required standard of final products, especially at parametres needed for entry of cheeses on sale, such as total solids, weight or content of fat. Concerning productive pasteurize milk, the most attention was focused on the milk coagulation time and its influence on successive phases of manufacturing and on final product. Milk coagulation time is an essential technological quality of milk and it is participant on quantitative and qualitative production of cheese factory. It has been proved that milk coagulation time is notably affected by its titrating acidity, statistic analyse found this influence as very statistically significant (P
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Possibilities of determination of metalocompounds present in living systems
Hauerlandová, Petra ; Zemanová, Jana (referee) ; Vitoulová, Eva (advisor)
This bachelor thesis deals with the topic of metallomics. There are explained basic concepts and definitions, differences between the metal-binding proteins and metalloproteins. This thesis also deals with metallothioneins and theirs basic types. The study describes possible interactions of metals and organic compounds. Attention is paid to interactions between metals and peptides or proteins. There are given examples of some essential metals, which are linked to important organic compounds, which are necessary for the proper function of the organism. Mainly there are described enzymes necessary for the human body. There are also referred organic compounds of toxic metals. Another part of the thesis is devoted to analytical methods used for determination of metallocompounds. There are described methods for separation and detection, which are combined for qualification and quantification of metallocompounds. There are referred examples of the determination of some metallocompounds.
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