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Influence of some microbiogenic elements on carotenogenic yeasts
Pulkrábek, Josef ; Holub, Jiří (referee) ; Obračaj, Jan (advisor)
Carotenogenic yeasts of the genus Rhodotorula are well known for their production of a variety of economically valuable and otherwise difficult to produce compounds such as fatty acids, carotenoids, ergosterol, and ubiquinone. This study investigates the effect of the addition of select microbiogenic elements (Fe, Se, I) and their combinations into mineral cultivation media on the production of the mentioned valuable metabolic products and the rate of element sorption into the biomass of the strains of Rhodotorula mucilaginosa, Rhodotorula kratochvilovae, and Rhodotorula toruloides. Additionally, the sorption of zinc oxide, ferrous fumarate, and selenomethionine into previously cultivated biomass was measured with sorption times of 2 and 24 hours. Fatty acid content was determined using GC-FID, while carotenoids, ergosterol, and ubiquinone were analyzed using HPLC-DAD, with element content being quantified using ICP-OES and IC. With a few exceptions, the production of metabolic products was decreased with the addition of elements into the media and inversely correlated with their concentration. Higher concentrations generally showed greater absolute amounts of sorbed elements but lower relative amounts, which, combined with reduced production of metabolic products shows that the media are not ideal for the cultivation of the given species. The elemental contents were such that biomass supplemented with individually sorbed elements would vaguely align with ESFA dietary reference values, but cultivation in media with a mixture of added elements could result in the biomass containing either insufficient iron or excessively high levels of selenium. Sorption levels were relatively low (5 to 22 % for iron and 0.5 to 2.5 % for selenium). Indicating that cultivation in media with lower concentrations of elemental additives is a promising area for future research.
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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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The use of near-infrared spectroscopy for characterisation of raw material for sunflower oil production
Vystavělová, Petra ; Vránová, Dana (referee) ; Pudilová, Ludmila (advisor)
This diploma thesis provides summary information about using of near infrared spectroscopy for monitoring of high oleic acid content in sunflower seed. The calibration for high oleic sunflower seed was performed by using calibration model PLS - „Partial least squares. Gas chromatography was used as a reference method. Based on this knowledge thirty samples of high oleic sunflower seeds were measured and evaluated on this calibration. The last part of diploma thesis consist of comparison of oleic acid results measured by near infrared spectroscopy and gas chromatography used as reference method, and discussion about the measurement accuracy and evaluation of suitability of using these methods.
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The assessment of fatty acids in cheeses
Rajnochová, Veronika ; Omelková, Jiřina (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the determination of fatty acids in natural Edam cheese. The theoretical part briefly characterize the natural Edam cheese, main attention is paid to lipids, fatty acids and the possibility of their determination by gas chromatography. In the experimental part the content of fatty acids in the model samples of natural Edam cheese produced at Tomas Bata University in Zlín was determined. The method according to ISO 1735 was chosen for extraction of lipids from the samples , the method according to ISO 5509 using methanol solution of potassium hydroxide was chosen for the esterification of fatty acids ,. The resulting methyl esters were determined by gas chromatography with FID detection.
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The assessment of aroma active compounds in cheeses
Ryglová, Hana ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
This work deals with aroma active compounds of Edam cheese, i.e. natural hard cheese with low heat curd. Aroma active compounds contribute to overal aroma of cheese. They are volatile compounds, which include alcohols, aldehydes, ketones, fatty acids, esters, lactones, terpenes etc. These compounds were identified and quantified using SPME/GC/FID method in the model samples of Edam cheese, produced at Tomas Bata University in Zlin. In total 18 volatile compounds were identified, 3 aldehydes, 4 ketones, 7 alcohols, 1 ester and 3 acids. Differences in number of compounds identified, as well as in the contents of them, were found between samples. Low number of compounds and also their low total content correspond to the initial phase of cheese ripening.
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Sensorial and analytical evaluation of cheese analoques flavour
Brabcová, Lenka ; Horváthová,, Viera (referee) ; Vítová, Eva (advisor)
The aim of the diploma thesis was to determine the influence of different kinds of fats on the content of aromatic active compounds and total flavour of processed cheese analogues. Samples of the cheese were produced by Tomas Bata University in Zlín from concentrated milk fat, butter, palm fat, coconut fat and sunflower oil. The aromatic compounds were isolated from samples of fats and processed cheese analogues via HS-SPME-GC method. A fibre with polar stationary phase CAR/PDMS was used for capturing of aromatic active compounds. In different contents, total of 32 aromatic compounds were determined. The cheese from concentrated milk fat and butter had the highest content and cheese from sunflower oil had the lowest. For determination of acceptability and flavour, the cheese analogues were sensory evaluated at the same time. Ordinal test, evaluation via scale and profile test were used. Cheese made from concentrated milk fat and coconut fat were always evaluated as the best, cheese made from sunflower oil were evaluated as the worst. Finally results between SPME-GC and sensory analysis were compared. It was stated that the kind of fat used for production of processed cheese analogues significantly influences the content of aromatic compounds and thus influences flavour of the cheese analogues.
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Assessment of chosen aroma compounds in foods
Greifenthalová, Ivana ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis is focused on the problematic of assessment of 26 most important allergenic aroma compounds in foods, flavoured herbal teas were chosen as the model samples. Aroma is the one of the main characteristics of tea, which is closely linked to taste and odour. The theoretical part of this work is focused on the characteristics of tea, tea types, producing technology, classification according to the fermentation and also their undeniable impact on the human organism. In the experimental part, the allergenic aroma compounds in 10 chosen samples of flavoured tea were identified and quantified using the solid phase microextraction (SPME-GC-FID) in conjunction with gas chromatography. The work also includes sensory evaluation of taste and smell of tea samples by qualified assessors.
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Determination of residues of the selected pesticide effective substances in wine using the GC/MS method
Ehrenbergerová, Martina ; Benešová, Karolína (referee) ; Mikulíková, Renata (advisor)
The grape is one of the oldest cultivated plants. It can be consumed as a fruit or it can be used as a raw material for making stews, juices or the cultivated drink – wine. Generations of wine-makers have been striving to improve both the cultivating conditions of vineyards and the quality of wine. Many harmful elements, such as herbivorous pests, diseases and storms are important factors that can have a negative impact on crop quality. To regulate the effects of these factors, an integrated protection system is used, incorporating agronomical measures, resistant varieties and a wide spectrum of pesticides. However, increasing the usage of pesticides brings certain dangers to both the production quality and the environment. This necessitates the monitoring of the negative effects, including the content of pesticide residues in the grapes. My thesis studies and experimentally assesses selected pesticide residues in certain wine samples.
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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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Characterization of yeast and algae metabolites by instrumental techniques
Kurowska, Klára ; Márová, Ivana (referee) ; Němcová, Andrea (advisor)
The presented diploma thesis deals with the analysis and production of selected microbial metabolites of the yeast Rhodotorula kratochvilovae in comparison to various species of microalgae. The theoretical part summarizes the knowledge about the conditions for optimal growth and production of secondary metabolites. Analytical methods, by which metabolites were quantified and evaluated, were also described. In the experimental part of this thesis, the amount of accumulated biomass, exoglycolipids, intracellular lipids, phycobiliproteins and carotenoids according to various nutrient sources in the culture medium was studied. Specifically, the yields of these metabolites were investigated in the utilization of various sources of nitrogen (yeast extract, urea, ammonium sulfate, ammonium chloride and potassium nitrate), carbon (glucose, mannose, xylose, glycerol and lactose) and at variable C / N ratios (20; 40; 70; 100 and 120: 1) ideally selected sources of observed nutrients in partial experiments. The last part of the experiment was focused on comparison of the analysis of metabolites of autotrophic algae (chlorophylls, phycobiliproteins and lipids).
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