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Assessment of fatty acids in selected type of cheese
Chmelařová, Adéla ; Sůkalová, Kateřina (referee) ; Vítová, Eva (advisor)
This bachelor thesis is focused on identification and quantification of free and bound fatty acids in commercially available white mold cheeses: Hermelín, Kamadet and Olmín, using gass chromatography withflame ionization detection. Theoretical part of the thesis is dealing with the classification of cheeses with the main attention to white mold cheeses. In a following part cheese production technology is described, lipids and fatty acids are characterised including the possible methods for their assessment, mainly gass chromatography. Experimental part the contents of free and bound fatty acids in selected samples of white mould cheeses were compared. The method in accordance with ČSN EN ISO 1735:2005 was selected for lipid extraction. Fatty acids were identified as methylesters using acid esterification with methanolic solution of bortrifluorid as a catalyst. In total 21 free and bound fatty acids were detected in samples.
Assessment of aroma active compounds in selected type of cheese
Páral, Marek ; Mahdalová, Martina (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the determination of aroma active compounds in white mold cheeses, i.e. soft, mold cheeses maturing from the surface. In the theoretical part, cheeses are generally characterized, their chemical composition, properties and process of production are described. After that It´s focused on aroma active compounds. The metabolism of their formation in cheese and their determination by means of solid phase microextraction and gas chromatography with mass detection are described. In the experimental part of the bachelor thesis, the SPME-GC-MS method was used for identification and semiquantitative determination of aroma active compounds in three samples of white mold cheeses made in the Czech Republic purchased in a market. Comparison of cheeses showed differences in the number and types of determined compounds as well as in total contents. A total of 66 volatile compounds were identified in samples; of those 1 aldehyde, 17 alcohols, 19 esters, 9 carboxylic acids, 15 ketones, 1 sulphur compound ¨ and 3 hydrocarbons.
The basic chemical parameters of several varieties of sour cherries
Komárek, Šimon ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
This bachelor thesis deals with determination of basic chemical parameters in sour cherry (Prunus cerasus). Three different cultivars Köröšská, Pandy 6039 and Šumadinka were examined. The content of total solids varied from 13,32 to 15,22 %, soluble solid content amounted for 12,04–14,60 %, ash 0,4 %, reducing sugars 4,9–6,9 %, nitrogenous substances 0,11–0,12 %, L-ascorbic acid 343–456 mg/kg. Titratable acidity ranged from 15,1 to 21,8 g malic acid equivalent/kg, formol number 268–373 ml of 0,1 NaOH/kg. Total anthocyanins varied from 308 to 1104 mg cyanidin 3-glucoside equivalent/kg and total phenolics ranged from 1,05 to 3,99 g gallic acid equivalent/kg. All data are applied to fresh fruit weight.
Assessment of fatty acids in processed cheese
Mitra, Michal ; Sýkora, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with determination of fatty acids in samples of processed cheeses made at Tomas Bata University in Zlín. In the theoretical part, lipids and fatty acids are characterized. Subsequently, the issue of production, distribution and composition of natural and processed cheeses is discussed. The conclusion of the theoretical part is focused on the assessment of fatty acids, i.e. their extraction and the determination by gas chromatography. In the experimental part, the fatty acid content of the seven samples of processed cheese was compared on the basis of different temperatures and the time of their production. The ČSN EN ISO 1735 method was used for extraction of fat. The method with methanolic potassium hydroxide solution was used for esterification. The determination of fatty acid methyl esters alone was accomplished by gas chromatography with a flame ionization detector. Based on the comparison with the standards, 17 fatty acids were identified in the samples.
Impact of nitrogen fertilization and drought on glutenins content in winter wheat
Vostrejš, Pavel ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
In this bachelor thesis the effects of nitrogen fertilization and drought stress on glutenin fraction of winter wheat (Triticum aestitivum L.) were studied. Winter wheat cultivar Tiguan was grown under different rainfall mode, on the one hand in drought (DRY), on the other hand in normal downfall (WET). Part of the samples was treated with nitrogen fertilization at a dose of 140 kg / ha (N140), the other part remained without fertilization (N0). After the gliadins were separated, the glutenins from the samples were extracted with 50% isopropanol with 1% DTT. Individual glutenin fractions were separated by SDS-PAGE and quantified by computer densitometry. The drought did not have a statistically significant effect on any of the glutenin subunits. Nitrogen fertilization caused an increase in the total amount of glutenin as well as the amount of individual subunits. Interaction of water regime treatment and fertilization has not led to an increase in glutenin levels in HMW 3 GS and LMW 5 GS in DRY conditions.
The content of aroma active compounds in sweets
Paulišová, Sabina ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
This bachelor thesis focuses on identification of aroma active compounds in selected samples of non-chocolate sweets. Based on the results obtained, the aromatic profile of the individual samples is compared. The theoretical part deals with aroma active compounds, legislation and technology of manufacturing non-chocolate sweets. Further experimental technique and the methods used in practical part, namely solid phase microextraction and gas chromatography with mass spectrometry detection are presented. In the experimental part volatile aroma active substances were identified in green colored jelly candy samples available in the common market. For this purpose, the HS-SPME-GC-MS method was used. The individual samples differed in type and number of volatile compounds, depending on the manufacturer. In total 72 different compounds, including 11 aldehydes, 14 alcohols, 27 esters, 1 heterocycle, 8 carboxylic acids, 6 ketones, 4 hydrocarbons and 1 sulfur compound were found.
Sensory evaluation of sweets
Boboková, Alexandra ; Burdějová, Lenka (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with a sensory analysis of a selected type of non-chocolate sweets – gummy jellies with sour coating. The theoretical part describes raw materials needed for the production of non-chocolate sweets, a list of non-chocolate sweets and their technological production are also mentioned. Sensory analysis and sensory evaluation methods are briefly described. The experimental part is focused on sensory analysis of selected yellow-coloured/lemon flavoured samples from five different producers. The samples were evaluated using a scale based on their appearance, colour, flavour, aroma and texture. Furthermore, the sensory profile and evaluation of aftertaste using time intensity methods were applied. Common consumers were represented by 20 untrained assessors from the Faculty of Chemistry of BUT. Bright colour contributed positively, while hard texture negatively to the overall evaluation of samples.
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.
Antioxidant activity of green tea extracts
Šedý, Michal ; Vítová, Eva (referee) ; Veselá, Mária (advisor)
This bachelor thesis focuses on antioxidant and biological active compounds present in green tea extracts. Green tea is a rich source of antioxidants and it has been considered a medicinal beverage in the past. Series of compounds contained in green tea extracts exhibits strong antioxidant effects. The theoretical part of this thesis deals with the history and production process of tea. It also focuses on the description of the most abundant antioxidant and bioactive substances in tea. Three green tea samples from the retail chain were selected in the experimental section, which were further analysed by selected UV-VIS spectrometry methods and then compared.
Sensory evaluation of drinks enriched with extracts of herbs
Scholzová, Kristýna ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
This diploma thesis deals with sensory evaluation of herbal non-alcoholic beverages, being a part of a new product development. The theoretical part provides information concerning chemical composition, health effects, food applications and aroma compounds of the herbs of interest (peppermint (Mentha piperita), sage (Salvia officinalis), St. John’s wort (Hypericum perforatum) and lemon balm (Melissa officinalis). Another topic is a description of sensory methods, requirements and arrangement of the analysis, statistical methods, and also technological processes leading to herbal syrups and beverages production. The practical part comprises sensory analysis of a few, newly designed, formulas of one-component and two-component alcohol free herbal beverages. The sensory panel consisted of 40 students of master's and also doctoral study programme at Faculty of chemistry, University of Technology Brno. Four subsequent experiments are introduced, each of them consisting of a few sensory tests and including corresponding sensory forms attached. The sensory tests arrangement was based on currently valid Czech Technical Standards, using a ranking, descriptive, paired comparison, sensory profile testing and scaling methods. For the purpose of statistical evaluation, Friedman, Kruskal-Wallis, PCA and Faktor analysis were used. Level of abilities and sensory experience of panelists were found comparable to consumer testing. The results include sensory characteristics of all of the beverages tested. In general, the one-component beverages were preferred to the two-component beverages and the additive colouring with aronia concentrate wasn´t found any benefitial, from the sensory point of view. The consumer questionnaire proved all of the samples to be very promising, but based on the sensory results, we would consider the mint and the sage-mint beverages being the most potentialy applicable samples.

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