National Repository of Grey Literature 158 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Characterization and optimization of sensory quality of jelly sweets
Knotek, Vojtěch ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelor thesis focuses on monitoring and optimization of moisture of starch during jelly sweets processing. The theoretical part focuses on technology of manufacturing jelly sweets and description of raw materials needed for production. The methods for measurement of starch moisture are briefly described. The experimental part focuses on stabilization of moisture of starch during jelly sweet processing, specifically when pouring gelatinous mass into starch forms. The drying scale method was used to measure starch moisture. Recommended starch moisture is up to 8 %. During the two-month measurement, this value was always 0.5 % higher. On the basis of the results of this work, slight modification in the starch drying was made. This led to a reduction in starch moisture but not yet optimal.
Optimization of echinacea drops production technology
Boberová, Jana ; Vespalcová, Milena (referee) ; Zemanová, Jana (advisor)
This diploma thesis deals with the production of herbal drops from Echinacea and the determination of the content of selected active substances. In the theoretical part, the taxonomic classification of echinacea, its botanical characteristics and growing conditions are mentioned. The history of cultivation and uses of this plant are also mentioned. An important chapter of the theoretical part is the chemical composition of the plant and differences in composition between individual cultivars of Echinacea. Methods for obtaining active substances and their determination are also mentioned. The last chapter is devoted to the technology of production of echinacea drops. In the experimental part, the extraction was optimized for dried flowers and roots of E. purpurea. The following extraction system was determined for the flowers: 40% ethanol, time 6 hours, weight to solvent ratio 1:10 and room temperature. For the roots, 20% ethanol and a time of 24 hours, a ratio of 1:10 and room temperature were evaluated as the best conditions. Furthermore, the best extracts were prepared, in which the content of total phenolic substances was set at 0.799-0.839 mg/ml, then the antioxidant activity was determined in the range from 116 to 242 µg T/ml, and finally the analysis of aromatic substances was performed by HS-SPME-GC-MS. Two commercial samples were also tested to compare the prepared extracts.
Sensory evaluation of different types of meat products
Lanžhotská, Aneta ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
The diploma thesis deals with sensory evaluation of selected types of meat products, specifically sausages. Different types of sausages, which contained added chemicals and spices, were compared. The theoretical part describes the properties of meat and meat products and the basic technological procedures used for their processing and production. Furthermore, added substances and spices, which are often considered as flavorings or preservatives, were characterized. The principles of correct performance of sensory analysis and sensory perception of food were also presented, which include a description of the sensory workplace, sample preparation, its implementation, procedure and various evaluation methods used. The experimental part describes the specific work tools used and the conditions under which the evaluation took place. A total of 12 types of sausages were evaluated, 7 of which came from meat production and 5 were prepared in the laboratory of food chemistry at Brno University of Technology. The differences between the samples of sausages, which differed in content and type of added chemicals and spices, were clearly shown using ray graphs. Then the Grubbs test was used, which excluded outliers from the final evaluation. These values were further excluded from further evaluation. The Kruskall-Wallis test was used to distribute the resulting mean values and to determine whether there was a statistically significant difference in sensory evaluation between the results. An appendix to the Kruskall-Wallis test Dunn's test was used to divide the resulting values into given groups according to statistically significant difference and similarity. The analysis of the main components of the so-called PCA was used to find the differences and similarities of the samples included in the groups.
Study of selected technological properties of licorice mass
Gajdušek, Martin ; Vítová, Eva (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis deals with the study of selected technological properties of liquorice matter. By microscopic observation it was found that at a content of more than 10% of the boiled starch grains or more than 30% of the non-swollen grains, the mass does not achieve the desired properties for further processing. Technological loss during drying depends mainly on time, but also on location in the oven, both in height and space. The highest technological loss was achieved mainly in the highest positions in the oven. By liquid chromatography was determined 11.8% glucose, 9.2% fructose, 23.3% sucrose in liquorice mass prior to cooking; 11.9% glucose, 9.4% fructose, 22.6% sucrose in cooked matter; 12.7% glucose, 10.8% fructose and 20.1% sucrose in dried liquorice products.
The effect of temperature and drought on the glutenin proteins content in two genotypes of wheat
Vybíral, Lukáš ; Vespalcová, Milena (referee) ; Hrstka, Miroslav (advisor)
This bachelor thesis deals with the influence of water and temperature deficiency on protein content of gliadin fraction and on glutenin/gliadin ratio in two wheat varieties. The varieties selected for the experiment are called Pannonia and RGT Reform. Samples were cultivated at three different temperatures, 26 °C, 32 °C and 38 ° C, and irrigation was checked at the time of flowering. For wet-grown samples, the soil had a moisture content greater than 70 %, and drought-grown specimens grew on soil with a moisture content not exceeding 30 %. After harvest, the grains were ground into flour and glutenins and gliadins were extracted from the individual samples. SDS-PAGE was used for separation and protein quantification was performed by computer densitometry. A significant effect of the variety on individual gluten proteins was found. In the Pannonia variety, it has been found that the interaction of higher temperature and drought has no major effect on glutenin content and glutenin/gliadin ratio. The RGT variety was significantly affected by these conditions, resulting in a decrease in glutenin content and a significant change in ratio. In both varieties, the glutenin content was higher when cultivated at higher humidity but only at two higher cultivation temperatures.
Study of the antioxidative potential of selected fruit marcs
Havlíčková, Barbora ; Zemanová, Jana (referee) ; Vespalcová, Milena (advisor)
Subject of this bachelor thesis was antioxidant activity of selected kind of fruits. Among selected kinds were the marc of red and white grapes, moldings from red elderberry and aronia. Two species of made capsules from marcs of white grapes and aronia were also subjected to analysis. Results of this bachelor thesis are summarized to four chapters. The first chapter compares the water content of drying at 40 ° C and 105 ° C. In the second chapter, the results of extraction in different proportions of solvent mixture ethanol - water and results of extraction in prepared artificial gastric juice are discussed. As a result, the water – ethanol mixture was a more effective solvent than artificial gastric juice. The third chapter deals with the results and discussion of the determination of the total content of phenolic substances. For the solvent mixture, the largest amount of polyphenols in the red vine marc was determined to be 43,56 mg.g-1, while in gastric juice the largest content in the elderberry was determined to be 11,89 mg.g-1. Capsules were also extracted in gastric juice, and 2,53 mg.g-1 was found in aronia tablets, while 5,93 mg.g-1 in white grape tablets. The last chapter compares the results of TAA measurements using the TEAC and EPR methods. The EPR method was more suitable for much diluted solutions than the TEAC method. The results of this work show that there is a large number of polyphenols and other antioxidants in the moldings that affect the overall antioxidant activity. Marcs have great potential for use as natural dyes or can be used to make a food supplement.
Study of the quality of oilseeds in bread products
Fučík, Jiří ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This bachelors thesis focuses on analysis of crude oils pressed from oil seeds commonly used in bread products. Analysis of oils is made on different heat treated samples of seeds and commercial available oils. In the theoretical part is described the bread-making technological steps and processes, characterized oil seeds used in bread-making and oils from these seeds. In addition there is a description of experimental techniques and used types of quantitative analysis: saponification number, acidic number, ester number, iodine number and peroxide number. In the experimental part was analysed in total three samples of commercial available oils (flaxseed, sesame, sunflower) and three samples of oils pressed from fresh oil seeds (flaxseed, sesame, sunflower). Seeds were also baked in the bread, pressed and analysed. Results of each sample preparation phase was compared and possible change justified.
Study of natural substances of ginger
Dobiáš, Vojtěch ; Vespalcová, Milena (referee) ; Veselá, Mária (advisor)
The aim of this study was to determine the quantity of natural substances in ginger. Extracts from organic ginger tea and ginger rhizome were prepared using three different solvents. Antioxidant activity and the content of polyphenols and flavonoids were determined spectrophotometrically. Effects on bacterial growth of the extracts were studied against bacteria Bacillus cereus and Serratia marcescens by agar well diffusion assay. The obtained data showed, that there is a significant amount of difference between the contents of studied compounds in the two extract samples. The highest amount of polyphenols was found in ginger tea with concentration of 0,481 mgml-1, compared to 0,078 mgml-1 found in the ginger rhizome. The tea showed a greater antioxidant activity than the rhizome. Bacterial growth was slightly inhibited only by water extracts of the tea and this was only observed against Bacillus cereus.
Bioactive compounds of fennel
Nentvichová, Aneta ; Vespalcová, Milena (referee) ; Veselá, Mária (advisor)
The aim of this bachelor thesis is to study the bioactive substances contained in fennel, to determine the content of polyphenols, flavonoids and to investigate the antioxidant and antimicrobial activity in aqueous and ethanol extracts of fennel. The theoretical part discusses the characteristics of fennel, its classification in the system, its use and especially the bioactive substances contained in it. The experimental part is divided into two sections, where the first part focuses on spectrophotometric determination of polyphenols, flavonoids and antioxidant activities. In the second part the antimicrobial effects of prepared extracts of fennel were examined. Two microorganisms Serratia marcescens and Bacillus cereus were exposed to the said extracts. Antioxidant activity and relatively high content of polyphenols and flavonoids were found in the extracts in the first experimental part. The second experimental part proved that the antimicrobial effect of the extracts was very low, in most cases almost negligible. Ethanol extracts showed higher antimicrobial activity, while hot water extracts found to support the growth of Bacillus cereus.
Basic chemical characteristics of cranberry juice
Cao, Ha Thuy ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis is about lingonberries and cranberries. It is mainly about berries which were used for chemical analysis. The berries are from the Research and Breeding Institute of Pomology Holovousy Ltd. and they have delivered six cultivars of lingonberries and three cultivars of cranberries. There is a research of general information about classification, botanical description, important chemical substances such as vitamins, natural colorants and products made in the industry. Furthermore there is descriprion of chemical methods for basic analysis. The next part of bachelor thesis is about how all these methods were applied to berry juice. What instruments and chemicals were used. First assessment was profit of juice which was about 50,00–60,00 %, but lingonberry Runo bilawskie has at least 31,49 % and cranberries have less profit too. Total solids were determined in the range of 11,40 % (Pilgrim) to 18,50 % (Runo bielawskie) and solitable solids are in range of 10,00 % (Pilgrim) to 16,08 % (Korál). Lingonberry contains more reducing sugars (8,81–12,92 %) than cranberry (7,90–9,03 %). Titratable acids are about 32,04–49,60 mmol.l-1 for lingonberry and about 55,40–60,67 mmol.l-1 for cranberry. The measurements show that pH of both berries are about 3. The most phenolic substances are found in range of 2187,11–3476,75 mg.l-1. Berries content anthocyans colorants in range of 54,91-65,29 mg.l-1 and the most in cranberry. All results are shown in charts and in the end there is a discussion and conclusion about methods and results.

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