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Monitoring of inorganic contaminants in moravian white wines
Šebek, Richard ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis is focused on monitoring of selected inorganic contaminants, especially metallic elements and macro elements, in Moravian white wines. The aim of this thesis is to compare the element composition of wines according to the geographical origin, different production system and vine varieties. Two spectrometric techniques were used for elemental analysis of wine samples: Inductively coupled plasma with mass spectrometer and inductively coupled plasma with optical spectrometer (ICP–MS and ICP–OES). Evaluation of the results was carried out using statistical method of variance analysis (ANOVA). Vanadium, copper, lead and magnesium were evaluated as statistically significant in at least one Moravian sub-region. No statistically significant results were found in other comparisons.
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Content of risk elements in food for dogs and cats
Hrabalová, Karolína ; Slavíková, Zuzana (referee) ; Diviš, Pavel (advisor)
This bachelor's thesis deals with the determination of risk elements, namely mercury, arsenic, cadmium and lead in dog and cat food. The concentration of mercury was determined using the AAS technique, and the concentration of arsenic, cadmium and lead was determined by the ICP-MS method after microwave decomposition of the samples using mineral acids. A total of 30 feed samples were analyzed. In most samples, the concentrations of monitored elements were lower than the maximum permissible values given by the EU Commission Regulation, two samples did not meet the requirements of the regulation. The concentration of risk elements in the feed, except for arsenic, did not depend on the type of meat used in the feed. Feeds containing fish meat showed demonstrably higher concentrations of arsenic than feeds with other meats. Due to the relatively low proportion of meat in feed and due to the overall lower concentrations of risk elements in meat, it can be assumed that the vegetable or other component of the feed, or the technology of feed production, is responsible for the increased concentration of risk elements in feed.
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Measurement of viscosity of suspensions during wheat bran processing
Koukal, Jan ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the assessment of the viscosity evolution of wheat bran suspension during alkaline hydrolysis. Wheat bran is a widely produced low-cost by-product of the milling industry. Due to its composition, bran is a suitable substrate for biorefining and involvement in the circular economy. However, during processing, viscosity development occurs, which greatly affects the energy requirements for processing. The temporal evolution of viscosity during alkaline hydrolysis was determined using a rotational rheometer at constant shear rate. Viscosity was assessed as a function of NaOH concentration, temperature and bran ration. Furthermore, the evolution of viscosity was measured during alkaline extraction of proteins. The highest viscosity was measured in a 0.2 M NaOH system at 30 °C with a bran to hydroxide ratio of 1:10. Its value was 0.991 ± 0.010 Pa.s. Based on the theoretical part and the data obtained from rheological measurements, the design of a stirred reactor for wheat bran processing on an industrial scale was carried out. It is a vertical cylindrical vessel with a total volume of 10 m3. The vessel is equipped with three Chemineer HE-3 hydrofoil impellers mounted on a vertical shaft. The power input of the agitator was calculated at 2.8 kW and compared to a conventional 4-blade, 45-degree pitched blade turbine, the chosen design was four times more efficient.
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Effects of the addition of fortified wine in the production of pates on the sensory quality of the product
Kmeť, Jan ; Slavíková, Zuzana (referee) ; Mikulíková, Renata (advisor)
The aim of this thesis is to evaluate effect of addition of fortified wine on sensory quality of pâté. Thesis deals with preparation of fortified wine enriched pâté and their suitability for consumption. Main ingreditents, mainly meat and fortified wine are described in theoretical part. Furthermore, the technology of pâté production, methods and conditions of sensory analysis are also listed in this thesis. A total of nine types of pâté were prepared, eight of these pâtés contained different amouts of selected fortified wines. By evaluation of thermosterilation process, prepared pâtés were suitable for consumption. The sensory analysis showed us that addition of fortified wine mailny affects appearence, colour and flavour of product. Most preffered were pâtés without addition of fortified wine. Pâtés that contained Santa Cruz pink porto Rosé wine and Czech liqour wine Agni were well rated.
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Study of the profile of sensory active compounds in Moravian wines
Havlíková, Markéta ; Slavíková, Zuzana (referee) ; Vítová, Eva (advisor)
The subject of this bachelor thesis was to determine and compare the profile of volatile substances in selected samples of red wines originating from the Moravian wine region. Wines of three varieties were analyzed – Frankovka, Zweigeltrebe and Pinot Noir. The HS-SPME-GC-MS method was used for the determination of volatile substances, part of the work was the verification of its linearity (R2 in the range of 0.829–0.999). A total of 80 volatile aromatic active substances were identified in the samples, of which 23 were subsequently selected as the most represented and characteristic of the monitored varieties. The main attention was paid to the Frankovka variety, which showed variability in the content of the monitored compounds not only within the variety, but also within the monitored years (2017 vs. 2018).
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Possibilities of using moringa oleifera in the production of meat products
Richterová, Nikola ; Slavíková, Zuzana (referee) ; Mikulíková, Renata (advisor)
This bachelor thesis deals with the addition of moringa oleifera and its influence on the sensory quality of meat products, specifically wine sausages. The theoretical part describes the meat, the division of meat products, and the basic technological operations leading to their production. Furthermore, wine sausage, its composition, and production technology are characterized. The description of moringa oleifera and its chemical composition follows. The conclusion of the theoretical part is devoted to sensory analysis, conditions for sensory assessment, and the main methods of this analysis. The experimental part is focused on the production of wine sausages with various additions of moringa oleifera and subsequent sensory evaluation of these sausages. When assessing the sensory quality of the sausages, the samples were evaluated according to their appearance, smell, taste, and texture. A total of 25 evaluators, who were representing ordinary consumers, took part in the sensory evaluation. The content of lipids and fatty acids in the samples of sausages was analyzed by gas chromatography. A separate sample of Moringa was also analyzed by gas chromatography. The polyphenol content of the samples was determined by liquid chromatography. Using the Kruskal-Wallis test, it was found that there were statistically significant differences between the samples. The sample with the lowest addition of moringa and the sample without moringa were assessed very similarly and were evaluated as the best. While the sample with the highest moringa addition was rated the worst in all assessed categories.
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Determination of hydroxymethylfurfural in honey
Dohnalová, Barbora ; Slavíková, Zuzana (referee) ; Diviš, Pavel (advisor)
Honey is a valuable food of a natural nature that can be subject to adulteration for higher profits. One method of detecting this adulteration may be to determine hydroxymethylfurfural, the formation of which is promoted by heating. The theoretical part of the thesis deals with the types of honey, their origin, and the possibilities of their falsification. HMF, its occurrence and use and methods for its determination are also described. The practical part is devoted to the description of the experiment such as sample preparation, measurement and evaluation. The HPLC (high performance liquid chromatography) method was used to determine HMF in honey, which can be used to determine even very low concentrations. There were five samples for the experiment, four of them directly from the beekeeper and one from the retail chain. All samples were compared for HMF content. The highest concentration of HMF was determined in a sample of commercially available honey. In domestic honeys, the HMF content increased with the age of the honey. The content of HMF in all honeys complied with Decree No. 76/2003 Coll.
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Possibility of utilization of solid waste from spent coffee grounds rafination for agricultural purposes
Slavíková, Zuzana ; Vespalcová, Milena (referee) ; Pořízka, Jaromír (advisor)
The main focus of this diploma thesis is the utilization of spent coffee ground (SCG) and its biorefinery products in agriculture primarly as a prospective organic fertilizer. The study verifies an influence of the addition of native SCG as well as its acid hydrolysed, defatted and oxidized forms to experimental clay soil on chemical and physical properties (ph, conductivity and mineral content). Growing experiments were realized by using Lactuca sativa to detect positive or negative effects on growth. Samples of basic soil and soil with the addition of commercial NPK fertilizer served as a reference to measuring data. Measurements showed that addition of SCG and products of its biorefinery to the soil caused a decrease of pH and an increase of conductivity of soil samples. Significant increase of extractable calcium, magnesium, manganese and moderate increase of potassium content was detected. 2 % addition of SCG to soil had no impact on plants growth. The number and visual appearance of lettuces were comparable with plants in basic soil. No seed on acid hydrolysed samples germinated, which was caused by an increase of conductivity and sulphate content in these samples. In defatted and oxidized samples the early germination and the highest number of lettuces was observed. The low content of phosphorus in all soil samples had a great impact on growth rate and visual appearance of cultivated lettuces. In comparison with soil with NPK addition, lettuces in samples with SCG and its form had a pink-grey colour and lower growth.
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