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Hygienická kvalita mléka
Holá, Kateřina
This work deals with the hygienic quality of milk, the possibilities of its influence in the barn in the process of breeding and in its acquisition. The theoretical part describes in detail the various components of milk, such as proteins, fats, carbohydrates and focuses on hy-giene of the milk before and after milking. There is also described heat treatment of milk, including cattle diseases that affect milk production. In the practical part evaluates the qual-ity of the milk sold in selected farm. Starting from the results of laboratory analyzes of milk, which are assessed according to the season and the state of health of dairy cows.
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Wood Extractive Compounds - Extraction, Chemical composition, Biological activity, Native durability =: Extraktivní látky dřeva: Extrakce, Chemické složení, Biotická aktivita, Přirozená trvanlivost /
Sablík, Pavel
Wood chemical composition research is of significant importance for various fields like wood-manufacturing, food and pharmaceutical industries. Much research work has been motivated by the fundamental knowledge that wood of some tree species demonstrate significantly higher native durability against biological degradation and therefore is much convenient to use in more demanding applications, e.g. in contact with soil or water. This important wood property was assign mainly to presence of extractive chemical compounds or secondary metabolites, produced by wood when heartwood is formed. The presented doctoral thesis aims to find the possibilities of how to utilize extractive chemical compounds found in Black locust (Robinia pseudoacacia L.) as treatment solutions. These can be used to increase the durability of low durable wood species. The experimental part of the presented thesis was carried out using the laboraties and equipment of the Mendel University in Brno, and their external laboratories of research centre in Útěchov. Paper 01 aims to establish methodology for extraction apparatus fexIKA. Describes mainly possibilities for quantitative gains of extractives when using various organic solvents. Within this papers research scope heartwood, sapwood and bark of Black locust were used as the source material. Black locust was choosen mainly due to its extremely high native durability, together with oak considered highest in Central Europe, and for longer term experimental plans and reason. The established methodology for primal solvents (acetone, benzene, cyclohexane, ethanol and distilled water) was the result of this paper. The influence of extraction inputs (particles size, solvent type and temperature) on quantitative and qualitative result of extraction process was the topic for research design presented in Paper 02. In the paper comparable results with literature and established fexIKA methodology were proven. Also the effect of the above mentioned inputs are described and extracted chemical content was identified using HPLC-HRMS technique. The possibility of utilizing chemical compounds obtained, based on Paper 01 extractive methodology, aimed for higher content of phenolic compounds according to Paper 02 results, were the topic of Paper 03. This research paper proves antifungal activity of Black locust (Robinia pseudoacacia L.) and African padauk (Pterocarpus soyauxii Taub.) extracts after impregnation into European beech (Fagus sylvatica L.) sapwood. This wood species is assessed as class 5 (not durable), with an average mass loss result after the durability test of untreated samples 43.6 %. Native durability of European beech wood was significantly improved after impregnation with extractives, mass loss resulted in average 12.7 %. This revalued treated beech sapwood into durability class 3. Paper 04 continues with a study of extractives retention in wood matrix after impregnation whilst introducing adjusted leaching tests. Despite standard EN 84, this research employed miniaturized Bravery wood blocks for impregnation and leaching tests, which were at the end shortened to 144 hours. In order to increase the biologicaly active chemical compounds retention in the specimens, heat treatment was used. The results of the experiment proved the significance between heat treatment and retention.
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Mikrobiologie tepelně ošetřeného mléka
Lidmilová, Jitka
The bachelor thesis solves matters of microbiology of milk. It follows up by microorganisms, which are in heat-treated milk too. The bachelor thesis describes microorganisms, which can cause spoiling of milk, and pathogenic microorganisms. The part of thesis focuses on fight against undesirable microorganisms. In the bachelor thesis is described an experiment, during which some species were determined in samples of milk.
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Způsoby prodloužení údržnosti mléčných výrobků
Piskačová, Martina
This thesis discusses the way to extend the shelf-life of dairy products. The first part focuses on mold spoilage of dairy products, types of microorganisms threatening dairy products and the factors that influence the growth of undesirable microorganisms. The second part focuses on the basic heat treatment during technological processing of dairy products that affect their durability. The final part of the work is focused on the effects of antimicrobial substances in milk and dairy products. Above all, the preservatives, antioxidants and bioactive substances.
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