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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Volatilní látky v šumivých vínech

Skýbová, Markéta January 2014 (has links)
Volatile substances are responsible for the fragrance features not only sparkling wines. According to research there are more than 400 compounds.In this thesis is shortly mentioned technology of the sparkling wines and sparkling wines in the Czech Republic. Most of the work is devoted to the characterization of volatile substances found in sparkling wines. In the experimental part, 26 of samples were evaluated by sensory evaluation but the priority is given to volatile substances. By GC-MS were measured 65 volatile substances, which were subsequently evaluated. The focus is primarily on substances for which there is a decline during aging (amyl acetate), or growth (diethyl succinate, furfural, etc.). Volatile substances are evaluated not only by producers, but also by country of origin and in the last chapter is compared between the technology productions.
112

Vplyv fortifikácie v rôznych štádiách macerácie/fermentácie na antioxidačné vlastnosti vín

Holovic, Michal January 2014 (has links)
Diploma thesis dealt with studying and evaluating the impact of fortification in different stages of maceration/fermentation on antioxidant properties of wine. The literary part of the work was clearly described chapters on various production methods and types of fortified wines, different classes of phenolic substances present in wine and study of antioxidant activity of wine and methods of assessment. In the practical part, were selected three blue grape variety from which it was successively produced 9 samples fortified wines. Time fortification took place in three different stages of maceration. The first was the fortification to the must before the start of fermentation, a second fortification during the fermentation of sugar - fermentation to about 7 % by volume alcohol, and the third fortification after fermentation in young dry wine. Fortification was carried out by adding the calculated amount of spirit in the volume of wine or must, at the same level of spirituosity all the resulting wine samples. After some time joining the distillate was carried out basic analysis of wine samples and determination of the profile of phenolic compounds. Spectrophotometric method was further assessed total content of phenolic compounds, flavanols, anthocyanins and antioxidant activity, which was determined by two different methods. Basic analysis and spectrophotometric measurements were performed in triplicate and the results were averaged. Samples of fortified wines were finally sensory evaluated participation of 12 tasters, and all the results summarized in tables and graphs, statistically evaluated and described in drawing conclusions for practical use.
113

Olfaktorická interakce člověka a dřeva

Shorná, Radka January 2015 (has links)
Theoretical part of this thesis, deals with issues of odor substances found in the interior environment with special focus on solid wood odors and their relationship with VOCs. Although there is no direct impact of odors on human health, they can severely affect physical and mental well-being of the individual and lead to secondary complications and accidents. Subjective evaluation of odor perception is one of the factors that can be decisive when choosing furnishing elements. It is assumed that the human and wood olfactoric interaction could play an important role in marketing strategies of furniture manufacturers and distributors. Therefore, there was also practical part to this project, which deals with subjective odor evaluation of solid wood samples using sensory analysis. Then evaluation of short questionnaires. The obtained data were used to finalize results applicable in practice and useful for further olfactory research. Final part of this thesis deals with possible practical applications of those results, different means of aromatisation and their concrete rendering.
114

The study of individual phenolic compounds with antioxidant properties in grape berries and wine produced from new interspecific varieties under the conditions of South Moravia, Czech Republic

Khafizova, Asiya Askhadovna January 2012 (has links)
Nowadays the study of phenolic compounds and their content in food is of great interest due to their versatile capabilities, and above all their beneficial influence on human health. According to numerous research works phenolic compounds are able to decrease the level of cardiovascular diseases, and they have bactericidal, fungistatic, antioxidant and vitamin properties. Most authors agree that vineyard site, as a combination of soil-climatic conditions, and rootstocks have a significant influence on accumulation and distribution of phenolic compounds. That is why the influence of different vineyard site and rootstocks on content of various phenolic compounds and spectrophotometric indexes of must and wine of new interspecific grape varieties was studied. The results of our research allowed us to choose the best rootstock and vineyard site for each variety. The comparison with control varieties showed that the influence of the year on content of individual phenolic compounds is more prominent than the influence of studied factors (vineyard sites and rootstocks). The knowledge in that area could help to select and recommend certain vineyard sites and rootstocks for those varieties. The choice will be based both on the quality of must and wine and on the potentially positive influence on human health. The correlation of the antioxidant properties with the principal polyphenols showed that individual compounds are weakly associated with all antioxidant parameters, suggesting that the expression of antioxidant activity is rather a consequence of synergism between various phenolics, and it is not simply attributed to specific constituents. On the other hand a strong positive correlation of AAR in grape juice and catechin content was established, these data indicate that catechin is likely to play a major role in antioxidant activity of grapes.
115

Pomologické hodnocení vybraných méně pěstovaných jádrovin

Sikorowská, Monika January 2015 (has links)
This diploma thesis is about some less grown pome fruit species like Rowan, Service Tree, Hawthorn, Medlar, Crataegomespilus Simon-Louis and Sorbopyrus Scheele. Thesis is focused on the observation of individual phenophases for this species and recording of the numbers of flowers and fruits on them. Work is focused mainly on pomological description of mentioned species and variety. Contain statistically processed data about fruit size. In experimental part of the thesis are values for vitamin C content, carotenoids and minerals (K, Na, Ca, Mg) content, which were also valuated statistically. The result outcome of this thesis is chosen species and cultivar for the climate conditions of Czech Republic.
116

Hodnocení experimentálních linií ječmene z hlediska tolerance k suchu a rezistence vůči padlí

Slabá, Veronika January 2015 (has links)
Drought is considered as one of the most important abiotic stress factor, which can cause a severe impact on agriculture. The development of new cultivars of barley is therefore more focused on improving of abiotic stress tolerance to drought, as well as on maintaining of good health status, appropriate yield levels and quality parameters. This work was aimed at evaluation of barley cv. Tadmor, which is specifically adapted to drought and can be potentially used as a source of drought tolerance in barley breeding programmes. F5 generation lines derived from reciprocal crosses between cv. Tadmor and cv. Jersey (advanced European spring malting barley) together with parent cultivars were cultivated at two sites (Brno, Žabčice). The assessment was aimed at traits associated with yield (thousand grain weight - TGW, percentage of sieving fraction over 2.0 mm, grain yield per plant) and quality (protein and starch content). The effect of water-limited conditions at Žabčice site was demonstrated particularly in the TGW and the percentage of sieving fraction over 2.0 mm, while the lines from Tadmor x Jersey cross sustained the stress significantly better than those from Jersey x Tadmor cross. The lines grown in Žabčice reached in average a higher level of protein content and a lower level of starch content. The significant effect of genotype was detected only in protein content and was non-significant for starch. The reaction of selected lines on osmotic stress was studied in and independent experiment under controlled conditions. The plant stress reaction was evaluated according to changes in osmotic potential in leaves and accumulation of proline. Lines with Tadmor as a female parent showed higher values of osmotic potential in comparison with those derived from the reciprocal cross. The increase in osmotic potential under stress was strongly associated with the content of proline. The last part was focused on evaluation of susceptibility to powdery mildew caused by Blumeria graminis. The symptoms of powdery mildew on experimental lines were assessed in field and the lines, which were classified as resistant/susceptible, were further analysed for the presence of mlo allele. According to the results all resistant lines carried mlo9. With regard to all evaluated parameters, positive reaction on physiological drought stress and genetically controlled resistance against powdery mildew two lines can be recommended for further work.
117

Mikrobiologie sýrů ošetřených bioaktivními látkami za účelem prodloužení jejich trvanlivosti

Nedělová, Barbora January 2015 (has links)
The theoretical part is focused on the production, distribution, and defects of cheese made from cow's milk, and its importance in nutrition. There are also described important species of beneficial and pathogenic microorganisms as well as the fight against undesirable microorganisms. In the last part of the literature review there are characteristics of selected groups of bioactive substances. The practical part of the thesis deals with analysis of microbiological fresh cheeses treated with natural substances due to their durability. Within microbiological analysis were determined selected groups of microorganisms - total number of microorganisms, lactic acid bacteria, psychrotrophic microorganisms, coliforms, enterococci, fungi and yeasts. Samples of fresh cheeses were treated with an extract of peppermint (Mentha piperita L.), mugwort tarragon (Artemisia dracunculus L.) and pumpkin seed oil. Subsequently, they were packed in an atmosphere free, containing CO2 or N2. The results showed that at a storage temperature of 8 ° C neither the used natural raw materials nor the atmosphere affects the shelf life of fresh cheeses.
118

Sledování těkavých látek v granulovaném krmivu pro psy / Monitoring of Volatile Compounds in Dry Dog Foods

Šímová, Lenka January 2016 (has links)
The aim of this study was to explore the influence of volatile compounds in dry dog food on its attractiveness for dogs. The assumption was that the attractiveness is mainly affected by volatile compounds presented in the feed. This study brings overall information about dog´s digestive system and its nutritional requirements with the summary of available feeds including the production process and list of the customary ingredients. A survey of the most common volatile compounds including appropriate analytical methods is also part of this study. A feed preference test was performed in experimental part of this study. The preference ratio of two dry dog diets was set to 21:79 % that shows clear preference for one of the feeds. Chemical analysis using gas chromatography-mass spectrometry revealed distinctions in the volatile compounds profile of the tested feeds. 3-tert-butyl-4-hydroxyanisole that is part of synthetic antioxidant BHA was identified to be the main volatile compound that could possibly be responsible for feed preferences observed in this study.
119

Vliv huminových látek na vlastnosti masa brojlerových kuřat / Influence of humic substances on the broiler chicken´s meat

Novák, Tomáš January 2016 (has links)
Due to great popularity of the chicken meat, the breeders try to improve yield of meat and its quality parameters, which leads to the application of various food additives such as those based on humic compounds. Those humic matters are used for their positive influence over the immunity system, metabolic functions and adaptability of the livestock organisms. Literature review sums up the experience with broiler chicken breeding and feeding. Further it deals with meat composition and its characteristics. The last part contains information of humic compounds and their influence over the live organism and compares the findings about the application of humic preparation into the livestock food portion. Practical part of this thesis researches the influence of humic preparation Humafit over the qualitative and quantitative parameters of the broiler chicken meat. Two groups of chicken were observed, experimental one and control one. Feeding of these two groups was held at the same time, whereas the experimental group was being fed with 200 ml of Humafit per 1000 l of supply water from 10th to 20th day of feeding. The research did not prove statistically important differences (p > 0.05) in chicken corpse weight such as in weight of each parts of the corpses. Differences in the protein content in the breast muscle were also not statisticaly demonstrative such as pH value of the breast and thigh muscle. Total amount of heme pigments in breast muscle of the experimental group was higher and this difference was statistically important (p = 0.049). The breast muscle of chicken in the control group showed up higher binding capacity for water, this difference was statistically important (p = 0.041). This finding correlates with sensory analysis results (|r| = 0.691), when the panelists rated the meat of the control group chicken as more flavorous. There is disunion among scientific studies in the opinion of humic compounds influence over the livestock organism. It is not possible to make a definite evaluation of humic compounds influence over the meat quality, because qualitative and quantitative parameters of the livestock meat depend on the number of intravital and external factors which can affect the experiment results.
120

Obsah minerálních látek v píci ovlivněný předchozí rozdílnou intenzitou pastvy / The mineral content of forage influenced by previous varying intensity grazing

Pavlů, Klára January 2015 (has links)
The mineral content of grassland is one of the key factors that determine its quality. The aim of the study was to determine the optimal interval for the grazing and the optimal interval for the hay harvest in relation to the nutrient requirements for cattle and determine the dynamics of pasture forage yield and mineral content during the growing season. H0: Previous different grazing intensity has no effect on biomass yield and the mineral content in the following growing season. The experiment was performed on a long term grazing experiment in 2012 -- 2013, where during the growing season biomass samples were taken and subsequently analyzed for minerals (N, P, K, Ca, Mg, Na). The sampling was carried out in treatments that have been since 1998 at the beginning of June mowed and then intensively or extensively grazed. During the sampling period the access of grazed animals to sampling sites was forbidden. Intensive or extensive grazing in the previous grazing season significantly affected the content of minerals and biomass yields. Especially at the beginning of the growing season the contents of N, Ca and Mg were higher in forage, which was in previous years, intensively grazed. After that, the differences between these two treatments were not significant. Diverse grassland with a higher proportion of herbs contained higher levels of calcium and magnesium. Because of lower K concentrations and higher Ca and Mg concentrations in the fodder there was no problem with tetanus ratio (K/Ca + Mg) by exceeding the limit value of 2.2. The present work shows that the optimal term for hay in mesophilic upland grassland the end of May to mid-June. In this time historically the first cut was conducted. After this period there are revealed such changes in the content of minerals, which significantly deteriorate the forage quality. Therefore, if the first cut after mid-June is postponed then compensatory payments under environmental schemes should progressively compensate financially losses

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