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Analysis of the rheological properties of vegetable oils and their components
Divílek, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This Master’s thesis is dealing with theoretical analysis of vegetable, mineral oils and synthetic fluids, and with measuring of density and viscosity of selected samples of electric insulating fluids. The main part of the thesis is focused on vegetable oils and their elements called fatty acids. Those are more detail described in separate capitols. In those capitols is described their utilization in engineering practice with focus on energetics, where vegetable oils are used in larger scale. In experimental part of the work is measurement of density and dynamic viscosity. Viscosity was measured on two different machines, first the Hoppler viscometer and on vibrating viscometer. Results of these measurement are evaluated in tables and graphs.
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Dielectric Properties of Vegetable Oils for Electrical Engineering
Spohner, Milan ; Mejzlík,, Miroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation thesis deals with the analysis of prospective environmentally compatible electrical insulating fluids for electrical engineering in relation to their chemical structure. The thesis starts with the overview of the current state of the art and of the latest trends in the use of synthetic and biodegradable natural oils. In the experimental part were studied these oils: mineral oils, rapeseed oil, sunflower oils, soybean oil, methyl oleate, peanut oil, MCT oil, castor oil and other. Dielectric properties were measured using LRC meter Agilent 4980A including dielectric liquid test fixture Agilent 16452A and also by the Novocontrol Alpha-A analyzer. Electrical properties are presented in the frequency range 10 mHz – 1 MHz range in the temperature interval 253 K to 363 K. The work goes on with the study of the suitability of individual oils for lower temperature, including the impact of the chemical structure and formulation on electrical properties.
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Dielectric Properties of Vegetable Oils for Electrical Engineering
Spohner, Milan ; Mejzlík,, Miroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation thesis deals with the analysis of prospective environmentally compatible electrical insulating fluids for electrical engineering in relation to their chemical structure. The thesis starts with the overview of the current state of the art and of the latest trends in the use of synthetic and biodegradable natural oils. In the experimental part were studied these oils: mineral oils, rapeseed oil, sunflower oils, soybean oil, methyl oleate, peanut oil, MCT oil, castor oil and other. Dielectric properties were measured using LRC meter Agilent 4980A including dielectric liquid test fixture Agilent 16452A and also by the Novocontrol Alpha-A analyzer. Electrical properties are presented in the frequency range 10 mHz – 1 MHz range in the temperature interval 253 K to 363 K. The work goes on with the study of the suitability of individual oils for lower temperature, including the impact of the chemical structure and formulation on electrical properties.
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Sekundární metabolity sóji a jejich význam v potravinářství
Hučíková, Dagmar
The bachelor thesis focuses on secondary metabolites in soy and their importance in the food industry. Soy is one of the most nutritious foods. In the first part of the thesis basic information on soy and soy products are generally described. The next chapter deals with secondary metabolites. Here are described individual groups of secondary metabolites, their chemical structure, occurrence and amount in soy beans and foods. Another part is devoted to the methods of the determination of the secondary metabolites. The last part describes the biochemistry of secondary substances.
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The influence of time in feed enrichment with unsaturated fatty acids to selected parameters of pig carcass value with regard to the fatty acid composition of intramuscular fat
Pantoflíček, Jiří ; Čítek, Jaroslav (advisor) ; Miloslav, Miloslav (referee)
The thesis aims to evaluate the impact of aliment with higher contents of unsaturated fatty acids, consumed for a different period of time, to utilitarian attributes of pigs before a slaughter, with respect to the composition of fatty acids in the intramuscular fat of tested animals.
The factors that influence the quality of meat are interior, exterior and technological. Among the qualitative markers of quality of meat we rank the share of meat and fat, acidification rate, color, viscosity, contents of intramuscular fat (marbling), smell, taste, juiciness and delicacy. Together with hygienic and nutritive attributes, consumers and processors consider these technological and sensory aspects to be the most important.
The ultimate goal of this thesis is to compare the impact of different length of feeding soy oil on parameters of pork meat quality and growth.
However, the interference of growth attributes was inconclusive and the test result came similar in different groups of tested pigs.
What was influenced by adding the soy oil into the feed is the fatty acids profile. The contents of fatty acids remained unchanged in every test group. Over time the content of monounsaturated fatty acids decreased. The most significant change occurred in representation of polyunsaturated fatty acids, which increased in the test groups with longer period of feeding with enriched feed, mostly at the expense of monounsaturated fatty acids.
The differences between the test groups of pigs were statistically inconclusive; therefore the soy oil enrichment did not worsen the technological parameters of meat and fat quality.
The longer period of feeding the soy oil enriched feed led to significant increase in polyunsaturated fatty acids. According to the findings, adding the soy oil into the feed will have no effect at all if done short time before the slaughter.
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Effect of linoleic and α-linolenic acidis in pig nutrition on quantity and quality of intramuscular fat of pork with emphasis on the n-6/n-3 PUFA-spectrum
Vehovský, Karel ; Stupka, Roman (advisor)
Human nutrition is a function of nutrients' intake from food. The essential nutrients needed by the human body to produce energy, growth and repair of cells, tissues and organs and which accepts in the human diet, are fats. They are obtained from plant or animal sources. Especially animal fats are often ranged among the unpopular food components. Czech Republic is a country with traditionally high consumption of pork. Recently, about healthy foods greatly increase the interest. These include some animal products having an altered composition of fatty acids in fats. The content and composition of saturated and unsaturated fatty acids in human nutrition are important for protecting of human health. The high content of saturated fatty acids in foods and unfavorable ratio between the n-6 and n-3 fatty acids may be the cause of many diseases, especially cardiovascular diseases. Fats in the diet should contain saturated, monounsaturated and polyunsaturated fatty acids, in a ratio of about 1: 1.4: 0,6. From a health perspective, the most important are the n-3 polyunsaturated fatty acids. Animal fats, however, contain sufficient n-6 polyunsaturated fatty acids, n-3, however, a little. Pork meat quality from the viewpoint of fatty acids composition is currently not very favorable. Significant effects on the fatty acids profile of animal fats have the fats in the feed. It is thus the possibility of by using the diet to influence the composition of fatty acids in the fat in pig. The work is focused on the possibility of influencing the fatty acids composition of pork intramuscular fat using supplementation of different sources and different feeding techniques of unsaturated fatty acids in the feed in pigs. In the experiment, as a source of unsaturated fatty acids the supplement of the rapeseed or soybean oil was used. The results demonstrate that the above unsaturated fatty acid sources significantly changes the fatty acid composition of intramuscular fat.
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Analysis of the rheological properties of vegetable oils and their components
Divílek, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This Master’s thesis is dealing with theoretical analysis of vegetable, mineral oils and synthetic fluids, and with measuring of density and viscosity of selected samples of electric insulating fluids. The main part of the thesis is focused on vegetable oils and their elements called fatty acids. Those are more detail described in separate capitols. In those capitols is described their utilization in engineering practice with focus on energetics, where vegetable oils are used in larger scale. In experimental part of the work is measurement of density and dynamic viscosity. Viscosity was measured on two different machines, first the Hoppler viscometer and on vibrating viscometer. Results of these measurement are evaluated in tables and graphs.
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