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Consumption and species representation of vegetable oils in the daily diet families in the Czech Republic
MARHOUNOVÁ, Milada
The bachelor thesis focuses on consumption and species representation of vegetable oils, fats in the daily diet families in the Czech households. In the theoretical section, I conducted a literary research of available resources regarding to the subject. This section focuses on definition of oils and fats, their chemical composition fats and fatty acids. Well-known and less known vegetable oils with the highest contents of saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, omega -6 and omega -3 fatty acids. Also processing and use of vegetable oils. Importance of fats in human nutrition and nutritional recomendations. In the practical section is described methodology of the research. I chose a questionnaire method to collect the datas. Questionnaire survey focuses on consumption and species representation of vegetable oils, fats in the daily diet families in the Czech households. What are the criteria for shopping of vegetable oils and their usage in the kitchens. Whether people know about positive effescts of omega- 6 and omega -3 fatty acids in human nutrition and also importance to human health. The partial results are characterised and discussed in the conclusion of this work.
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Vitamin D blood level and its relationship to recurrent childhood diseases
HAVLOVÁ, Adéla
"Vitamin D blood level, factors that affect it, and its relationship to reccurent infections" is topic repeatedly discussed in domestic and foreign literature. This topic is a multidisciplinary issue, but it mainly relates to nutrition and sun exposure. The aim of this study is to map relationship of vitamin blood levels in relation to diseases of the respiratory system, vitamin D suplementation, recurrent infections, usage of sunscreen with a protective factor, nutrition and outdoor stay in winter months. The study was conducted on a research sample of preschool children. Two sets of data were used to evaluate objectives and research questions. The first research group consisted of 48 children and had 2 groups. The first group of 21 children was established in the Waldorf kindergarten in Rudolfov and the second group of 17 children was created in a non-state medical facility in Trebon. The first research consisted of 48 children who were tested on vitamin D blood level and filled survey questionnaire. The second research consisted of 61 children who were tested on vitamin D blood level in a non-state medical facility. Some results of this study are contradictory because of inadequate methodology. Positive results have been shown with vitamin D supplementation, higher consumption of liver, eggs and daily intake of vegetable oils.
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Production and characterization of cheese analogues with the addition of vegetable oil
Babištová, Lucie ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This thesis deals with the production and characterization of cheese analogues, ie products in which some of the dairy components are mutually or completely replaced by a non-dairy component. Model samples of fresh cheese and analogues of fresh cheese (standard) with the addition of linseed and rapeseed oil were produced by a standard technological procedure in MENDELU Brno. The content of bound and free fatty acids, volatile (aroma) substances and sensory quality was monitored in the samples. The main focus was to evaluate the effect of added vegetable oil on the monitored parameters. The fats from the sample were extracted with a mixture of diethyl ether and petroleum ether. Fatty acids were converted to methyl esters by boron trifluoride-catalyzed acid esterification and subsequently identified by GC-FID. The analysis found a higher content of fatty acids in cheese analogues in comparison with the control sample, also the content of unsaturated fatty acids increased. The HS-SPME-GC-MS method was used for the identification and semi-quantification of volatile substances (aromatic substances). 56 volatile compounds were identified in the samples; The percentage of individual chemical groups differed significantly, the highest content was found in the control sample. Sensory evaluation was performed using a scale and a serial test. In all of monitored indicators (apparence, color, consistency, smell and taste) the control sample was evaluated as best. As for the analogues the taste and smell of used oils were detected, which was unpleasant for the evaluators. The obtained results show that the addition of vegetable oils increases the nutritional value of cheeses (higher content of unsaturated fatty acids), but reduces their sensory quality and overall consumer acceptability.
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Modern vegetable oils useful in food and cosmetics
Plachtová, Kateřina ; Mravcová, Ludmila (referee) ; Zemanová, Jana (advisor)
The aim of this Bachelor’s thesis was to make a literary research of currently most used vegetable oils in food technology, cosmetics and pharmaceuticals focusing on health benefits, possibilities of use. Two selected modern vegetable oils were specified that are currently a subject of research in respektive fields. The selected modern oils were carrot seed oil and raspberry seed oil. A literary recherche was drawn up dealing with these oils from the perspective of their composition, charakteristics, properties and use in food technology, cosmetics and pharmaceuticals. In the experimental part of the thesis the fatty characteristics of carrot seed oil and raspberry seed oil were determined: acid value, saponification value, ester number, iodine value, peroxide value. Also fatty acids present in the oils were identified and quantified using gas chromatography with flame ionization detector. Fatty acids were analysed as their methylesters. Derivatization was was performer by alkalic esterification using methanolic solution of potassium hydroxide. In conclusion, selected oils were compared in terms of fatty characteristics and fatty acid profiles. Fatty acid composition was also compared to fatty acid composition found in literature sources.
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Sources and current level of consumption of omega-3 fatty acids in the Czech Republic
MERLEOVÁ, Gabriela
The thesis deals with beneficial omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and their beneficial effects on health. Characteristics, properties and appearance of omega-3 fatty acids may explain some of the mechanisms of their effects on human health manifested not only in the treatment and mitigation of some non-infectious diseases of mass occurrence, but especially in the area of preventive action. Theoretic information used in the first part of this work was obtained from scientific and professional publications and periodicals searched in domestic and international databases of scientific and specialist literature. The part of data collection and analysis compares the intake of omega-3 acids in the form of fish dishes prepared for children in the first half of elementary school, aged 7 to 10 years, in randomly selected school canteens or contracted catering in the European Union with the recommendations of Decree 107/2005 Sb. Ministry of Education.
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Study of alternative electroinsulating liquids properties
Bannert, Tomáš ; Hylský, Josef (referee) ; Frk, Martin (advisor)
This bachelor´s thesis is dealing with the study of alternative electrical insulating properties of the materials used in the electronics industry, particularly liquids based on natural esters and especially their constituents in the form of higher fatty acids and esters. The work is divided into theoretical and practical part. The theoretical part deals with the characterization of vegetable oils, their constituents and mineral oils, their comparison in terms of electrical and non-electrical properties and current state of the use of vegetable oils and their constituents in the electronics industry. Further it’s dealing with analysis of diagnostic methods for these characteristics. In the experimental part were analyzed electrical and non-electrical properties of selected samples of vegetable oils, their constituents and mineral oils such as the density, the dynamic viscosity and the complex permittivity and its parts as relative permittivity and loss number. Evaluations of the results of each group are compared with each other.
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Thermal degradation of alternative electrical insulating liquids
Vodička, Tomáš ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
This thesis deals with alternative thermal degradation of electrical insulating liquids. The theoretical part describes the current state of the problem, electrical insulating liquids, their classification and types. There are described properties of electrical insulating liquids, their models of aging and diagnostic methods in accordance with the appropriate standards. In the practical part are chosen by representatives of alternative electrical insulating liquids and there are determined their dielectric characteristics in the initial state. According to the measured values is chosen five candidates for which it is designed and implemented an accelerated degradation test. During the test are measured dielectric parameters of the selected oils. Measured dependencies are mathematically approximated. In conclusion, the results are compared and physically interpreted in view of oxidation stability.
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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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Dynamic viscosity of electroinsulating liquids
Míka, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with persepective environmentally friendly electroinsulating liquids. Important properties of currently used electroinsulating liquids are listed. Physical nature of viscosity of liquids and its temperature dependance are described and methods of its measuring are listed. Also temperature dependance of density is described from physical point of view. Measurement of density and of temperature dependance of viscosity of chosen vegetable and mineral oils was performed. On the basis of this measurement was calulated the activation energy of these samples. Two methods of dynamic viscosity measurement were used for some samples.
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Evaluation of stability of selected vegetable oils
Němečková, Lenka ; Lehocký,, Marián (referee) ; Zemanová, Jana (advisor)
This diploma thesis is focused on issues concerning the stability of selected vegetable oils which are used in cosmetic industry. The stability of eight oils without additives were determined by a differential scanning calorimeter. In the first phase, the temperatures of oil degradation were determined for different rates of heating, i.e. nonisothermal stabilities. They were consequetly used to calculate isothermal stabilities alias induction periods. The calculation of induction periods was completed by using integral isoconversional methods, which applied four different temperature functions. One of the temperature functions corresponded to Arrhenius equation while the others to non-Arrhenius functions. The confrontation of induction periods under standart conditions showed that an optimal temperature function to calculate oil stabilities is one of the non-Arrhenius functions in exponential form. We can state that all oils are degraded by similar, if not the same, mechanism. The specified stabilities, in periods of months, have proved the importance of using stabilizers and other additives in the commercial and technological use of vegetable oils.
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