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Recovery of the method for assessment of fatty acids
Gross, Michal ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
The objective of this bachelor thesis is to verify recovery yield used for determination of fatty acids based on gas chromatography with flame-ionization detection. In the theoretical part, fatty acids and lipids are characterized and extraction of lipidic fraction from food samples with its subsequent adjustments is suggested. Furthermore, the principle and current instrumentation of capillary gas chromatography with flame-ionization detection and standard parameters for validation of the analytical method are specified. In the experimental part, verification of recovery yield of the method for assessment of fatty acids was performed. The used method includes extraction of lipids from a sample in accordance with the standard ISO 1735 regulation and transesterification of both free and bounded fatty acids catalysed by boron trifluoride according to the ISO 12966-2 standard regulation. The produced methyl esters can be effectively determined using gas chromatography with flame-ionization detector. Analysed samples of rapeseed oil and tilsiter-type cheese were purchased in a common food market.
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Isolation and characterizaation of oil from some types of coffee
Vašků, Barbora ; Hoová, Julie (referee) ; Skoumalová, Petra (advisor)
Coffee, extract, oil, phenolic compounds, flavonoids, antioxidant capacity, SPF, critical wavelenght.
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Monitoring the nutritional profile of edible fats and oils after culinary treatments
Chadimová, Markéta ; Vítová, Eva (referee) ; Němcová, Andrea (advisor)
This diploma thesis studies changes in the nutritional composition (especially fat changes) of selected fats and oils after various culinary treatments and during their storage under unsuitable conditions. Fats and oils are classified as so-called triacylglycerols, ie they are composed of glycerol and three fatty acids. It is the fatty acids bound to glycerol that determine the properties of fat and its stability. Eight types of fats and oils (sunflower oil, rapeseed oil, olive oil, coconut oil, linseed oil, butter, ghee and lard) were used for the analysis. The flaxseed oil sample was stored for 3 months in unfavorable storage conditions, ie in the light and in the heat. Other fats and oils were used for frying, baking, stewing, grilling and frying meat and onions. The aim of the work was to compare changes of fatty acids, changes of fat numbers and compare the amount of vitamin E contained in individual oils before and after culinary treatments. The results of the analysis showed that fat samples did not show significant changes in fat numbers, fatty acids or vitamin E after culinary treatments or improper storage. From this I conclude that fats and oils have been exposed to high temperatures and unsuitable conditions for a short time. The largest difference in the composition of fatty acids was measured for sunflower oil, where a higher amount of trans fatty acids was measured after treatment and overall a lower proportion of PUFA was measured than before treatment. As sunflower oil has a high content of polyunsaturated MK and a low smoke point, this result was expected. The highest concentration of vitamin E was found in rapeseed oil.
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Controlled production of polyhydroxyalcanoates by bacterial strain Ralstonia eutropha using different substrates
Šnajdar, Ondřej ; Duroňová, Kateřina (referee) ; Márová, Ivana (advisor)
This bachelor’s thesis deals with production of polyhydroxyalkanoates (PHA) by bacterial strain Ralstonia eutropha. Production of PHA on different substrates has been studied to lower the costs of feedstock. In theoretical part the review has been done about the most important types of PHA, production strains and possibilities of cultivation of Ralstonia eutropha using different substrates. In practical part there has been studied production of PHA on different vegetable oils, including waste oils from different sources (restaurants, homes, food companies). Incorporation of different precursors for copolymer production control was studied too. The highest yields of poly-3-hydroxybutyrate (P3HB) have been achieved using waste oils. For economical and ecological reasons these oils are very suitable substrates. Using concentration 20 g/l of waste rapeseed oil from university canteen there has been produced 13,32 g/l of biomass containing 58,63% of P3HB in 84th hour of cultivation. The highest yield of PHA in precursors study has been achieved applying 1% propanol in 24th hour of cultivation. The PHA increase has been 97%. This PHA was composed from 91% of 3HB and 9% of 3-hydroxyvalerate.
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Porovnání zastoupení mastných kyselin u přírodních a bio jedlých rostlinných olejů
Pevná, Markéta
In my bachelor thesis I am especially focused on the composition of oils. I also write about its importance in a human body and its production process. I describe the structure of fatty acids and the role of lipids in metabolism too. For experimental analysis I chose five different organic and natural oils, which I compare in aspects of fatty acids composition by gas chromatography. From the results of the total fatty acid content it can be stated that almond oil contained 0.97 g/g in organic and non-organic variant, grape seed oil in organic and non-organic variant 0.99 g/g, coconut oil in organic variant 0.33 g/g and nebio variant 0.64 g/g, evening primrose oil in organic variant 0.92 g/g and nebio variant 0.96 g/g and argan oil in organic variant 0.91 g/g and nebio variant 0.98 g/g.
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Monitoring the nutritional profile of edible fats and oils after culinary treatments
Chadimová, Markéta ; Vítová, Eva (referee) ; Němcová, Andrea (advisor)
This diploma thesis studies changes in the nutritional composition (especially fat changes) of selected fats and oils after various culinary treatments and during their storage under unsuitable conditions. Fats and oils are classified as so-called triacylglycerols, ie they are composed of glycerol and three fatty acids. It is the fatty acids bound to glycerol that determine the properties of fat and its stability. Eight types of fats and oils (sunflower oil, rapeseed oil, olive oil, coconut oil, linseed oil, butter, ghee and lard) were used for the analysis. The flaxseed oil sample was stored for 3 months in unfavorable storage conditions, ie in the light and in the heat. Other fats and oils were used for frying, baking, stewing, grilling and frying meat and onions. The aim of the work was to compare changes of fatty acids, changes of fat numbers and compare the amount of vitamin E contained in individual oils before and after culinary treatments. The results of the analysis showed that fat samples did not show significant changes in fat numbers, fatty acids or vitamin E after culinary treatments or improper storage. From this I conclude that fats and oils have been exposed to high temperatures and unsuitable conditions for a short time. The largest difference in the composition of fatty acids was measured for sunflower oil, where a higher amount of trans fatty acids was measured after treatment and overall a lower proportion of PUFA was measured than before treatment. As sunflower oil has a high content of polyunsaturated MK and a low smoke point, this result was expected. The highest concentration of vitamin E was found in rapeseed oil.
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Isolation and characterizaation of oil from some types of coffee
Vašků, Barbora ; Hoová, Julie (referee) ; Skoumalová, Petra (advisor)
Coffee, extract, oil, phenolic compounds, flavonoids, antioxidant capacity, SPF, critical wavelenght.
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Recovery of the method for assessment of fatty acids
Gross, Michal ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
The objective of this bachelor thesis is to verify recovery yield used for determination of fatty acids based on gas chromatography with flame-ionization detection. In the theoretical part, fatty acids and lipids are characterized and extraction of lipidic fraction from food samples with its subsequent adjustments is suggested. Furthermore, the principle and current instrumentation of capillary gas chromatography with flame-ionization detection and standard parameters for validation of the analytical method are specified. In the experimental part, verification of recovery yield of the method for assessment of fatty acids was performed. The used method includes extraction of lipids from a sample in accordance with the standard ISO 1735 regulation and transesterification of both free and bounded fatty acids catalysed by boron trifluoride according to the ISO 12966-2 standard regulation. The produced methyl esters can be effectively determined using gas chromatography with flame-ionization detector. Analysed samples of rapeseed oil and tilsiter-type cheese were purchased in a common food market.
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Comparison of efficiency of selected esterification methods
Jagoš, Slavomír ; Mahdalová, Martina (referee) ; Vítová, Eva (advisor)
The present thesis aims to determine the optimal method of analysis of fatty acids. The theoretical part offers a concise introduction to lipids, fatty acids and their analysis using gas chromatography with flame-ionization detection. The goal of the experimental part of this thesis was to test and compare three different types of esterification methods: basic esterification with methanolic solution of potassium hydroxide, acidic esterification with methanolic solution of hydrochloric acid and acidic esterification with boron trifluoride. By evaluating these methods from various aspects, including their yield, availability and safety of the used chemicals, and simplicity and speed of application, the suggested optimal method is the acidic esterification with boron trifluoride.
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