Monitoring the nutritional profile of edible fats and oils after culinary treatments

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