Effect of heating on fatty acid composition of edible oils and fat

Bc. Filip Vojáček

Diplomová práce

Abstract:

Frying of food is one of the oldest methods of cooking. Oil is during the frying process subjected to aggressive conditions such as high temperature, and the presence of oxygen and water. These conditions cause thermal-oxidative degradation changes in the oil according to thermal-oxidative stability of the oil. These changes influence a fatty acid composition of the oil. In this study has been examined the influence of constant heating of oil on its fatty acid composition. Seven types of oil and one type of fat were heated up at 190 °C in a commercial fryer. The heating process steadily continued for 24 hours and after every 4th hour samples were collected. From the samples, the fatty acid methyl esters were prepared by transesterification according to the method of E.W. Hammon (2003). Was performed the GC-MS analysis in order to determine the fatty acid composition according to detected fatty acid methyl esters. There the relative representation of individual fatty acids was monitored. Was found significant decreasing in the representation of unsaturated fatty acids due to the decomposition of double bonds. This decomposition occurs significantly after the eighth hour of heating. The most influenced was the representation of linoleic acid and oleic acid. Their content in all tested samples was decreased after the heating period. The most significant increase occurred in stearic acid content. Was also found that during the heating process the oils and fat becoming be more saturated.

Keywords

transesterification, GC-MS, fatty acids, edible oil

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 26. 4. 2019

Obhajoba závěrečné práce

• Vedoucí: Ing. Klára Urbanová, Ph.D.

Česká zemědělská univerzita v Praze

Fakulta tropického zemědělství

Magisterský studijní program / obor:
Tropické zemědělství / Sustainable Rural Development in the Tropics and Subtropics