The objective of this study, was to examine the alterations of the fatty acids profile and the formation of trans fatty acids isomers during heating of soy oil (SO) and partially hydrogenated soy fat (PHSF) in the process of french frying. The fatty acids profile was examined by gas chromatography with a 100m capillary column. The fatty acids trans monounsaturated were the predominant among trans isomers. The isomers trans monounsaturated corresponded to 2.1% of the total, after 10 hours of frying, and 14.3% after 50h - frying. Poliunsaturated fatty acids decreased from 59.9% to 32.6% after 50h - frying. For the PHSF, the initial content of 20.2% of trans monounsaturated isomers increased to 28% after 50h - frying, and omega3 and omega6 - essential fatty acids decreased from 12.8 to 7.3%, in the same period. These results confirmed the formation of trans isomers in oil and hydrogenated oil in frying process, and that the trans isomers formation occurred in lower proportion in the hydrogenated oil. These results show the importance of identifying the trans fatty acids in oils and fats utilized in frying process.
lipids; frying; fatty acids; trans isomers
