Lipid quality of fried and scrambled eggs prepared in different frying medium

Abstract

The heating of oils and fats at high temperatures can lead to an oxidation process that involves a series of complex reactions producing a great diversity of oxidation products, including peroxides and free fatty acids. One of the foods normally prepared by quick frying using oils and fats is chicken eggs. This study aimed to evaluate the percentage of oil and fat absorption, peroxide index, degree of acidity, p-anisidine value, and TOTOX as well as the lipid profile of chicken eggs prepared whole or mixed with extra virgin olive oil, coconut oil, lard, butter, soy and canola oil and without the use of oils or fats. The eggs were prepared in a nonstick pan with 1:10 (w/w) oils or fats. The lipid fraction was cold extracted with hexane and purified for analysis. There was considerable absorption of oils and fats by the eggs. The absorption for whole eggs ranged from 64.0 to 73.0%. The absorption in the scrambled eggs was significantly higher than that in whole eggs, ranging from 78.1 to 88.2%. The water loss during the preparation was higher for scrambled eggs (12.5%) than whole eggs (11.1%). The values of anisidine, acidity, peroxide and TOTOX were highly varied and not notable, showing that rapidly frying eggs under experimental conditions and using the oils or fats studied was unable to cause significant degradation and oxidation of the lipids tothe point of harming the final quality of the egg. The average free fatty acid value was 1.2 mg KOH/g for fried eggs and 1.5 mg KOH/g for scrambled eggs. The average peroxide value was 10 meq/kg for whole or scrambled eggs, while average p-anisidine value was 5.7 for whole eggs and 4.6 for scrambled eggs. The same phenomenon was observed for the lipid profile, analyzed by gas chromatography since no significant changes were observed in relation to the content of saturated and unsaturated fatty acids when eggs were made whole or scrambled, and the composition of the eggs at the end of preparation was correlated to the composition of the oil or fat used for the preparation due to considerable absorption. In conclusion, the choice of oil or fat used for frying eggs should be based on an individual's energy needs, provide healthier food and cooking methods.