Behavior of the Chemical Composition of the Refined, Blended, and Extra Virgin Olive Oils During the Heating Process

The present study was carried out to evaluate the differences in the radical scavenging activity (RSA) of the total, lipidic, and polar fractions of the refined oils (Sunflower, corn, and soya oils), extra virgin olive oils (EVOOs), and blended oils, during 10 h of heating treatment (180°C). The RSA was determined by measuring the disappearance of 2,2-diphenyl-2-picrylhydrazyl radical [DPPH•] at 515 nm. Oxidative stability and polar phenols were also studied. The unheated EVOOs showed the highest level of phenol compounds and as a consequence the highest oxidative stability and RSA of total and polar fractions. Refined samples showed a high RSA of lipidic fraction. After heating at 180°C, all the studied parameters showed a reduction due to the degradation of the antioxidant components. During heating at frying temperature, the type of oil is a determinant factor.