Vegetable species significantly affects the phenolic composition and oxidative stability of extra virgin olive oil used for roasting

The purpose of this study was to evaluate the compositional changes (quality parameters, fatty acids, phenolic compounds, and antioxidant capacity) in extra virgin olive oil (EVOO) after cooking treatment in realistic domestic conditions (roasting at 180 degrees C/60 min) with the addition of typical Mediterranean vegetables (potato, carrot, onion, and mix of those vegetables in equal proportions). Heating increased oil oxidation parameters, while the addition of vegetables during roasting reduced the degree of oil secondary oxidation. EVOO fatty acids have shown strong resistance to heating regardless of the vegetable species added. The initial phenolic composition and radical-scavenging activity of EVOO were significantly altered after roasting resulting in a particular response, depending on the vegetable species used in the treatment. In the presence of vegetables, olive oil total identified phenolic content suffered a major loss, with only 28.27%, 22.00%, 19.87%, and 19.03% of the initial content being preserved after roasting with carrots, potato, onion, and mixed vegetables, respectively. A considerable correlation of both moisture content and pH of the vegetables and the evaluated parameters was found. Obtained results might contribute to understanding the fate and preservation of EVOO beneficial composition in the course of the real cooking conditions.