Effects of conventional and microwave heating on the degradation of olive oil

A comparative study was performed to evaluate the effects that microwave (12 and 15 min at 1,100 W) and conventional heating (36 and 45 min at 230 °C) have on olive oil (refined+virgin). The extent of the oxidative and hydrolytic degradation of the differently heated oils was evaluated by high performance sizeexclusion chromatographic analysis of their polar compounds. The experimental results showed a great degradation of the oils with values of polar compounds higher than 26% at the most intense treatment. Significantly higher amounts of polar compounds, of triglyceride oligopolymers – known to have adverse effects on human health – and of oxidised triglycerides were found in microwaved than in conventionally heated oils, indicating a higher extent of oxidative degradation