Biosensors for monitoring the isothermal breakdown kinetics of peanut oil heated at 180 °C. Comparison with results obtained for extra virgin olive oil

The present research was devoted to studying the kinetics of the artificial rancidification of peanut oil (PO) when a sample of this oil was isothermally heated at 180 °C in an air stream. The formation of radical species due to heating was evaluated using a radical index whose value was determined using a biosensor method based on a superoxide dismutase (SOD), while the increasing toxicity was monitored using a suitable toxicity measuring probe based on the Clark electrode and immobilized yeast cells.An extra virgin olive oil was isothermally rancidified under the same experimental conditions and the corresponding data were used for the purpose of comparison.Both the so-called “model-fitting” and the classical kinetic methods were applied to the isothermal process biosensor data in order to obtain the kinetic constant rate value at 180 °C.

• We determined the time required to reach the maximum toxicity level at 180 °C, at which oil is cooked and fried. • The two biosensors for free radicals and total toxicity indexes resulted useful to test the oil rancidification process. • Model-fitting method is found to be a useful tool to study the kinetics of the oil rancidification process.