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Accelerated oxidation: Comparative study of a new reactor with oxidation stability instrument

Comandini, Patrizia, Verardo, Vito, Maiocchi, Paola, Caboni, Maria Fiorenza
European journal of lipid science and technology 2009 v.111 no.9 pp. 933-940
Helianthus annuus, activation energy, air, correlation, extra-virgin olive oil, foods, lipid peroxidation, new methods, oxidation, oxidative stability, oxygen, palm oils, sunflower oil, temperature, vegetable oil
Accelerated oxidation tests, such as the determination of the induction period, increase the lipid oxidation rate by exposing a food to elevated temperatures, in the presence of excess quantities of air or oxygen. In addition to the well-founded oxidative stability index (OSI) method, an innovative and promising technique is the oxidation test (OXITEST) reactor. A new analytical method was developed with OXITEST to oxidize vegetable oils. At a preliminary stage of the investigation, the induction periods of sunflower and extra-virgin olive oil obtained by the OXITEST reactor were plotted against temperature, on the basis of the Arrhenius law; the activation energy and the frequency factor of lipid oxidation were calculated and resulted in 98.61 kJ/mol and 2.33x10¹⁰ s⁻¹, respectively, for sunflower oil and 106.48 kJ/mol and 6.27x10¹⁰ s⁻¹, respectively for extra-virgin olive oil. The new oxidative technique was employed to determine the induction periods of vegetable oils; the results obtained were well correlated with those achieved with OSI technology, with a Pearson correlation coefficient r = 0.9785 (p <0.05) for oilseeds and palm oil and r = 0.9501 (p <0.05) for extra-virgin olive oils.