DSC evaluation of extra virgin olive oil stability under accelerated oxidative test: Effect of fatty acid composition and phenol contents (original) (raw)

Evoo bottles stored at room temperature, which can develop high levels of oxidation leading to undesirable flavour. Thus, new, simple and fast methods are needed for the evaluation of oxidative status of Evoo, avoiding expensive and time consuming techniques and assuring correct classification among legally defined commercial categories 4. Differential scanning calorimetry DSC is a well known thermoanalytical technique that is used in several applications in the field of vegetable oils 5, 6. In recent years, several publications have emerged on the use of DSC for the assessment of Evoo quality 7 9. These have studied the cooling and heating thermal properties and established the composition of Evoo in terms of triacylglycerols, fatty acids and minor components 10, 11 , also using statistical approaches 12, 13. DSC was also found to be a valuable tool for assessing the oxidative deterioration of vegetable oils 14. Its application to evaluate the degree of thermo-oxidation after conventional heating has been reported for Evoo 15 as well as Abstract: Three extra virgin olive oils having different fatty acid compositions and total phenol contents were submitted to an accelerated storage test at 60 for up to 21 weeks. Their oxidative status, evaluated by peroxide values and total phenolic content, was related to differential scanning calorimetry cooling profi les and thermal properties. Changes in crystallization profi les were consistent starting from 12 weeks for the two oil samples (B and C) that had a higher content of linoleic acid and medium/low amounts of phenols, respectively, whereas they became detectable at the end of the test for the remaining oil (sample A). Decrease of crystallization enthalpy and shift of transition towards lower temperature were also evident at 4 weeks of storage for samples B and C, whereas the same changes in the transition profi le were noticeable at 12 weeks for sample A. Differential scanning calorimetry appears to be suitable for the discrimination of oxidative status of extra virgin olive oils with widely different fatty acid composition.