On testing quality and traceability of virgin olive oil by calorimetry.

Extra Virgin olive oils (7 samples) originating from different areas of Tuscany, defective olive oils (5 samples), commercial edible seed oils (4 samples) and two commercial samples of olive oil (one declared 'extra virgin olive oil' and one olive oil') were studied by different calorimetric techniques: high sensitivity isothermal, differential scanning, and modulated scanning calorimetry. The temperature interval (-60)-(+30)degrees C was explored for monitoring: i) the main features of the liquid <-> solid phase transitions, ii) the nucleation and growth rate of the polymorphous crystalline phases of the triacylglicerols, and iii) the melting process. This investigation was planned for verifying the utility and effectiveness of calorimetry for screening quality and origin of olive oil. To this end, the main calorimetric operation modes have been applied, the experimental results reported and their utility for developing an effective and reliable screening protocol discussed.