In this work, a multidisciplinary approach for the evaluation of extra virgin olive oil traceability (geographical provenience and botanical differentiation) is presented. Conventional techniques such as major chemical component determination (triacylglycerols, TAG and fatty acids) and other novel approaches as stable isotopic ratio (13C/12C in combination with 18O/16O) and thermal properties obtained from cooling curves and their deconvoluted peaks by means of differential scanning calorimetry were compared. Fifty-three samples from different Italian regions, diverse cultivars, and two Mediterranean areas (Italy and Croatia) were analyzed with all the three techniques. The oils exhibited different values especially for δ18O and thermal properties of the deconvoluted peaks of crystallization according to Italian regions and/or cultivars. Data were treated by means of linear discriminant analysis inserting all parameters as predictors in models where the potentiality to discriminate oils was tested. All models revealed a good resolution among categories with selected TAG, δ18O values, and thermal properties of the deconvoluted peak set at the highest temperature exhibiting the highest weight for the discriminant functions. These findings could give strength to the utilization of new analytical techniques supporting those traditionally employed, also sustained by proper chemometric procedures, as suitable for the resolution of extra virgin olive traceability.
Practical applications: Consumers' awareness of extra virgin olive oil traceability has recently increased the interest for new methods that can assess its geographical and botanical origins and new findings in this sector represent a key factor affecting the purchases in non-producer countries. Multidisciplinary approaches supported by chemometric procedures enable the building of large databases and classification models for the determination of the provenience of extra virgin olive oil.