Characterisation of the geographical origin of Italian potatoes, based on stable isotope and volatile compound analyses

Headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) and isotope ratio mass spectrometry (IRMS), in combination with appropriate statistical techniques, were used for the prediction of the geographical origin of Italian potatoes cultivated in three different Italian locations: Sicily, Apulia, and Tuscany. An analysis of variance, performed on log transformed headspace volatile compounds and isotopic ratios, highlighted statistically significant differences (p < 0.05) in the values of 15 volatile compounds and for all isotopic parameters among the potatoes produced in the three different geographical areas. A Post-Hoc test showed that only the oxygen and nitrogen isotopic ratios distinguished the potatoes produced at the three sites. Applying discriminant function analysis (DFA), the classification results were 100% by using both volatile and complete data set (isotopic ratios and volatile compounds), whereas classification results were 91.7% for isotopic data; the prediction ability of 91.7%, evaluated by leave-one-out procedure, was the same by applying DFA both on single data sets (volatile compounds or isotopic ratios) and on all data together.