Optimization using chemometrics of HS-SPME/GC-MS profiling of saffron aroma and identification of geographical volatile markers

Gas cromatography with mass spectrometry detection coupled to headspace solid-phase microextraction (SPME) was used to analyse the aroma profile of saffron (Crocus sativus L.). The influence of the saffron amount and form (intact stigmas vs. powder) on the intensity of the chromatograms was preliminarily evaluated. Moreover, the mutual effects of the sample temperature and exposition time of a polydimethylsiloxane SPME fiber was investigated by response surface methodology. Saffron samples produced in L'Aquila (Italy), Iran and Morocco, and commercial spices were analysed under application of the optimised SPME conditions and geographical classification was attempted by linear discriminant analysis applied to the relative peak areas of all the detected volatiles. The spices produced in the different geographical areas and the commercial products were discriminated with good accuracy, 91% of external samples being correctly classified using leave-one-out cross-validation. An acceptable differentiation (73% of correct predictions) was obtained by considering only the major aroma components.