PTR-MS-TOF analysis for the characterization of saffron from different geographycal origins.

Saffron is an expensive spice obtained from the dried stigmas of the flower of Crocus sativus L. primarily used in cooking, although it is well known for its medicinal purposes, it is also utilized for its color in dyes and paints and for its scent in perfumes. Iran is one of the most important producers, distributing low price saffron all over the world. Saffron quality is determined by colour, taste, and aroma, which depend on many factors such as soil, climate, rainfall, harvest time, and finally postharvest treatments. In the present study, the aromatic profiles of saffron from three Iranian regions were compared with samples produced in three Italian regions (samples were provided by Associazione Zafferano Italiano). The characterization was performed with a PTR-MS-TOF analyzer, a non-invasive approach that allows the achievement of whole mass spectra of volatiles with high resolution power, leading to a better interpretation of mass spectra. About 30 molecules have been detected, most of which already published. Only five fragments have been found, confirming the low fragmentation characteristic of the PTR-MS-TOF analysis. Furthermore, mass identified as 4-hydroxy-2,6,6-trimethyl-1-cyclohexen-1- carboxaldehyde (HTCC), the aglycone precursor of safranal, was not present in all the samples, indicating quality in the transformation process. All volatiles detected have been subjected to classification analysis (principal component analysis, PCA and discriminant analysis, DA) in order to extract relevant information from complex data sets, and hierarchical cluster analysis (HCA) was also used to show similarity between samples. Samples from Iran, grouped accordingly to their geographic origin, appeared to have many common volatiles. Samples from Italy, despite grouping separately from those from Iran, formed three distinct groups. These results show the potentiality of PTR-MS-TOF analysis as a helpful tool to discriminate saffron samples with different geographical origins.