Organosulfur volatile profiles in Italian red garlic (Allium Sativum L.) varieties investigated by HS-SPME/GC-MS and chemometrics

Sixty-eight samples of red garlic harvested in four Italian areas were analyzed by means of head-space solid phase micro-extraction (HS-SPME) coupled to gas-chromatography with mass spectrometry (GC-MS) to test whether the volatile composition is related with the geographical origin of the bulbs. HS-SPME/GC-MS analysis was optimized by means of a Box-Behnken design of experiment. Once GC-MS signals were collected and the volatiles identified, geographical classification was attempted by Partial Least Squares Discriminant Analysis (PLS-DA). To perform the external validation of the model, the investigated samples were divided into a training and a test set of 42 and 26 samples, respectively. The PLS-DA model correctly classified 21 external samples. Eventually, Variable Importance in Projection (VIP) analysis identified 13 organosulfur compounds (two sulphides, eight disulphides and three trisulphides), among the 25 detected ones, displaying a content in garlic flavour significantly dependent on the geographical origin of the bulbs.