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.

Automated summary

The study analyzed 68 samples of red garlic from four Italian areas to investigate if volatile composition is related to geographical origin, using HS-SPME/GC-MS analysis. The PLS-DA model successfully classified most external samples, and VIP analysis identified 13 organosulfur compounds significantly dependent on the garlic flavor and the origin of the bulbs.