Multi-analytical approach for the characterization and geographical authentication of black pepper: Volatile analysis, antioxidant activity, and spectroscopic profiling

In this study, a selection of black peppercorns was analyzed to investigate their chemical and functional properties. The samples included peppercorns from the Kampot region in Cambodia (protected geographical indication, PGI; one of which is also certified organic), from Madagascar, and some commercially available products purchased from Italian supermarkets. For comparative purposes, a sample of green peppercorns was also included. Volatile compounds were analyzed by headspace solid-phase microextraction coupled with gas chromatography– mass spectrometry (HS-SPME-GC–MS) and explored using principal component analysis (PCA). The results highlighted clear differences in aroma profiles among the samples, with specific terpenoid compounds (such as sabinene, 3-carene, β-caryophyllene, and limonene) emerging as key contributors to sample differentiation. Antioxidant activity, evaluated through the DPPH radical scavenging assay, showed significant variability across varieties, with Madagascar pepper exhibiting the highest antioxidant capacity, indicating a higher content of bioactive constituents. Fourier transform infrared (FTIR) spectroscopy, applied as a rapid and nondestructive technique on individual peppercorns, coupled with partial least squares discriminant analysis (PLS-DA), enabled an effective classification of samples according to their geographical origin. The optimized FTIR–PLS-DA model achieved high classification accuracy in both cross-validation and external prediction, demonstrating its robustness for origin authentication. Overall, the results confirm that the integration of complementary analytical techniques provides a characterization of black peppercorns, allowing simultaneous evaluation of aromatic composition, functional quality, and geographical authenticity. This integrated workflow represents a practical and effective strategy for quality control and traceability of high-value spices.