HS-SPME-GC/MS-Based Volatile Profiling and Chemometric Discrimination of Selected Herbal Teas

Herbal teas prepared from aromatic plants possess complex volatile profiles associated with their characteristic sensory properties. In this study, the headspace volatile profiles of aqueous infusions prepared from Teucrium polium, Mentha pulegium, Rosmarinus officinalis, Lavandula stoechas, and Ocimum basilicum were investigated using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC/MS). Three independent infusions were prepared for each species, resulting in 15 individual volatile profiles, which were evaluated by principal component analysis (PCA) and hierarchical cluster analysis (HCA). A total of 115 volatile compounds were tentatively identified across the five species. Monoterpenoids were the predominant chemical group in M. pulegium (70.17 ± 0.20%), R. officinalis (81.80 ± 0.04%), L. stoechas (96.95 ± 0.08%), and O. basilicum (77.60 ± 0.35%), whereas T. polium showed a more heterogeneous profile comprising substantial proportions of monoterpenoids (49.95 ± 0.16%) and sesquiterpene hydrocarbons (31.32 ± 0.24%). The principal volatile constituents were carvacrol and germacrene D in T. polium; pulegone, piperitone oxide, limonene, and 1,8-cineole in M. pulegium; 1,8-cineole, borneol, and camphor in R. officinalis; fenchone and camphor in L. stoechas; and linalool, eugenol, and methyl chavicol in O. basilicum. The first two principal components accounted for 66.44% of the total variance. The three independently prepared infusions of each species formed compact groups in the PCA score plot, with T. polium showing the most distinct separation. PCA associated M. pulegium particularly with pulegone-, piperitone oxide-, and piperitenone oxide-related variation, whereas HCA grouped the three preparations of each species together and indicated the closest species-level similarity between R. officinalis and L. stoechas. Overall, HS-SPME-GC/MS combined with PCA and HCA provided a useful exploratory approach for the comparative characterization and species-related differentiation of herbal tea headspace volatile profiles under standardized infusion conditions.