| An integrated volatilomic strategy combining an electronic nose (E-nose) with gas chromatography-mass spectrometry (GC-MS) was applied to characterize the aroma profiles and assess the geographical differentiation of sun-dried green tea from Lancang County, Yunnan Province. Volatile constituents were systematically profiled in tea samples collected from ten production regions. Principal component analysis (PCA) of E-nose sensor responses revealed clear separation of the ZB sample from the main sample cluster, driven by markedly elevated signals in sensors W2W, W5S, and W3S, indicating that aromatic compounds, nitrogen-containing oxides, and long-chain alkanes are major contributors to its headspace profile. In contrast, XB and BW were positioned in close proximity in the PCA score plot, suggesting a high degree of similarity in their overall volatile fingerprints. Sensor loading analysis further indicated that W1W, W2S, W1S, and W2W contributed most strongly to sample discrimination, implying that methylated derivatives together with alcohols, aldehydes, and ketones constitute the principal odor-active chemical matrix of Lancang sun-dried green tea. Targeted GC-MS analysis identified 110 volatile compounds in total, predominantly alcohols, aldehydes, and ketones. Among these, linalool, phytol, and β-ionone were identified as key aroma-active constituents. Region-specific marker volatiles were also observed. The ZB sample exhibited enrichment of nerol and cyclohexenone, associated with an “orange blossom-green grassy” note. The XB sample was distinguished by the exclusive detection of cedrol and 1,2,3-trimethoxybenzene, which imparted a “grassy-woody, mildly sweet” base tone. The MJ sample, characterized by elevated phenylacetaldehyde, presented a composite “honeyed ripe-fruit with fresh citrus-woody” aroma. Hierarchical cluster analysis (HCA) further showed that DKH and BPDQ formed distinct clades. DKH was dominated by high-abundance linalool, corresponding to an intense “high-floral, citrus-like” aromatic profile, whereas BPDQ contained elevated levels of 1-octen-3-ol, associated with a “mushroom-like, damp-wood and mellow ripe-fruit sweetness” undertone. Overall, the combined use of E-nose pattern recognition and GC-MS compositional profiling enables chemotypic differentiation of volatile profiles and reliable geographical discrimination of sun-dried green tea from Lancang County. The identified volatile signatures provide objective physicochemical indicators for sensory quality assessment, origin authentication, and the protection of geographical indications. |
