Ginseng is a popular tonic worldwide, and its effects can be enhanced by steaming. Previous studies regarding the steaming of ginseng mainly focus on the contained saponins but are rare on the volatile components. In the present study, we developed headspace sampling gas chromatography-mass spectrometry (HS-GC-MS)-based untargeted metabolomics to holistically characterize the altered volatile components of P. ginseng (PG), P. quinquefolius (PQ), and P. notoginseng (PN) during the process of steaming. Chromatographic separation conditions for GC-MS were optimized, by which the volatile components in both the raw and the steaming-processed products (at 1–10 h) for PG, PQ, and PN were characterized within 38 min on an HP-5MS elastic quartz capillary column. We could characterize 106 volatile components from PG, 106 from PQ, and 105 from PN. Multivariate statistical analysis could depict the transformation trajectory for PG, PQ, and PN induced by steaming at different times. Ultimately, 13, 16, and 14 significantly differential volatile components for the steaming of PG, PQ, and PN were discovered by GC-MS-based untargeted metabolomics analysis. Notably, 3-methyl-1-butanol, 2-pentylfuran, hexanal, caryophyllene, and (?)-aristolene were diagnostic to distinguish the raw and processed products for PG. α-Pinene, 2-pentylfuran, hexanoic acid, 2,3-butanediol, and pyruvic acid could distinguish the raw and processed PQ. Cyperene, furfural, 1-isopropyl-4,7-dimethyl-1,2,3,5,6,8a-hexahydronaphthalene, hydroxyacetone, and 1-pentanol could discriminate the raw and processed products of PN. The established GC-MS approach can be a practical tool to investigate the underlying processing mechanism of traditional Chinese medicine by revealing changes in its volatile components.
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