GC‑IMS combined with chemometrics for discriminating volatile markers in differently processed licorice (Glycyrrhiza spp.).

Licorice (Glycyrrhiza spp.) has received extensive attention due to its remarkable medicinal value and dual medicinal and edible properties. In this study, gas chromatography-ion mobility spectrometry (GC-IMS) was employed to investigate volatile organic compounds (VOCs) in three typical processed licorice products, including stir-fried licorice (SFL), honey-fried licorice (HRL), and wine-fried licorice (WPL). A total of 143 signal peaks were detected, from which 112 compounds were successfully identified, predominantly belonging to aldehydes, alcohols, and ketones. Fingerprint analysis revealed that the three processed samples shared the same types of VOCs but differed in their contents. Principal component analysis (PCA) further confirmed a clear separation among the three processing treatments. The composition and content of VOCs act as crucial factors determining the flavor characteristics and sensory quality of processed licorice. Euclidean distance analysis and partial least squares discriminant analysis (PLS-DA) were performed to clarify the correlation characteristics of VOCs among differently processed licorice samples. The results identified that multiple flavor‑related differential volatile markers were closely associated with different processing methods. Unlike conventional GC‑MS, GC‑IMS requires no derivatization or complex sample preparation, enables separation of isomer and monomer/dimer signals, and provides high‑throughput volatile profiling - making it particularly suitable for differentiating processed herbal products. GC-IMS facilitates rapid and intuitive visualization of dynamic changes in volatile components during licorice processing, providing a new analytical tool and theoretical basis for process optimization, quality evaluation, and mechanism research on licorice processing.