Comparative Analysis of Volatile Profiles from Rosa gallica L. Flowers Using HS and SPME Extraction Coupled with GC-MS

Volatile composition is a core trait that determines the ornamental and application value of Rosa flowers. In the current study, the volatile profiles of freeze-dried Rosa gallica flowers were comprehensively characterized via gas chromatography-mass spectrometry (GC-MS), coupled with heatmap clustering, principal component analysis (PCA), and relative odor activity value (rOAV) determination. A total of 181 volatile compounds were identified, and distinct volatile profiles were observed between flower samples treated with headspace extraction (RG-HS) and solid-phase microextraction (RG-SPME). Alcohols were the dominant volatile class in RG-SPME, whereas aldehydes were abundant in the RG-HS group. In terms of aroma characteristics, RG-SPME presented stronger green, floral, citrus, and fatty odors, while RG-HS exhibited a more pronounced fruity note. Moreover, sulfurous and dairy notes were unique to RG-SPME and RG-HS, respectively. Additionally, 27 volatiles showed rOAV above one, with 2,3-butanedione and trans-citral having the greatest rOAV value of 100, were identified as the potential aroma-active contributors to butter-like and citrus odors in RG-HS and RG-SPME, respectively. These results provide a methodological reference for volatile profiling of R. gallica flowers, and support the selection of appropriate extraction methods for future research and resource utilization.