Study on the migration regularity of volatile flavor compounds during the roasting process of Tartary buckwheat tea based on HS-GC-IMS and chemometrics.

Roasting is a critical processing step that strongly influences the chemical composition, volatile profile, and overall quality of Tartary buckwheat tea. This study investigated the dynamic changes in volatile flavor compounds during roasting using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with chemometric analysis. Roasting significantly increased the contents of total flavonoids (2.29 g/100 g) and protein (15.67 g/100 g), while reducing the moisture content (5.77 g/100 g), particularly at stages X4-X6 (15-25 min). A total of 79 volatile compounds were identified by HS-GC-IMS, among which alcohols and ketones were predominant. Stages X3-X5 (10-20 min) were identified as the critical period for flavor accumulation. Partial least squares discriminant analysis (PLS-DA) identified 13 key discriminant compounds, including propyl acetate, hexyl butyrate, isoamyl formate, sec-butyl acetate, propanal, acrolein, 3-methyl-2-butenal, (E)-2-heptenal, methyl heptenone, 3-methyl-2-pentanone, 2-hexanone, sec-butanol, and 1-octene, as potential flavor markers. These findings clarify the roasting-dependent flavor evolution of Tartary buckwheat tea and provide a theoretical basis for process optimization to improve aroma quality.