Evaluation of flavor characteristics in tartary buckwheat (Fagopyrum tataricum) by E-nose, GC-IMS, and HS-SPME-GC-MS: Influence of different roasting temperatures

In this study, the changes in flavor characteristics of tartary buckwheat (TB) roasting at temperatures of 160 °C, 180 °C, 200 °C, and 220 °C for 8 min were evaluated by chromatography-ion mobility spectrometry (GC-IMS), headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), electronic nose (E-nose), and electronic tongue (E-tongue). 52 volatile compounds were identified by GC-IMS, including 9 esters, 21 aldehydes, 6 ketones, 1 lactone, 7 alcohols, 1 acid, 4 furans, 1 pyrazine, and 2 monoterpenes. 36 compounds were quantified by HS-SPME-GC-MS, and 8 volatiles with odor activity values (OAV) > 1 contributed to the overall TB aroma. Notably, 2-ethyl-3-methylpyrazine and 3,5-diethyl-2-methylpyrazine were identified as the aroma-active compounds in the 180 °C, 200 °C, and 220 °C roasting groups. Additionally, principal component analysis (PCA) based on the signal intensity of the detected flavor compounds revealed the TB samples from NC and the four roasting groups could be distinguished effectively. Our results indicated that roasting substantially enhanced the overall aroma intensity of TB. Overall, 180 °C of roasting was beneficial from the flavor point of view for the obtained TB. In conclusion, our findings suggest that roasting at 180 °C is the most favorable option from a flavor perspective for achieving high-quality TB.