Effects of different drying methods on key aroma compounds and glucosinolate precursors in Cardamine violifolia

Drying is essential for preserving Cardamine violifolia , a selenium-rich Brassicaceae vegetable, and for producing powders for functional foods. However, the effects of different drying methods on its aroma and flavor precursors remain unclear. This study compared the volatile and glucosinolate profiles of C. violifolia subjected to freeze-vacuum drying (FVD), microwave-vacuum drying (MVD), hot-air drying (HAD), and sun drying (SD). HS-SPME-GC–O–MS identified 58 volatile compounds, including 22 aroma-active compounds. Eleven of these were confirmed as key aroma compounds based on odor activity values and aroma recombination/omission experiments. Benzyl isothiocyanate contributed predominantly to the characteristic pungency. Other key odorants included trans-2-hexenal, benzaldehyde, benzeneacetaldehyde, nonanal, β-cyclocitral, 1-octen-3-ol, ketoisophorone, and β-ionone, which contributed to green, sweet, and mushroom-like notes. FVD best preserved the pungent–green flavor of fresh samples, owing to low-temperature dehydration retaining the highest levels of benzyl isothiocyanate and aldehydes. MVD partially retained pungency and generated 3-ethyl-2,5-dimethylpyrazine, which is responsible for roasted nuances. HAD and SD substantially reduced the pungent aromas and enhanced sweet and musty notes. This shift is likely due to extended heat exposure and oxidation, which produced higher concentrations of nonanal, β-cyclocitral, 1-octen-3-ol, 3,5-octadien-2-one, ketoisophorone, β-ionone, and dihydroactinidiolide. Glucosinolate analysis revealed glucotropaeolin (benzyl glucosinolate) as the predominant component, consistent with its major degradation products (benzyl isothiocyanate and benzyl nitrile) in headspace. HAD retained the highest total glucosinolate content due to rapid moisture removal and the stability of glucosinolates at the applied drying temperature. These findings provide useful references for the flavor quality of Brassicaceae vegetables after drying. • Benzyl isothiocyanate is the major pungent odorant with high OAVs. • Freeze-vacuum drying best preserved the pungent aroma of Cardamine violifolia. • Heating reduced isothiocyanates but promoted nitriles, alcohols, ketones. • Glucotropaeolin is the dominant glucosinolate and the key aroma precursor. • Hot air drying retained the highest total glucosinolate content.