Recognition of characteristic aroma-active components in Qingke (highand barley) through flavoromics analysis

Qingke (highland barley) is a unique Tibetan Plateau crop, vital for local diets and traditional products. However, flavor differences among its varieties remain unclear. This work examined 4 representative Qingke varieties to investigate their flavor profiles and key aroma contributors. 60 aroma compounds were identified in the 4 Qingke varieties using gas chromatography-mass spectrometry and aroma extract dilution analysis. The results revealed that black/white and blue/yellow Qingke had similar flavor profiles respectively. Besides, black and white Qingke possessed more intense and abundant aromas, with 81 and 77 compounds, respectively. These two varieties were selected for further flavor analysis by aroma recombination experiment, which identified (E)-2-octenal, vanillin, γ-caprolactone, 3-methylthiopropanal and 4-vinylguaiacol as key odorants. Additionally, 1-pentanol, 3-hydroxy-2-butanone, phenylethanol and guaiacol were found to be the flavor differentiators of black and white Qingke using omission experiment. This work provides a scientific foundation for Qingke's flavor quality assessment, product development and future applications.