Decoding Qingke's aroma compounds: Flavor contributions, interactions and barley contrast

Qingke (Highland barley), an indispensable crop on China's Qinghai-Tibetan Plateau, was investigated for its characteristic aroma through flavoromics. A comparative analysis with barley identified 16 key aroma compounds in Qingke and 9 in barley using gas chromatography-olfactometry-mass spectrometry (GC-O-MS), aroma extract dilution analysis (AEDA), odor activity values (OAVs) and recombination and omission experiments. Therefore, 6 shared components accounted for the similarities of their aromas, including 2,3-butanedione (creamy), 2-pyrrolidinone (wheaty), γ -nonanolactone (milky), γ -valerolactone (milky), vanillin (sweet) and hexanal (grassy), and vanillin was served as a key differential marker. The 10 unique Qingke components included ( E, E )-2,4-decadienal, methional, benzeneacetaldehyde, 4-hydroxy-benzaldehyde and others. Additionally, further perceptual interaction research through the Feller additive model revealed an additive effect between vanillin and γ -nonanolactone, whereas 2-pyrrolidinone, 2-acetylthiazole, 4-vinylguaiacol and hexanal exhibited masking effects on vanillin and γ -nonanolactone, respectively. These results can provide a theoretical basis for the flavor quality control of Qingke and its products.