The New Aristocrat of Wuyi Rock Tea: Chemical Basis of the Unique Aroma Quality of "Laocong Shuixian".

Laocong Shuixian (LCSX), a premium Wuyi rock tea derived from aged Shuixian tea trees, is valued by consumers for its distinctive "Cong flavor"-a unique aroma profile characterized by woody, bamboo leaf, and glutinous rice notes. However, the chemical basis and underlying mechanisms of this unique aroma remain unclear. Here, we assessed and established a professional sensory evaluation panel using the PanelCheck software, with significant F-value levels >5% confirming the panel's discriminative capacity for key "Cong flavor" attributes. Combining a literature review and sensory analysis, we identified the descriptive terms associated with the "Cong flavor" of LCSX. Gas chromatography-olfactometry-mass spectrometry (GC-O-MS) analysis revealed 36 key aroma-active compounds, among which theaspirone (OAV = 500.05, ACI = 37%, R(woody) = 0.82), δ-decalactone (OAV = 65.6, ACI = 4.3%, R(woody) = 0.77), and 2-acetylpyrrole (OAV = 163, ACI = 9%, R(rice) = 0.74) were identified as the contributors to the woody and rice-like notes of LCSX based on odor activity values and correlation analyses. Molecular docking results demonstrated that these compounds spontaneously bind to multiple olfactory receptors, with binding affinity ≤-5.0 kcal/mol, providing insights into their roles in human aroma perception: theaspirone to OR8D1; δ-decalactone to OR1E2, OR5M3, OR7D4, OR7G1, OR8D1 and OR8G1; and 2-acetylpyrrole to OR1E2, OR1G1, OR5M3, OR7D4, OR7G1, OR8D1, and OR8G1. This study enhances our understanding of the formation of distinctive aroma qualities in oolong tea and establishes a foundation for further research into its sensory and chemical properties.