Multiscale Elucidation of Taste Interactions in <i>Osmanthus</i> Green Tea: Bitter Masking via EGCG and Phenylethanoid Glycoside Interplay

This study revealed the molecular mechanism by which <i>Osmanthus fragrans</i> masks the bitterness of summer-autumn green tea infusion. Taste dilution analysis identified catechins such as EGCG in green tea as the primary bitter compounds. Phenylethanoid glycosides (PhGs), such as verbascoside and salidroside in <i>Osmanthus fragrans</i> exhibited significant bitter-masking effects. Molecular docking identified TAS2R31 as the primary bitter receptor for EGCG, with verbascoside or salidroside competitively disrupting the EGCG-TAS2R31 binding. Molecular dynamics simulations showed that PhGs altered the TAS2R31 conformation, reducing its α-helix content, increasing structural flexibility, and decreasing hydrogen bonding with EGCG. This conformational change correlated with a decrease in the binding affinity of TAS2R31 for EGCG. Spectroscopic analysis further demonstrated that PhGs efficiently quenched the intrinsic fluorescence of TAS2R31. Thus, the <i>Osmanthus</i>-derived PhGs were a key substance that reduces the bitterness of OSGT, which could affect the binding between EGCG and bitterness receptors by altering the conformation of bitterness receptors.