Deciphering the bitterness contribution of Zanthoxylum bungeanum Maxim and its masking mechanism.

BACKGROUND: Zanthoxylum bungeanum Maxim. (Z. bungeanum) is widely applied in the processing of stewed beef with spices (SBS) to improve sensory quality, yet the processing-induced interactions between its flavonol glycosides and myofibrillar protein (MP) and their role in taste modulation remain poorly understood. In particular, the structural basis and binding behavior underlying protein-flavonol interactions during stewing, as well as their contribution to taste regulation. In this study, metabolomics combined with random forest modeling was employed to screen key taste-active compounds in SBS. The structure-affinity relationship and the mechanism underlying the interaction between flavonol glycosides and MP were investigated using fluorescence spectroscopy, Fourier transform infrared spectroscopy, and molecular docking. RESULTS: The top 15 key taste compounds were identified by a random forest model as significant contributors to flavor enhancement. A subsequent investigation focused on isoquercetin and astragalin due to their notably high variable importance scores and acknowledged chemical relevance. E-tongue results suggest that MP exhibits strong bitterness-masking activity. The interaction of flavonol glycosides (isoquercetin and astragalin) with MP in higher pH environments caused fluorescence quenching. Molecular docking results indicate that variations in the molecular geometries of isoquercetin and astragalin contribute to their distinct binding interactions with bitter taste receptor TAS2R14. CONCLUSIONS: These findings provide mechanistic insight into processing-induced protein-flavonol interactions and offer theoretical guidance for optimizing spice-assisted meat processing strategies and taste quality regulation. © 2026 Society of Chemical Industry.