Exploring the key effects of non-volatile acid compounds on the expression of dominant flavor in lager beer using flavor matrix and molecular docking

The trace compounds in lager beer were extraordinarily diverse, yet the composition of key flavor compounds and the mechanisms underlying their quality expression remain unclear. This gap significantly hindered the development of advanced quality control technologies for lager beer. In this study, 39 non-volatile acids were quantified across different lager beer brands using RP-HPLC. SQDA and electronic tongue analysis revealed similar overall taste characteristics among the four beers, characterized by prominent umami and sweetness, along with noticeable bitterness and sourness. As a result, supported by TAV analysis, PLS-DA, RF model, and flavor matrices, L-lactic acid, citric acid, succinic acid, and L-arginine were identified as key differential markers for the expression of distinctive taste attributes in different lager beers. Further, molecular docking demonstrated that L-lactic acid, succinic acid, and citric acid could bind to the sweetness receptor T1R2/T1R3, with their sweetness intensities increasing sequentially. Additionally, L-arginine exhibited umami perception capability for binding to the umami receptor T1R1/T1R3. • Four lager beers showed prominent umami and sweetness; •L-lactic acid, citric acid, and succinic acid were the molecular basis of sweetness; •L-arginine served as the molecular foundation for umami perception; •Molecular docking was conducted to investigate their taste perception mechanisms; •The physical properties of organic acids affect their sweetness expression.