Mechanisms of astringency modulation: How sugars and organic acids modulate epigallocatechin gallate astringency in...

New-style fruit tea is widely consumed for its balanced sweet-sour taste and refreshing mouthfeel. However, (-)-epigallocatechin gallate (EGCG) is a key contributor to astringency in these beverages. This study investigated the effects of organic acids and sugars on EGCG-induced astringency and explored the underlying molecular mechanisms. Sensory evaluation was conducted to quantify astringency intensity in EGCG solutions containing different concentrations of sugars and organic acids. Organic acids significantly enhanced astringency in a pH-dependent manner, whereas sugars reduced perceived astringency. Rheological measurements and oral tribology analysis were performed to characterize lubrication changes. Sugars increased the particle size and improved the lubricity of EGCG-mucin complexes, resulting in lower friction coefficients. Molecular docking analysis further demonstrated that sugars strengthened EGCG-mucin binding through additional hydrogen bonds and hydrophobic interactions. These results provide mechanistic evidence that sugars and organic acids differentially regulate EGCG-induced astringency by altering intermolecular interactions and oral lubrication behavior. The findings contribute to a better understanding of taste modulation in complex fruit tea systems and may support formulation strategies for improving sensory quality.