Multifaceted Regulation of Tea Astringency: A Review of Intervention Pathways by Co-Existing Flavor Components

Tea, as a widely consumed natural beverage, has long been a focus of sensory quality research due to its harmonious and layered flavor. Among the complex flavor characteristics of tea, astringency is one of the key attributes determining the overall tea flavor, and its generation is closely related to the interaction between polyphenolic compounds and salivary proteins. Phenolic hydroxyl groups and benzene rings in the molecular structure of polyphenols can bind to salivary proteins via non-covalent interactions to form insoluble complexes, which can alter oral lubrication and elicit astringency. However, the tea astringency is not only determined by polyphenols in tea but also modulated by flavonol glycosides, alkaloids, amino acids, polysaccharides, and other flavor components. Depending on differences in functional group composition and spatial structure, these flavor components act on different stages in the formation of astringency, and ultimately affect the astringency expression. These regulatory pathways can be categorized into three types based on their stages and targets: protein-side regulation, polyphenol-side regulation, and complex aggregation process regulation. This review systematically summarizes the molecular mechanisms, representative components, and regulatory effects of these three categories, aiming to provide theoretical support for the targeted modulation of tea flavor quality and offer insights for research on other astringent foods.