Self-assembled particles in tea infusions: Chemical-structural interplay enables enhanced flavor

Infusion systems contain three distinct phases. While the flavor contributions of the true solution phase are well characterized, the roles of the colloidal and suspended phases remain largely underexplored. Here, particles isolated from tea buds, leaves, and stems by utilizing differences in metabolite abundance despite similar composition exhibited distinct structures and flavor attributes. Stem-derived particles exhibited mild sweetness, whereas bud/leaf-derived particles imparted pronounced bitterness and roughness; the former were porous, irregular, low surface potential, while the latter, enriched in esterified catechins and caffeine, formed larger regular octahedral aggregates. These results indicate that particle composition determines flavor potential, while assembled structures contribute to oral interfacial behavior and sensory expression. Notably, particles accounted for about 20% of the total flavor intensity by comparing sensory scores before and after removal. Collectively, this work identifies particles as critical flavor contributors in infusion systems and provides a basis for particle-driven optimization of mouthfeel and aftertaste.