Deciphering composition-structure-taste relationship of black tea-infusion via assessments of nanoparticles by centrifugal treatment

Keemun tea infusion was selected as a model system under various centrifugation speeds to build a relationship among chemical composition, properties of nanoparticles in tea infusion (Tea-NPs), and tea tastes via chemical analyses, sensory evaluation, and light scattering techniques. The research results showed that the hydrodynamic radius ( R h ) of the Tea-NPs in the black tea infusion ranged from 100 to 250 nm, with a negative charge (-10 to -13 mV). The gyration radius ( R g ) and zeta-potential assessments elucidated that Tea-NPs underwent structural modifications, which altered their size, shape, and compactness. High-speed centrifugation caused the dissolution of components such as polysaccharides in the Tea-NPs, and changes in the particle compactness and aggregation altered the structure of the Tea-NPs, resulting in an increase in R h , while reducing the bitterness and enhancing the overall flavor of the tea infusion. This study highlights the important role of Tea-NPs in tea quality evaluation and their potential to drive innovative methods for improving tea product quality.