Characterization of selenium tea polysaccharides from black tea

As an essential trace element, selenium (Se) has important biological functions, and Se-containing polysaccharides (Se-PS) have therefore received increasing attention for their unique structural features and bioactivities. In this study, Se tea polysaccharides (SeTPSs) were isolated from a Se-rich black tea and purified to obtain fractions with Se contents ranging from 146 to 572 ppb. Se content was determined by ICP-QQQ-MS, and the SeTPSs fractions were further characterized for molecular weight ( M W ) distribution, monosaccharide composition, structural features, conformation, thermal stability, and antioxidant activity. Results showed that the SeTPSs are heteropolysaccharides, with Se found in the polysaccharide material and showing Se-associated structural features, and the SeTPSs exhibited varying Se content, molecular structure, and antioxidant activity. Notably, SeTPSs demonstrated enhanced antioxidant activity and thermal stability compared to regular tea polysaccharides. These findings expand the comparative dataset for Se-rich polysaccharides and provide a foundation for future studies on organoselenium-containing macromolecules and their potential health effects. • SeTPSs isolated from a Se-rich black tea has a Se content of 146–572 ppb. • Se in SeTPSs exists as O-Se-O and Se O as evaluated by FT-IR and NMR. • Both SeTPSs and TPSs from the tea contain Man, Rha, Glc, Gal, Ara, and GalA. • Both SeTPSs and TPSs from the tea showed pronounced heterogeneity in M W. • SeTPSs showed enhanced antioxidant capacity and thermal stability.