Comprehensive characterization of theabrownin polymer structure in Tibetan tea

The intricate molecular structure of theabrownin in Tibetan tea has presented challenges in comprehending its chemical composition. To address this, our study conducted a thorough investigation into the structural features of theabrownin using advanced analytical techniques. Gel permeation chromatography confirmed theabrownin's classification as polymers, with an average molecular weight of 6200. Additionally, Py-GC/MS analysis identified 83 volatile compounds resulting from the thermal degradation of theabrownin, including esters, aldehydes, and phenols. Importantly, hydrolysis experiments, combined with high-resolution liquid chromatography-tandem mass spectrometry analysis, emphasized the crucial role of hydrochloric acid and thiolysis hydrolysis techniques in precisely elucidating the complex composition and structure of theabrownin. The hydrolyzed products verified theabrownin's composition, including jaceosidin, triethyl citrate, α-naphthoflavone, epicatechin, voriconazole, quercetin, and apigenin 7-rutinoside. These findings offer valuable insights that establish a strong scientific foundation for enhancing the quality control and refining the production processes of Tibetan tea.