This study analyzed 32 bioactive compounds (5 catechins, 19 free amino acids (FAAs), 8 phenolics) across eight tea varieties during processing and brewing. Chemometric analyses showed that processing drove distinct compositional trends. Specifically, catechins were greatly elevated in green and white teas but reduced in black tea. Amino acids increased in white teas and some green teas, yet declined in black tea, while phenolic compounds decreased across all eight tea types. Green tea infusions exhibited the highest catechin concentrations (>600 mg/L), indicating that the abundance in dry teas is a major driver. However, inconsistencies in the trends of FAAs also suggested that other factors were involved. Kinetic modelling revealed that catechins dissolved more rapidly in green teas (JK, ET, LJ, 4.5–7.9 min) than in black/white teas (14.3–25.0 min), while FAAs showed slower dissolution (8.3–25.0 min) across all varieties. Moreover, brewing at 100 °C significantly enhanced catechin extraction for most teas, whereas MZ/MF required 80–90 °C to prevent thermal degradation. This work provides a scientific basis for optimizing tea processing conditions to maximize nutritional and sensory quality. • 32 bioactive compounds in 8 tea varieties during processing and brewing were analyzed • GT/WT retained more catechins; BT showed a decline after processing. • Two models were used to fit the brewing kinetics of these compounds. • The optimal soaking temperature for MZ/MF was 80–90 °C to avoid catechin degradation.
Dong et al. (Sun,) studied this question.