## 2 Results
### Effect of Drying Temperature on the Bioactivity of LBT  
Table 6 demonstrates the DPPH radical scavenging activity and \(\alpha\)-amylase, \(\alpha\)-glucosidase, and glucose uptake inhibitory activities of the LBT at different drying temperatures. The IC\({}_{50}\) of the DPPH radical scavenging activity reached its minimum at 90 \({}^{\circ}\)C, significantly differing from the other treatments. The IC\({}_{50}\) of the \(\alpha\)-amylase inhibitory activity was significantly higher in the samples dried at high temperatures (100-130 \({}^{\circ}\)C) compared to those dried at low temperatures (70-90 \({}^{\circ}\)C). The IC\({}_{50}\) of the \(\alpha\)-glucosidase inhibitory activity increased with a rising drying temperature until reaching a maximum at 120 \({}^{\circ}\)C. The variation in the glucose transport inhibition rate with a changing drying temperature was not evident, with the IC\({}_{50}\) peaking at 70 \({}^{\circ}\)C but showing no significant difference at 90 \({}^{\circ}\)C. Overall, maintaining the biological activity of the tea could be more favorable when the drying temperatures are kept below 110 \({}^{\circ}\)C.  
The composition of the bioactive compounds in tea can be altered by the drying temperature, thereby impacting its biological activity. The relationship between non-volatile components and bioactivity indicators was further examined by a correlation analysis. As shown in Figure S4, the IC\({}_{50}\) of the DPPH radical scavenging activity exhibited a negative correlation with C. Additionally, the IC\({}_{50}\) of the \(\alpha\)-amylase activity showed a negative correlation with the tea polyphenols, soluble sugars, free amino acids, TF3\({}^{\prime}\)G, TFDG, EGC, and C, but a positive correlation with gallic acid. Moreover, the IC\({}_{50}\) of \(\alpha\)-glucosidase demonstrated a negative correlation with the soluble sugar, TF3\({}^{\prime}\)G, TFDG, EGC, and total catechins, but a positive correlation with gallic acid. Furthermore, the inhibition rate of the glucose absorption was negatively correlated with gallic acid, but positively correlated with the tea polyphenols, soluble sugar, Tf3\({}^{\prime}\)G, EGC, C, ECG, and total catechins. Among the non-volatile components, phenolic compounds such as tea polyphenols, catechins, and theaflavins are widely acknowledged as the primary inhibitors of the enzyme activity and potent antioxidants [31]. The presence of hydroxyl groups and the aromatic structure in phenolic compounds are crucial contributors to their antioxidant and free radical scavenging effects [32]. Hydroxyl groups present in polyphenols can inhibit \(\alpha\)-amylase activity by binding to its active sites. It is worth noting that theaflavins can exhibit distinct antioxidant effects [33], with the strongest inhibitory effect on the \(\alpha\)-glucosidase activity for TFDG, followed by TF3G, TF3\({}^{\prime}\)G, and TF [34]. Gallic acid has been reported as one of the active antioxidant components in black tea, with a negative correlation between its content and antioxidant activity [35]. However, in the present study, a significant positive correlation was observed between gallic acid and the IC\({}_{50}\) value of the \(\alpha\)-amylase and \(\alpha\)-glucosidase activity. Furthermore, black tea polysaccharide has been reported to exhibit a certain antioxidant capacity and a strong inhibitory effect on \(\alpha\)-glucosidase [36]. However, in this study, no significant correlation was observed between