A nanozyme-based colorimetric platform for total antioxidant capacity evaluation: optimizing vine tea brewing with...

Vine tea, a traditional Chinese health beverage derived from Ampelopsis grossedentata, exhibits significant nutritional and medicinal value. Among its numerous bioactive compounds, dihydromyricetin (DMY) stands out as the most prominent constituent. In this study, we developed a colorimetric sensing platform to evaluate the total antioxidant capacity (TAC) of vine tea based on the oxidase-like activity of Fe₃O₄@Ag@Pt nanocomposites, using DMY as a reference standard. This method exhibited a wide linear detection range, a low detection limit (1 µM), and high accuracy with recovery rates of 97.51-102.1% in real vine tea samples. Furthermore, brewing conditions were optimized. The results revealed that extraction at 90 °C for 15 minutes maximized TAC, whereas repeated brewing (≥2 cycles) significantly reduced the antioxidant content. This study advanced the application of nanozyme-based sensing in food and pharmaceutical analysis, offering a practical approach for evaluating the TAC in flavonoid-rich samples.