Full-Spectrum HPLC-DAD digitization combines chemical and antioxidant fingerprints for quality control of big red...

Conventional quality control protocols for foods and medicinal products seldom integrate chemical fingerprints with bioactivity readouts, limiting their discriminative power for complex matrices. We developed a digitalization workflow that employs full-spectrum temporal-integration analysis (FTIA) and three-dimensional peak-max projection method (3D-PMPM) on HPLC-DAD data for big red robe tea. The 200-400 nm spectral cube is compressed by FTIA and 3D-PMPM and then evaluated against a reference using a binary evaluation system (BES; S_m, P_m). A post-column on-line ABTS assay produced time-aligned antioxidant fingerprints. A six-parameter "5 + 2" bracketing check verified sequence stability. Median-based activity maps located robust hotspots at peaks P2-P3 and P12; an abundance-weighted Antioxidant Activity Index provided consistent lot ranking. Process screening showed that mild citric acid (0.60-0.85%) with a 1:50 solid-liquid ratio and 20-30 min ultrasonication maximized the digital fingerprints. The workflow delivers quality control-ready, auditable metrics that co-register spectral fingerprints, composition, and antioxidant activity, and is transferable to other foods.