Colorimetric Fingerprinting of Food Antioxidants and Quality Assessment with Defect-Rich PtCu Alloy Nanozyme-Based Sensing Array

Antioxidants play critical roles in food quality, nutritional value, and health promotion, yet their rapid discrimination in complex food matrices remains challenging because of their diverse structures and redox behaviors. Herein, a defect-rich PtCu (D-PtCu) alloy nanozyme with enhanced peroxidase-like activity was developed to construct a multichannel colorimetric sensor array. By integration of three chromogenic substrates, distinct response fingerprints were generated for six representative food antioxidants. Combined with linear discriminant analysis, the sensor array achieved an accurate classification and identification of different antioxidants. Furthermore, the ascorbic acid contents determined by the proposed method agreed well with high-performance liquid chromatography (HPLC) results, and characteristic antioxidant fingerprints enabled the reliable discrimination of real food samples. This work provides a simple and rapid strategy for antioxidant profiling and food quality evaluation, demonstrating the potential of nanozyme-based sensor arrays for food analysis and nutritional assessments.