Pioneering food analysis: Transformative antioxidant testing with colorimetric assays using Co-Mn bimetallic oxide nanozyme.

Background: Total antioxidant capacity (TAC) testing is critical for guiding dietary, and nutritional treatments, and investigating the efficacy of antioxidant food additives.

Results: Here, a competitive enzyme-like colorimetric method based on Co-Mn nanoflower nanozymes was developed for the determination of TAC in food. The synthesized nanozymes had excellent POD-like activity, using the antioxidant as a special recognition unit and the chromogenic substrate as a signal molecule reporter, and could generate a significant color response in less than 15 min by producing enzymatically catalyzed ROS. Antioxidants in food were introduced into the system and inhibited the oxidative attack of reducing substances, which was signaled through signal molecules. The established TAC sensor had a sensitivity response of 1-20 μg/mL and a low detection limit of 0.1 μg/mL. It was worth noting that the developed detection strategy not only meets the criterion of a reduced elapsed time for the HPLC method but also achieves high-throughput batch detection. The examination of each component can be accomplished in 10-20 s while maintaining the same precision as the commercially available HPLC approach.

Significance: The model designed based on simulated enzyme materials is a successful exploration of the application of nanozymes in the field of food quality testing, which will further realize the accurate and comprehensive analysis of TAC in the future.