Time-resolved dual nanozyme colorimetric array for antioxidant fingerprinting and beverage shelf-life assessment

Accurate detection and quantification of antioxidants are vital for human health and food safety. Here a colorimetric sensor array was developed to detect and quantify 8-typical antioxidants using two core-shell gold-nanostar (AuNS) nanozymes: AuNS@CuO and AuNS@FeS. These were synthesized via a seed growth method and coated with CuO or FeS layers. Both exhibit peroxidase-like activity, catalyzing TMB oxidation by H₂O₂. Different antioxidants inhibit this reaction to varying degrees, producing distinct absorbance patterns (fingerprints) measured at different time points. By means of linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA), the designed colorimetric sensor array was capable of precisely identifying eight kinds of antioxidants within the concentration range of 15-1000 μM, and accurately discriminating mixtures composed of 2-3 kinds of antioxidants. The method was applied to monitor beverage quality, distinguishing soft drinks of different production dates and shelf lives by tracking changes in antioxidant profiles. This work presents a rapid and universal platform based on colorimetric sensors for the precise identification of antioxidants, offering strong potential for the rapid screening of the freshness and safety of liquid beverages with minimal sample preparation.