The instability of pigments and non-quantitative indication limit the application of intelligent labels in food freshness monitoring. Natural anthocyanins face challenges including photodegradation and difficulty in quantifying shrimp freshness. To solve these problems, this study prepared a colorimetric intelligent label with UV-shielding and real-time monitoring functions. Carbon-coated nano-TiO2 (C-TiO2) was synthesized by the hydrothermal method and combined with blueberry anthocyanins (BAs) in an agarose (AG)/gellan gum (GG)/glycerol matrix. The label properties were characterized and a remaining shelf-life prediction model was established based on the correlation between label color difference (ΔE) and shrimp total volatile basic nitrogen (TVB-N). The results demonstrated that C-TiO2 could enhance compatibility and color stability, and maintain mechanical properties. After 24 h of ultraviolet irradiation, the BA degradation rate was 98.4% in the GAB group and 62.8% in the GABT-0.05 group, representing a reduction of 35.6% compared to the former. This indicates that the addition of C-TiO2 significantly enhanced photostability. The predictive model demonstrated an error below 10% at both 10 °C and 20 °C conditions, indicating its potential for shelf-life prediction applications. This dual-functional label provides a reliable method for visual and quantitative evaluation of shrimp freshness.
Chen et al. (2026) studied this question.