Development of colorimetric/Fluorescent two-channel intelligent response labels to monitor shrimp freshness

This study developed a colorimetric/fluorescent dual-channel intelligent label for real-time and visual monitoring of shrimp freshness by using the betanin (BET) and fluorescein isothiocyanate (FITC) as response signals and the corn amylose (CA) as film-forming matrix. The physicochemical properties of the as-prepared label were analyzed from the perspectives of optical properties, mechanical properties, hydration properties, crystal/chemical structure, thermal properties, and biodegradability. The addition of BET and FITC had no significant effect on other properties except for the improvement of the light barrier ability and hydrophily. The water contact angle of CA/BET/FITC label was 21.89°, and the water solubility was 29.07%. It degraded by 52% after being buried in soil for 40 days, reflecting the excellent eco-friendliness. The label produced a visually recognizable color change against pH values (8–13) and volatile ammonia (25–25000 ppm). Under daylight, the color of the label gradually changed from brick red to red, light red, orange red, brownish yellow and finally to yellow with increasing ammonia concentration. Correspondingly, the blue-green fluorescence of the label was gradually enhanced under 365 nm UV light. Further, the label was successfully used for freshness monitoring of shrimps during storage at 4 °C, 25 °C, and −20 °C. Therefore, the developed label has an extraordinary effect on controlling food quality and reducing food waste, and also provides a new idea for the development of other functionalized intelligent labels. • Betanin and fluorescein isothiocyanate were used as intelligent response signals. • The label exhibited a distinct color response under both daylight and UV light. • The label enabled colorimetric/fluorescent two-channel detection of bioamines. • The label realized real-time, visual, and in-situ monitoring of shrimp freshness.