Colorimetric sensor array enabled by deep eutectic solvent-regulated anthocyanins and electrospun polylactic acid nanofiber for pork freshness monitoring.

In this study, we constructed a bilayer colorimetric sensor array with carboxymethyl cellulose, deep eutectic solvent-regulated anthocyanins, and electrospun polylactic acid nanofibers for real-time monitoring pork freshness. The nanofibers were layered over a carboxymethyl cellulose indicator layer to enhance hydrophobicity (water contact angle, 122.2°). The sensor array achieved high sensitivity (detection limit, 11.92 ppm) and stability in high-humidity environment. The chromatic response of anthocyanins was broadened through hydrogen bonding and Van der Waals interactions induced by deep eutectic solvents, which modulated their conjugated electronic structure. The sensor array exhibited robust mechanical strength (31.53 MPa), thermal stability (> 150 °C), gas responsiveness, and reusability (13 cycles). Combined with deep convolutional neural network models, the sensor array enabled precise classification and prediction of pork freshness, with the highest accuracy reaching 100 %. This intelligent sensor system paves the way for real-time meat freshness monitoring by a practical and green strategy.