Pore-structure-tunable carboxymethyl cellulose/polyvinyl alcohol aerogel functionalized with butterfly pea anthocyanin for real-time visual monitoring of pork freshness

This study developed a pore-tunable colorimetric aerogel based on carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and butterfly pea anthocyanin (BA) via sol-gel/freeze-drying, for real-time food freshness monitoring. The regulatory mechanisms of volume ratios on the aerogel's morphology, microstructure, physical properties, and release behavior were systematically investigated. The results demonstrated that CMC and PVA formed a stable 3D-H-bonded network, endowing the aerogel with outstanding water absorption capacity (2468.27 %), high hardness (7008.24 g), and excellent thermal stability. At a CMC/PVA ratio of 1:1, the uniform and dense pore structure modulated the BA diffusion pathways, achieving a continuous and controllable release behavior consistent with Fick diffusion kinetics. Furthermore, the BA-loaded aerogel exhibited high sensitivity to pH buffers and ammonia vapor (with a detection limit of 0.39 μM for ammonia), along with reversible color changes. During pork quality monitoring, the C1P1T (where 'C' and 'P' denote the mass of CMC and PVA, respectively, and 'T' indicates that the aerogel was loaded with BA extract) aerogel showed distinguishable color changes, clearly distinguishing between fresh, sub-fresh, and spoiled stages. This work provides a novel strategy for developing overly sensitive intelligent indicator systems for meat freshness monitoring.