Colorimetric ammonia-sensitive potato starch-based smart films containing cellulose nanocrystal and Fe-ICA complex for shrimp freshness monitoring

A new dual-functional Fe-ICA complex nanocrystal featuring intrinsic antioxidant and colorimetric ammonia-sensitive functions was designed and then combined with cellulose nanocrystal (CNC) to synergistically fortify potato starch (PS) matrix for developing advanced smart active packaging films. The influence of different Fe-ICA: CNC weight ratios on the structural, physical performances, and functional features of PS film was fully studied. Results revealed that the optimized film (PS/Fe-ICA 2 /CNC 4 ) demonstrated significantly improved mechanical strength (8.26 MPa), ductility (27.11 %), hydrophobicity (94.6°), and water/oxygen barrier performances, due to the synergistic effect of well-dispersed Fe-ICA/CNC. PS/Fe-ICA/CNC film was also endowed with potent UV-screening, antioxidant efficiency, colorimetric ammonia-sensitivity, long-term color stability, and biocompatibility. Besides, the PS/Fe-ICA/CNC film presented clear color alteration in response to shrimp spoilage, affirming its applicability for visually monitoring shrimp freshness. This work offered a new ammonia-sensitive smart packaging strategy by combining functional Fe-based complex and CNC through synergistic effects for freshness monitoring.