Intelligent starch/chitosan-based film incorporated by anthocyanin-encapsulated amylopectin nanoparticles with high stability for food freshness monitoring

Corn starch (CS)/chitosan (CH) composite film attained higher stability by incorporating rose anthocyanins (RACNs)-encapsulated potato amylopectin nanoparticles (APNPs) as pH indicator applied for shrimp freshness detection. Apart from the physical-chemical characterization of nanoparticles, the effects of different rose anthocyanins-encapsulated by potato amylopectin nanoparticles (ANPs) contents on the mechanical strength, barrier properties and indicative performance of the films were explored. The results illustrated that the mean size of the ANPs was 192.7 nm and their zeta potential was maintained at −6.70 mV, which had the encapsulation efficiency of up to 89.7% and presented as dendritic. At the same time, the addition of ANPs formed new hydrogen bonds with matrix and a tighter network structure, improving film mechanical properties and its barrier to water vapor and light. The pH-responsive films also exhibited sensitivity to ammonia of 28.67% in 30 min and reversible pH-sensing in five alternating CH3COOH–NH3 exposure cycles. During 14-day storage, CS/CH/ANPs films showed higher stability than those with free RACNs at both 4 °C and 25 °C, whose color stability appeared positively correlated with ANPs. Meanwhile, pH-responsive films with ANPs exhibited obvious color changes from pink-colorless-yellow at 4 °C to reflect the deterioration of shrimp, foreshadowing their excellent potential in smart packaging for seafood freshness monitoring.