Smart Colorimetric Corn Starch Films Combined with Anthocyanin-Loaded Glutenin-Carboxymethyl Chitosan Nanocomplexes for Freshness Monitoring of Chilled Pork

Abstract

In this study, intelligent, pH-responsive colorimetric films were prepared by encapsulating anthocyanins in nano-complexes prepared from glutenin and carboxymethyl chitosan. These nanocomplexes were added to a corn starch matrix and used in the freshness monitoring of chilled pork. The effects of anthocyanin-loaded nanocomplexes on the physical, structural, and functional characteristics of the films were investigated. The addition of anthocyanin-loaded nanocomplexes increased the tensile strength, elongation at break, hydrophobicity, and light transmittance of the films while decreasing their water vapor permeability. This is because new hydrogen bonds are formed between the film components, resulting in a more homogeneous and dense structure. The colorimetric film has a significant color response to pH changes. These films were used in experiments on the freshness of chilled pork, in which the pH changes with changing freshness states. The results show that the colorimetric film can monitor changes in the freshness of chilled pork in real time, where orange, pink, and green represent the fresh, secondary fresh, and putrefied states of pork, respectively. Therefore, the intelligent colorimetric film developed in this study has good application potential in the food industry.