Functionality, physicochemical properties, and applications of chitosan/nano-hydroxyapatite–tea polyphenol films

An active chitosan (CS) film containing a nano-hydroxyapatite–tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products. • Slow-release CS films containing HAP-TP complexes were prepared. • The films' mechanical properties and thermal stability were enhanced by adding HAP-TP. • HAP-TP conferred good slow-release features and antioxidant effects to the CS films. • CS-HAP-TP film showed good preservation of semi-dried golden pompano. • CS-HAP-TP film wrapping facilitates the retention of the original flavor of the fish.