Development and characterization of chitosan/guar gum active packaging containing walnut green husk extract and its application on fresh-cut apple preservation

The aim of this work was to develop active packaging film by using chitosan/guar gum (CG) film matrix and walnut green husk extract (WE), for preservation of fresh-cut apple. WE was used as cross-linking agent to improve physicochemical properties, and as active substances to enhance antioxidant activity of CG films. Fourier transform infrared spectroscopy and scanning electron microscopy results showed WE formed intermolecular hydrogen bond interactions with the film matrix, and microstructures of the film were more compact. With the increase of WE content (0-4 wt%), the mechanical properties of composite films were significantly enhanced, while permeability of water vapor and oxygen was significantly decreased (p < 0.05). When the amount of extract reached 4 wt%, the DPPH radical scavenging activity of composite film was significantly increased to 94.59%. CG-WE and CG films were used as active packaging materials to preserve fresh-cut apple. When stored at 4 ? for 10 days, CG-WE films showed better performance in reducing firmness, weight loss, total soluble solids and inhibiting browning and microbial growth of fresh-cut apples. Therefore, as a new type of active food packaging material, CG-WE films have good physical properties, and great potential in ensuring food quality and extending shelf life.

Automated summary

The aim of this study was to develop active packaging film for fresh-cut apple preservation using chitosan/guar gum film matrix and walnut green husk extract. The addition of walnut green husk extract improved the physicochemical properties of the film and enhanced its antioxidant activity. The results showed that the mechanical properties of the composite films were significantly enhanced by the addition of the extract, while the permeability of water vapor and oxygen was significantly reduced. The study also found that the addition of walnut green husk extract effectively preserved the freshness of the apple, reducing firmness and weight loss, and inhibiting browning and microbial growth of the apple slices.