Physical properties and bioactivities of chitosan/gelatin-based films loaded with tannic acid and its application on the preservation of fresh-cut apples

The aim of this research is to develop composite (CG-TA) films by using chitosan (CS)/gelatin (GL)/tannic acid (TA), for fresh-cut apples preservation. TA was used as the crossing-linking agent to improve the mechanical and barrier properties, and as the active substance to improve the anti-ultraviolet and antioxidant abilities of the chitosan/gelatin (CG) film. With the incorporation of TA from 0 to 1 wt%, the tensile strength of the CG film was increased while the water vapor and oxygen permeability of the film were decreased. The CG-TA films containing more than 0.5 wt% of TA could effectively block most of UV light. The DPPH radical scavenging assay significant increased to 89.3% when the concentration of TA reached 2 wt%. Finally, CG and CG-TA films, as an active packaging material, were used to preserve the cold-stored fresh-cut apples. Compared with CG film, the CG-TA films obtained better performance on decreasing weight loss, delaying browning degree, inhibiting the lipid oxidase activity and decreasing the malondialdehyde content during 10 d of storage under 4 degrees C. Therefore, CG-TA films were expected to be a new active packaging material for preserving fresh-cut apples.

Automated summary

The study developed composite films using chitosan/gelatin/tannic acid for fresh-cut apples preservation. Tannic acid improved mechanical and barrier properties, decreased water vapor and oxygen permeability, blocked UV light, enhanced antioxidant ability, and reduced weight loss and oxidative reactions in stored apples.