Preparation and performance testing of corn starch/pullulan/gallic acid multicomponent composite films for active food packaging

The present study investigated the mechanical characteristics, hydrophobicity, antioxidant and antibacterial properties, FTIR, SEM and XRD of films fabricated with corn starch and pullulan (CS/PUL) by adding different concentrations of Gallic acid (GA) (0%, 0.5%, 1.0%, 1.5% w/v). The mechanical strength and opacity of CS/PUL films were enhanced by the addition of 1.0% GA. The water vapor permeability (WVP) of CS/PUL films was significantly lower in films with GA compared to those without (P < 0.05). The addition of GA, especially at concentrations of 1.0% and 1.5%, resulted in considerably better free radical scavenging activities on DPPH than films without GA (P < 0.05). Interestingly, the highest water contact angle (WCA) value was observed in films with 0.5% GA, indicating stronger hydrophobicity. Furthermore, the antibacterial capabilities of the films, particularly against E. coli and P. aeruginosa, improved with an increase in GA concentration. The results of FTIR, SEM and XRD analyses showed that GA was well distributed in the CS/PUL matrix.

Automated summary

This study investigated the effects of adding different concentrations of Gallic acid (GA) (0%, 0.5%, 1.0%, 1.5% w/v) to films fabricated with corn starch and pullulan (CS/PUL) on their mechanical characteristics, hydrophobicity, antioxidant and antibacterial properties, FTIR, SEM and XRD. The addition of 1.0% GA enhanced the mechanical strength and opacity of CS/PUL films. Films with GA exhibited significantly lower water vapor permeability (WVP) than those without. The addition of GA, especially at concentrations of 1.0% and 1.5%, resulted in better free radical scavenging activities on DPPH and improved antibacterial capabilities against E. coli and P. aeruginosa.