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.

Effect of antifreeze protein on the quality and microstructure of frozen chicken breasts.

The cryo-protective effects of different concentrations of antifreeze protein (AFP, 0 %, 0.10 %, 0.15 %, 0.20 %, 0.25 %, w/v) on chicken frozen at -18 °C for different storage perispeeods were investigated by monitoring water holding capacity (WHC), water distribution, color, protein properties, microstructure and histological changes. The results showed that AFP significantly maintained the quality traits of frozen chicken. Treatment with 0.20 % AFP represented highest cryo-protective effect on the WHC and protein properties during frozen storage. The carbonyl content with 0.20 % AFP was significantly lower than that of without AFP (P < 0.05). Besides, the myofibrils of chicken supplemented with AFP, especially with 0.25 % AFP, had significantly tighter microstructure, smaller ice crystal area and equivalent diameter than those of without AFP treatment (P < 0.05) after 75 d freezing storage. Overall, AFP had a positive effect to improve the quality of frozen chicken, and it was a potential, safe and efficient cryo-protective agent.