LAUSR

Abstract Response surface methodology was used to develop pH-sensitive gelatin-based films containing red cabbage extract and zinc oxide nanoparticles (ZnONPs). We also evaluated oxidized sucrose (OS), prepared via the periodate oxidation of sucrose, as a cross-linker to compensate for gelatin solubility. Solubility decreased in films containing higher OS levels. The minimum WVP of the cross-linked gelatin films was obtained at 12.8 % OS and high levels of ZnONPs. Antioxidant activity was reinforced by both ZnONPs and OS. Higher OS concentrations caused decreased opacity, while ZnONPs had the opposite effect. The optimum treatment included 0.043 % ZnONPs and 11.45 % OS. Together, ZnONPs and OS resulted in enhanced strength and decreased flexibility. Greater antimicrobial activity was witnessed against Staphylococcus aureus than Escherichia coli. The optimum film’s color changed from reddish-purple to blue-green between pH 3−12. In summary, we reinforced the gelatin film structure and achieved functional characteristics in a novel, intelligent, and active packaging material.