Active and intelligent pH-sensing food packaging developed by incorporation of red cabbage extracts in chicken gelatin-based composite films

Abstract

Red cabbage extracts are rich in polyphenols from anthocyanins and possess potent antioxidant activity. This study, therefore, examined the active and intelligent biodegradable composite films of chicken skin gelatin and red cabbage extracts at different concentrations: 0% (film A), 1.5% (film B), 3.5% (film C), and 5.0% (film D). Incorporating red cabbage extracts into chicken skin gelatin films increased elongation at break but decreased tensile strength. The naked eye observed and differentiated colour changes, changing from light pink to cloudy and milky at pH levels 3, 7, and 10, respectively. The colour stability of the sensing film, as determined by the gas sensing evaluation of ammonia (NH3), showed that the films had excellent stability within 30 mins. Film D exhibited a higher sensing response towards NH3 by 40% with a short response time (τres) within 10 s. The antioxidant and antimicrobial activities of gelatin/red cabbage extract composite films were increased with the increase in red cabbage extract concentration, reaching 69% DPPH (2,2-diphenyl-1-picrylhydrazyl) inhibition and 19.17 mm of disc diffusion test inhibition zone on Escherichia coli. Thus, these results revealed that red cabbage extracts showed good potential to be incorporated with gelatin film as active and intelligent film packaging for food applications.