Smart antibacterial packaging films prepared by TOCNC/CS nanoparticles stabilized Pickering emulsion to prolong shelf-life of fresh pork

Smart antibacterial packaging films with pH-responsiveness have the potential to reduce food spoilage and enhance food safety. In this study, composite nanoparticles were fabricated via electrostatic adsorption by adjusting the mass ratio of TEMPO-oxidized cellulose nanocrystals (TOCNC) to chitosan (CS), yielding acid-responsive TC 6 (TOCNC:CS = 6:1) and alkali-responsive TC 40 (TOCNC:CS = 40:1). Both TC 6 and TC 40 nanoparticles exhibited sensitivity to pH stimuli, as evidenced by changes in particle size, contact angle, and Zeta potential. Pickering emulsions with the oil-water ratio of 3:7 and the particle concentration of 1.5 wt% showed excellent stability and pronounced pH responsiveness. Smart antibacterial packaging films (F PTC6 and F PTC40 ) were fabricated by incorporating emulsions into the cellulose nanofibril (CNF) suspension serving as the film-forming matrix. The F PTC6 films showed sensitive response to acidic conditions, while F PTC40 films exhibited sensitive response to alkaline conditions, with 24 h cumulative cinnamaldehyde release rates of 50.7 % and 41.7 %, respectively. In addition, the smart antibacterial packaging films possessed excellent mechanical and barrier properties. Compared with pure CNF and F PTC40 films, the F PTC6 films significantly inhibited the increases in TVB-N and TVC of pork and extended pork shelf life to 9 days by responding to acidic stimuli to release active components. The developed smart antibacterial packaging films would provide a novel material and have the potential in food packaging.