Eco-friendly food packaging based on paper coated with a bio-based antibacterial coating composed of carbamate starch, calcium lignosulfonate, cellulose nanofibrils, and silver nanoparticles

Abstract

Traditional paper-based packaging commonly needs to be coated to achieve sufficient mechanical and barrier performances. In this research, a bio-based coating for paper was developed from carbamate starch (Sc), calcium lignosulfonate (CL), and cellulose nanofibrils (CNF). Controlling the electrostatic and hydrogen-bonding interactions among the components of the coating was conducive to tailoring the structure and performance of the coated paper. When the degree of substitution (Ds) of Sc was 0.10, the amount of CL was 1.00 g, and the amount of CNF was 0.65 % of the weight of Sc, the paper coated with the resulting 0.10Sc-1.00CL-0.65CNF coating exhibited increased hydrophobicity and excellent mechanical, air-barrier, and UV-light-barrier properties. After the addition of 0.10 % of silver nano-particles (AgNPs) to the 0.10Sc-1.00CL-0.65CNF coating, the paper coated with the resulting 0.10Sc-1.00CL-0.65CNF-0.10AgNPs coating exhibited good antibacterial activity against Escherichia coli and Staphylococcus aureus. The coated paper was used as the packaging for cherry tomatoes stored under ambient conditions. Due to the synergistic preservation effects of the Sc-CL-CNF coating and AgNPs, the shelf life of the cherry tomatoes was at least 7 days. The coated paper described herein has the potential for applications in the food packaging sector.