Study on the barrier properties and antibacterial properties of cellulose-based multilayer coated paperboard used for fast food packaging

Some petroleum-based packaging materials have a series of safety issues, and as a result, people are more inclined to use biodegradable and nontoxic packaging materials for foods. However, biodegradable alternatives often need to be modified to overcome their own shortcomings. In this paper, carboxymethyl chitosan (CMCS)/carboxymethyl cellulose sodium (CMC) + polylactic acid (PLA) nano zinc oxide (ZnO) nanoparticles (CMCS/CMC + PLA/ZnO NPs) multilayer coated paperboard was prepared to explore its potential use in food package applications. The multilayer CMCS/CMC + PLA coating reduced the oxygen transmission rate by 99% and doubled the barrier properties for soybean oil penetration and water vapor compared with a single PLA coating layer in a 23 degrees C/50 RH environment. The oil resistance time of the multilayer CMCS/CMC + PLA coating also increased 28 times, and the water vapor barrier properties increased twofold compared to a single CMCS/CMC coating layer. The water vapor barrier properties increased by a factor of 3 even at 38 degrees C/90 RH. Compared with the CMCS/CMC + PLA coating without nanoparticles, the barrier performance of the CMCS/CMC + PLA/ZnO NPs coating was further improved. The oxygen, water vapor, and heptane vapor barrier properties all doubled, and the oil resistance time reached 235 h. While a corona treatment reduced the polar component content in the CMCS/CMC coating and led to a slight decrease in the barrier properties of the coating to heptane, it was still a good oil-repellent coating overall. The antibacterial activity (A) toward Escherichia coli and Staphylococcus aureus exceeded 2, which meant that the multilayer coating with 1.5% added ZnO NPs reduced the growth of bacteria by more than 99%. The multilayer coated paperboard created here with the blended and modified materials significantly improved the barrier and antibacterial properties, suggesting that multilayer coatings prepared from degradable materials have good commercial prospects as fast food packaging.

Automated summary

A new type of food packaging material with excellent oxygen, water vapor, and oil barrier properties, as well as antibacterial activity, was developed in this study, showing great commercial prospects.