Development of Protein-Based High-Oxygen Barrier Films Using an Industrial Manufacturing Facility.

In this study, protein-based high-oxygen barrier multilayer films were manufactured at a pilot plant scale by a roll-to-roll coating process and an adhesive lamination process. Also, their characteristics were examined to evaluate their industrial feasibility. Oxygen transmission rates (OTRs) of the protein-based films (polyethylene terephthalate [PET]/pea protein isolate [PPI]/nylon/cast polypropylene [CPP], PET/whey protein isolate [WPI]/CPP, PET/WPI/nylon/CPP, and PET/PPI/nylon/low-density polyethylene [LDPE]) were significantly lower than OTR of the PET/nylon/CPP film without a protein-coating layer and that of the commercial high-barrier multilayer film copolymer (PET/aluminum/CPP). In addition, water vapor transmission rates of the films containing protein layer were significantly lower than that of the commercial high-barrier film containing ethylene vinyl alcohol [nylon/nylon/EVOH/easy peel layer [EPL]). Among the tested polymers, the PET/WPI/nylon/LDPE film showed the highest heat-sealing ability, tensile strength, and elastic modulus. Moreover, transparency and haze of the PET/WPI/nylon/CPP film were similar to the film without WPI coating. Taken together, our results indicate that the protein-based coating films showing high-oxygen and high-water barrier properties can be manufactured using industrial facilities and could replace commercial multilayer films based on synthetic materials. PRACTICAL APPLICATION: Oxygen barrier property is an important feature in food packaging materials. Therefore, protein-coated high-oxygen barrier multilayer films were manufactured at a pilot scale to verify the possibility of their mass production. Specifically, high-oxygen and high-moisture barrier coating was produced by pea and whey proteins. Finally, the protein-based multilayer films made by an industrial facility were confirmed to be able to replace current commercial films containing synthetic barrier materials.