Development of a pectin-based oxygen barrier coating for food packaging applications

Flexible food packaging films are challenging to recycle due to the complex multi-layer structures required for barrier properties for food protection, in a thin, transparent yet mechanically strong system. This work explores pectin as a bioderived oxygen barrier coating for polyethylene terephthalate (PET) films as a potential use case for meat packaging, targeting an oxygen transmission rate (OTR) below 1 cm 3 /m 2 .day.atm. Water-based coatings based on pectin were developed and deposited onto PET film. These coatings provided a viable oxygen barrier, reducing the OTR of 12 µm PET film from around 90 cm 3 /m 2 .day.atm when uncoated to ∼2-4 cm 3 /m 2 .day.atm when coated, a result comparable with ethylene vinyl alcohol (EVOH) currently in commercial use. Additionally, isopropyl alcohol (IPA) and graphene oxide (GO) were individually investigated as additives. GO addition was effective (OTR ≤0.7 cm 3 /m 2 .day.atm), but at the expense of reduced transparency. IPA addition resulted in the highest oxygen barrier with an OTR of ≤0.22 cm 3 /m 2 .day.atm. The tested pectin coatings were demonstrated to be water washable, allowing easy removal, leaving clean PET film for convenient recycling. This opens new opportunities for the use of PET as a viable thin film for packaging.