Preparation of modified atmosphere and antifogging packaging membranes by blending modified polyvinyl alcohol with polyester-based thermoplastic polyurethane and its application in kiwifruits

The modified atmosphere and antifogging packaging membranes were developed by blending threonine-grafted phosphorylated polyvinyl alcohol (EPT) with polyester-based thermoplastic polyurethane (TPU) via a convenient and eco-friendly blade coating method. EPT/TPU membranes containing 1% EPT demonstrated outstanding gas and moisture permeability, effectively reducing postharvest kiwifruits' respiratory activity. The CO2/O2 separation coefficient and moisture permeability of EPT/TPU membranes reached 8.20 and 133.32 g/(m2⸱24 h), respectively. Additionally, the antifogging property was attributed to a significant drop in water contact angle from 83.3° for TPU to 7° for EPT/TPU membranes. These properties contributed to maintaining a favorable atmosphere inside the package (5.3%−5.7% CO2 and 15.6%−16.0% O2) and removing moisture in time to prevent fogging, thus providing an ideal storage environment for kiwifruits and slowing down the quality deterioration. EPT/TPU membranes also had excellent mechanical properties. This modified atmosphere and antifogging membranes had broad prospects for fruit and vegetable preservation.