Gas-Phase Photocatalytic Oxidation of Ethylene with TiO2-Coated Packaging Film for Horticultural Products

Abstract

Titanium dioxide (TiO2)-coated food packaging film prepared by using colloidal suspension was examined for its catalytic properties towards the photodegradation of ethylene, a primary contaminant in the package atmosphere. The TiO2 suspensions were coated onto the surface of oriented-polypropylene film (OPP) using a bar coater and dried in air; the resulting film has a milky whitish appearance. The ethylene decomposition rate increased as the TiO2 particle size was decreased. Results showed that TiO2 nanoparticles offered a larger surface area for adsorption and decomposition of ethylene and higher UV light absorption than TiO2 microparticles. Using TiO2 nanoparticles, ethylene decomposition increased as the TiO2 concentration increased from 0.1% to 10%. A Langmuir-Hinshelwood expression was used to correlate the entire set of rate data. The relative higher photocatalytic activity was obtained with the 10% TiO2 nanoparticle coated film. The application of the 10% TiO2 nanoparticle coated film on photodecomposition of ethylene in the packaging headspace of tomato fruits was also tested. The reduction of ethylene in the package atmosphere achieved by TiO2-coated film was 88% ±6% using black light lamps, while 76% ±10% reduction was achieved using fluorescent light lamps. The results suggested that the TiO2-coated film can be used as an ethylene scavenger packaging for horticultural products.