Active barrier chitosan films containing gallic acid based oxygen scavenger

Abstract

Active oxygen barrier films of chitosan/gallic acid/sodium carbonate (CH/GA/SC) were prepared by solution casting method. The effect of gallic acid on physical, mechanical, structural, and oxygen scavenging properties of films was investigated. As compared with neat CH film, CH/GA/SC films displayed higher thicknesses and water solubility. Tensile strength and elongation at break were affected by the addition of gallic acid and sodium carbonate. The chemical interaction evaluated by Fourier-transform infrared spectroscopy and morphology evaluated by scanning electron microscopy, and it is noticed that sodium carbonate and gallic acid were distributed homogeneously in the film structure. The X-ray diffraction confirmed that gallic acid, sodium carbonate, and chitosan had excellent compatibility. The addition of gallic acid in the chitosan matrix caused low water and oxygen permeability. The lowest oxygen transmission rate of the film was 4.10 ± 1.07 cm3/μm/m2 day kpa. The CH/GA/SC 20 film displayed the maximum oxygen-absorbing rate and capacity of 2.66 mL O2/g. day and 19.55 mL O2/g respectively, at 23 ± 2 °C. Moisture inside the package was utilized as a catalyst to begin the oxygen scavenging reaction. The results suggest that the combination of gallic acid and the sodium carbonate in chitosan film is a promising oxygen scavenging material for active oxygen barrier films.