Characterization of Chitosan-Based Active Film Incorporating with Gallic Acid

This study aims to investigate the effects of different gallic acid contents (0, 0.5, 1.0, and 1.5 mM) on the thickness (μm), moisture content (MC, %), water solubility (WS, %), water vapor permeability (WVP, mg mm/m2 h kPa), and antioxidant activity (mg Trolox equivalent (TE)/g dry film) of chitosan films. The films were prepared from chitosan (1% w/v) combined with gallic acid to reach the concentrations of 0 (control), 0.5 (GA1), 1.0 (GA2), and 1.5 mM (GA3). The thickness of the gallic acid incorporated chitosan films was not significantly different. It was in the range of 33.267 ± 9.430 to 45.100 ± 10.484 μm, with the overall average of 38.225 μm. Chitosan films with various gallic acid contents expressed similar WS, at 3.699 % in terms of overall mean. Significant differences were observed in the MC, WVP, and antioxidant capacity expressed as DPPH radical scavenging activity of the gallic acid-chitosan films. The lowest MC was found in chitosan film with 1.0 mM gallic acid (GA2) (21.042 ± 1.979 %), whereas the highest was the sample with 0.5 mM gallic acid (GA1) (32.046 ± 0.854%). As the level of gallic acid elevated, WVP of the films declined but their DPPH radical scavenging activity enhanced significantly. GA3 was chosen as the best treatment since the chitosan films at 1.5 mM gallic acid demonstrated the lowest WVP and highest antioxidant activity, at 0.833 mg mm/m2 h kPa and 13.548 mg TE/g dry film, respectively