Biodegradable chitosan hydrogel film incorporated with polyvinyl alcohol, chitooligosaccharides, and gallic acid for potential application in food packaging

The food and beverage industry worldwide is trying to switch to using environment-friendly and bio-degradable materials in food packaging to avoid environmental concerns of using petroleum-derived plastic (synthetic polymers) materials. In this study, chitosan (CH) hydrogel films were fabricated by using its derivative chitooligosaccharides (COS) as an additive, polyvinyl alcohol as a plasticiser, and bioactive gallic acid as a cross-linker. The physical, mechanical, structural, barrier (e.g., moisture, water vapour permeability (WVP), and UV-barrier property), thermal properties, and biodegradation patterns of fabricated films were investigated. The use of bio-composite in CH films exhibited a synergistic effect. A film with a homogenous/smooth surface and excellent mechanical and thermal properties was obtained. Additionally, incorporating COS and gallic acid reduced the moisture content, WVP, and transparency. Moreover, the films exhibited good colour, strong UV-barrier properties, and good biodegradable capacity in soil. The results suggest that eco-friendly CH hydrogel films have promising potential to be used in food packaging.