*2.2. Preparation of Chitosan Films*

Chitosan powder was dissolved in a 0.8% (*v*/*v*) aqueous acetic acid solution to obtain a 1% (*w*/*v*) chitosan concentration by continuous stirring for 24 h. Then, 200 μL of glycerol was added to 100 mL of the chitosan/acetic acid solution. The solution was degassed for 1 h and poured into a plastic Petri plate, which was maintained in an oven at 60 ◦C for 24 h, thereby obtaining CH. The thickness of the obtained film was about 1 mm.
