Preparation and physicochemical properties of antioxidant chitosan ascorbate/methylcellulose composite films

Polysaccharide-based biodegradable films have been considered as the promising candidates for food packaging industry instead of petroleum-based packaging materials. Here, we reported a class of edible composite films based on chitosan ascorbate and methylcellulose prepared by mixing different ratios (1,0, 4:1, 2:1, 1:1, 1:2, 1:4, and 0:1) of the biopolymers using the casting technique. Their physicochemical properties as well as the DPPH radical scavenging ability and reducing power were investigated. All physicochemical properties and antioxidant activities were significantly affected by the chitosan ascorbate/methylcellulose ratio in the matrix. The increases in tensile strength and elongation at break values, maximum decomposition temperatures, whitish index, compactness, moisture content, and a reduction in water vapor permeability were observed as the proportion of methylcellulose increased in the matrix. But the composite films containing a greater proportion of chitosan ascorbate exhibited the better barrier properties against UV-vis light and the stronger DPPH radical scavenging effect and reducing power. The chitosan ascorbate/methylcellulose composite films with interesting physicochemical properties and strong antioxidant action showed the potential value as biodegradable and edible biomaterials for food packaging. (C) 2019 Published by Elsevier B.V.