Impact of acid type for chitosan dissolution on the characteristics and biodegradability of cornstarch/chitosan based films

Biopolymers have received considerable attention in recent years given the environmental concern related to the incorrect disposal of materials based on synthetic plastics. Starch and chitosan are good examples of raw materials of interest, and its combination can exhibit some newsworthy barrier and mechanical properties. Therefore, this study aimed to determine the impact of the acid type, acetic and lactic solutions (1% v/v), used for chitosan solubilization and the starch:chitosan proportion on the properties of cornstarch/chitosan-based films. The films were prepared by casting and characterized by analyses of water vapor permeability, tensile strength, elongation, elastic modulus, antimicrobial activity, and biodegradability. Mechanical properties analyses showed that the films prepared by using acetic acid presented higher rigidity and lower deformation, giving higher values of Young's Modulus and a smaller percentage of elongation, in comparison to the films fabricated with lactic acid. Besides, starch/chitosan films containing acetic acid also exhibited better water vapor barrier properties, showing smaller water permeation values. Moreover, the antimicrobial activity of the cornstarch-based films containing chitosan was confirmed, obtaining better results for the blended films prepared with lactic acid, indicating a high potential for the development of active packaging. For the biodegradation tests, all samples started the degradation after 15 days. •Cornstarch and chitosan blended films using different acids were prepared by casting.•The chitosan incorporation promoted an improvement in mechanical properties.•Biopolymers blended films containing lactic acid presented higher water permeance.•Biopolymers blend films presented antibacterial activity against Staphylococcus aureus.•Biodegradation tests showed that all films start its degradation after 15 days.