The Role of Organic Acid Structures in Changes of Physicochemical and Antioxidant Properties of Crosslinked Chitosan Films

This paper is devoted to replace unpleasant flavor acetic acid with organic acids to prepare high-quality chitosan film. Here, six kinds of chitosan films incorporated glacial acetic, succinic, adipic, tartaric, malic and citric acid were obtained by amidation and Maillard reactions, respectively and the physiochemical and antioxidant properties changes of acids with varying carbon chain length and functional groups on films were compared. Thermal stability, swelling degree, water vapor transmission rate and light barrier of films are significantly improved after heating, partly attributed to the formation of amide linkage in film-forming matrix confirmed by FTIR and XPS. Simultaneously, TS and EAB values present two diverse trends, further evidenced by characterizations of SEM and XRD. The presence of hydroxyl group in acid prominently increased film flexibility, slightly decreased TS and antioxidant capacity. Consequently, the crosslinked chitosan film with application-satisfied physical properties has a promising potential for food packaging.