The effects of crosslinking agents on faba bean flour–chitosan‐curcumin films and their characterization

Abstract Although glutaraldehyde (GLU) has been frequently preferred to improve some characteristics of bio‐degradable food packages, it is regarded as a hazardous chemical. Therefore, in this study, the possibility of replacement GLU with citric acid (CA) a non‐toxic compound was questioned in a film formation. Different ratios of GLU and CA on faba bean flour, chitosan, and curcumin film were examined. To determine the most favorable film composition, water solubility (WS), swelling degree (SD), water contact angle (WCA), water vapor permeability (WVP), and mechanical properties of the films were examined. In addition, the effects of crosslinking agent and their ratios on crystallinity (XRD), thermal properties (DSC and TGA), and antioxidant activity (DPPH and ABTS) were also studied. Time Domain Nuclear Magnetic Resonance (TD‐ NMR) relaxometry was also employed to explain distribution and mobility of the protons in faba bean flour, chitosan, and curcumin films. At the end of the analysis, it was concluded that CA and GLU reduced SD by 75% and 13% compared to the films without cross‐linker, respectively. Incorporation of crosslinking agent increased the WCA from 77.22° to 99.41° and caused formation of more hydrophobic surfaces. Increasing both crosslinking ratios restricted the permeance drastically which was more than 110%. Furthermore, the lowest WVP was measured for the films containing CA at 1.5% w/v ratio (FC‐1.5C). While GLU improved the tensile strength (TS) of the film, lower elongation of the films caused formation of brittle character which limited the utilization of the films. At the end of the analysis, it was concluded that FC‐1.5 had more feasible character with respect to the other films and CA was suggested as a crosslinking agent instead of GLU for faba bean‐chitosan films.