Development and characterization of gliadin-based bioplastic films enforced by cinnamaldehyde

Abstract

Gliadin is an ideal matrix for fabricating biodegradable bioplastic films. However, the fabricating of gliadin-based films with functional properties is still a challenge for many fields. Here, a series of gliadin-based films were prepared by crosslinking gliadin with cinnamaldehyde (CA) at different pH (pH 6.5, 7, 8, 9, & 10). Subsequently, the mechanical properties, water-resistant properties, thermal properties, antibacterial properties, and formation mechanisms of the films were systematically investigated. All the CA crosslinked films presented transparency and resistance to ultraviolet (UV) radiation. Significant increase in tensile strength (24-fold), elongation (>477%), water-resistant properties, and long-term water stability (>120 h), implying the highly crosslinking was formed in the CA crosslinked films (Schiff base, Michael's addition, and hydrogen bonds). Meanwhile, the tea polyphenols-loading properties and thermodynamic stability of the films were also enhanced by CA crosslinking under alkaline conditions. Moreover, CA crosslinked films performed splendid antimicrobial activities. The present study indicated that the overall properties of the gliadin-based films can be enhanced by the addition of CA under alkaline conditions. These results may be useful in the development of new applications for gliadin or other cereal prolamins, like drug delivery or packaging materials.