Multifunctional fructose-crosslinked fibroin film with a developed β-sheet structure for advanced food packaging.

The replacement of petroleum-based plastic packaging with sustainable biopolymer-based materials is still a significant challenge. In the current study, we present a novel approach to impart the multifunctionality of fibroin film through a facile fructose-mediated crosslinking process. By generating a synergistic effect by inducing the transition to β-sheet structure and introducing covalent bonds within the fibroin chain, we effectively controlled the physicochemical characteristics of fibroin film, resulting in exceptional mechanical properties surpassing previous fibroin-based films. The fructose-crosslinked fibroin films exhibited exceptional mechanical properties, including a toughness of 3767.73 kPa and a Young's modulus of 3.06 GPa, surpassing previously reported fibroin-based films. The films also demonstrated excellent optical properties, with 98.49 % transmittance at 700 nm. Moisture stability was significantly enhanced, as the incorporation of fructose reduced water solubility by increasing β-sheet crystallinity and improved bulk water retention through its hygroscopic properties. Additionally, Maillard reaction products formed during crosslinking provided superior ultraviolet shielding and enhanced antioxidant properties, making the films ideal for active food packaging. The multifunctionality of fructose-crosslinked fibroin film significantly improves food storage stability when used in sustainable and eco-friendly food packaging applications. This high-performance fructose-mediated crosslinked fibroin film with a developed β-sheet structure emerges as a promising alternative to petroleum-based materials, offering a sustainable solution for the advanced packaging field.