Enhanced mechanical, barrier and antioxidant properties of rice protein/sodium alginate-based films by incorporating cellulose nanocrystals and rosemary extract

This study aimed to develop rice protein (RP)/sodium alginate (SA)-based biodegradable films with excellent properties by incorporating cellulose nanocrystals (CNCs) and rosemary extract. Effects of the RP/SA weight ratio and CNCs content on the physical properties of the films were investigated, and the improved performance was illustrated by Fourier Transform Infrared spectroscopy and molecular dynamics (MD) simulation. As the RP/SA weight ratio varied from 5:0–1:1, the tensile strength (TS) of the films was increased by 143%, water vapor permeability (WVP) and oil permeability were significantly reduced by 22% and 99.2%, respectively. As the CNCs content increased to 0.3%, the TS was enhanced by 51% and the WVP was reduced by 14%. The improved mechanical and barrier properties of the films were possibly attributed to the formation of a more homogeneous and compact structure observed by scanning electron microscopy. In addition, MD simulation results revealed that there were high number of hydrogen bonds and strong electrostatic interactions in the RP/SA/CNCs/RE system, which may also lead to the improvement of mechanical and barrier properties of films. Finally, the films effectively attenuated oil oxidation. The developed films with enhanced properties are potential food packaging materials.