Effect of apple polyphenols on physicochemical properties of pea starch/pulp cellulose nanofiber composite biodegradable films.

A pea starch (PS) and pulp cellulose nanofibers (CNF-P) hybrid matrix biodegradable film was prepared using apple polyphenol (AP) as the active substance. SEM and thermogravimetric analyses showed that apple polyphenols could be uniformly distributed and form hydrogen bonds with the matrix, and the increase in crystallinity improved the thermal stability of the films (the final residue of the films increased from 22.66 % to 31.82 %). The TS and EAB of the films reached their maximum values of 11.14 ± 1.73 MPa and 71.55 ± 8.8 %, respectively, at an AP content of 1.5 %. It should be noted that the antioxidant properties of the films were significantly positively correlated with the AP content, and the DPPH radical scavenging rate of the films reached 73.77 % at an AP content of 4.5 %, which was about 49 times higher than that of the control film. The same trend was observed in the UV-vis spectra. In addition, the total color difference and water solubility of the membranes increased from 4.29 ± 0.29 to 31.86 ± 1.90 and from 20.01 ± 0.97 % to 21.70 ± 1.99 %, respectively, and the biodegradability also showed an upward trend. These findings provide a theoretical basis and data support for the development of multifunctional biodegradable food packaging materials.