Preparation, optimization and characterization of degradable mung bean starch-whey protein-apple polyphenols...

The environmental challenge posed by non-degradable plastics is initiating research into safe, biodegradable food packaging materials. This study presents the fabrication of a degradable food packaging film with antioxidant properties by incorporating apple polyphenols (AP) into a mung bean starch (MBS) and whey protein (WP) matrix. The optimal formulation of the composite film, identified through response surface methodology, comprises the MBS:WP ratio of 5:1, 37.5 wt% glycerol, and 6.5 wt% AP. Under these conditions, the MBS-WP-AP composite film exhibited key mechanical and barrier properties: tensile strength of 16.15 MPa, elongation at break of 10.03%, and water vapor permeability of 2.16 × 10^-10 gm^-1 s^-1 Pa^-1. The structure, optical properties, thermal performance, antioxidant activity, and biodegradability of the films were systematically characterized. The MBS-WP-AP composite film demonstrated excellent component compatibility, enhanced thermal stability, and significantly improved antioxidant activity, with DPPH radical scavenging activity increasing from 6.12% to 94.50% and ABTS from 8.16% to 93.23%. The composite film also retained favorable color and low opacity, and excellent biodegradability. When applied to blueberry preservation, it effectively reduced weight loss and decay incidence while stabilizing total soluble solids, thereby prolonging shelf life. These combined properties position the MBS-WP-AP film as a promising candidate for sustainable food packaging applications.