Effects of polyvinyl alcohol incorporation on the physical and antioxidant properties of soy protein isolate/Xanthoceras sorbifolia husk extract active films

The design and development of biomass-based films have attracted extensive attention with the increasing demand for novel biodegradable food packaging materials. Herein, soy protein isolate (SPI) and the extracts of the waste Xanthoceras sorbifolia husk were mixed to fabricate composite films via a casting method. Polyvinyl alcohol (PVA) was further incorporated to establish ternary composite films, and the influence of PVA content (0%, 0.2%, 0.4%, 0.6%, and 0.8% w/v) on the film performance was well evaluated. The characterizations including scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), and X-ray diffraction (XRD) demonstrated the excellent compatibility and intermolecular interactions among the components after introducing appropriate PVA. Compared with the control film, the water barrier, mechanical and UV-blocking properties of the composite films were greatly improved due to the presence of PVA, especially at 0.6%. The tensile strength and the water vapor permeability of the reinforced films with 0.6% PVA addition was 10.83 MPa and 0.95 x 10- 10 g m m- 2 s- 1 Pa-1, increased by 47% and reduced by 16%, respectively. The composite films also exhibited excellent DPPH and ABTS radical scavenging capacity. Thus, the functional SPI-based films provide a feasible route for the fabrication of composite films applied for potential active packaging applications.