Double-Crosslinked Soy Protein Isolate Film with Improved Antibacterial and Antioxidant Performances via Introducing Phytic Acid for Packaging Beef Tallow and Chicken

Abstract

In order to improve antibacterial and antioxidant performances, phytic acid (PA) was incorporated into soy protein isolate (SPI) film crosslinked with tara tannins (TTs) and dialdehyde cellulose nanofibers (DACNFs). The resulting PDTSPI (PA/DACNF/TT/SPI) film exhibited enhanced physical and UV-Vis shielding and antioxidant properties. At 15% PA content, the tensile strength (TS) reached 5.17 MPa and the elongation at break (EB) increased to 101.15%, showing the comprehensive mechanical performance. After the addition of PA, the composite films displayed negligible light transmittance at wavelengths under 460 nm, with visible light transmittance reduced to less than 40%. And the DPPH radical scavenging rate increased to 49.2%, demonstrating strengthened antioxidant activity of PDTSPI films. Notably, increasing PA content led to improved antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with the inhibition rate of PDTSPI-12 and PDTSPI-15 films for S. aureus achieving 100%. The peroxide value (POV) of beef tallow and total viable count (TVC) of chicken packaged with PDTSPI-15 were only 0.007 g/100 g and 2.17Log CFU/g, respectively—both significantly lower than those packaged with pure SPI film, which demonstrates the potential of PDTSPI film for packaging oily foods and meat products.