Development of self-assembled Arachis hypogaea L. skin polyphenol-wheat starch complex-based film for sustained release, antibacterial activity, and beef quality monitoring.

Although sustainable intelligent packaging is a critical frontier in food engineering, directly introducing natural bioactives tends to compromise film mechanical properties and hamper sustained release. Herein, an active and intelligent film was engineered via a multi-level supramolecular self-assembly strategy between wheat starch and purple peanut skin polyphenols (WS/S-PSPs). Driven by intermolecular hydrogen bonding and hydrophobic inclusion, the WS/S-PSPs film exhibited increased tensile strength (from 53.21 to 60.16 MPa) and enhanced water-vapor barrier properties (WVP reduced by 23.3%) compared with the WS/S film. Fourier-transform infrared spectroscopy (FT-IR) confirmed enhanced short-range ordering, with the R1047/1016 increasing from 0.819 to 1.178. X-ray diffraction (XRD) and thermogravimetric analysis (TGA) demonstrated superior structural ordering (12.45% total crystallinity with 4.98% V-type vs. 5.66% and 0.42% for the WS/S film) and improved thermal stability (char residues rose from 8.74% to 13.33%). The non-covalent interactions effectively retarded phenolic diffusion, yielding a steady 14-day sustained release with a cumulative release of 89.27%, high radical-scavenging capacities (88.72% for DPPH and 86.27% for ABTS+ vs. 7.99% and 11.57% for the WS/S film), and notable antibacterial activity against E. coli, S. aureus, and P. fragi (inhibition zones of 10.87, 10.36, and 11.12 mm, respectively). During refrigerated beef storage, the film enabled real-time visual freshness tracking via a pH-responsive color transition correlated with total volatile basic nitrogen (TVB-N), extending meat shelf life to 12 days (vs. 8 days for the WS/S film). Overall, this non-covalent assembly strategy provides a practical approach to develop high-performance active food packaging.