A Pectin-Based Active Coating for Preservation of Fresh-Cut Apples: Incorporated with Luteolin and ε-Polylysine for Enhanced Performance

Functionalized edible coatings represent a promising strategy to mitigate postharvest losses in fresh and fresh-cut fruits. This study developed a novel, ternary active coating by integrating pectin with a cationic antimicrobial polypeptide (ε-polylysine) and a hydrophobic plant flavonoid (luteolin). The resulting composite film demonstrated transformative improvements in hydrophobicity, antioxidant, and antimicrobial activities as compared with conventional pectin-based films. Specially, the ternary composite film exhibited enhanced barrier performance, reducing water vapor, oxygen and carbon dioxide permeability by 49.1%, 68.6%, and 26.5%, respectively. When applied to fresh-cut apples, the coating effectively suppressed the browning and microbial proliferation while maintaining the hardness, total phenols and flavonoids, total soluble solids, and titratable acids over a 12-day refrigerated storage period. Comprehensive characterization via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and molecular docking simulations revealed that these superior functionalities originate from synergistic electrostatic interactions and hydrogen-bonding networks within the ternary matrix. This work provides a practical strategy for designing high-performance, plant-based coatings to reduce food waste and improve the quality of fresh-cut produce.