Enhanced hydrophobicity, antioxidant activity, and antimicrobial efficacy of edible starch-based films incorporating pullulan and geraniol for fresh salmon preservation

The development of sustainable food packaging materials remains a critical challenge due to inherent limitations in hydrophobicity, antioxidant activity, and antimicrobial efficacy. Herein, a novel starch-based film incorporating pullulan and geraniol was designed to overcome these shortcomings through hydrogen bonding and intermolecular entanglement. Structural analyses using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed strong molecular interactions, while scanning electron microscopy (SEM) and light transmittance studies demonstrated enhanced compatibility and improved optical properties. Notably, the Starch-Pullulan-Geraniol film exhibited superior hydrophobicity, with a contact angle of 68.11°, reduced water solubility (37.56 %), and minimal water vapor permeability (1.35 ×10⁻ 10 g·m⁻ 1 ·s⁻ 1 ·Pa⁻ 1 ). Mechanical performance was also enhanced, achieving a reduced Young’s modulus of 130.34 MPa, a tensile strength of 22.66 MPa, and a maximum elongation at break of 52.81 %. Furthermore, the incorporation of pullulan and geraniol conferred remarkable antimicrobial and antioxidant properties, significantly improving the film’s effectiveness in food preservation. When applied to salmon storage, the film successfully maintained appearance, lipid stability, and microbial safety, highlighting its potential as an advanced bio-based packaging material. These findings underscore the Starch-Pullulan-Geraniol film as a promising alternative to conventional packaging, offering enhanced functionality for extending food shelf life.