Hemp Seed Protein-Based Emulsion Films Containing Propolis Flavonoids: Enhanced Physicochemical Properties and Preservation of Chilled Pork

Hydrophilic colloids are ideal materials for preparing edible films; however, their intrinsic hydrophilicity leads to poor hydrophobicity in the resulting films. Emulsion-based films can significantly improve the hydrophobicity of films made from hydrophilic colloids, but this approach tends to disrupt intermolecular interactions within the film matrix. Phenolic compounds can compensate for this drawback by promoting crosslinking among film-forming polymers. In this study, hemp seed protein was used as the film-forming matrix, and rose essential oil was incorporated to prepare emulsion-based films. Different amounts of propolis flavonoids were added to investigate their effects on the physicochemical properties of the films. The results show that the addition of propolis flavonoids significantly reduced film whiteness (9%–45%), thickness (6%–37%), light transmittance (9%–60%), water vapor transmission rate (34%–65%), and peroxide value (25%–76%) of oil, while increasing tensile strength (15%–149%), elongation at break (24%–95%), Young’s modulus (26%–140%), surface hydrophobicity, thermal stability, and antioxidant and antimicrobial activities. Furthermore, pork wrapped with flavonoid-containing films exhibited inhibition of microbial growth, lipid oxidation, protein degradation, and maintained firmness. Therefore, propolis flavonoids represent a potential active ingredient for improving the physicochemical properties and preservative performance of emulsion-based films.