Co-delivery of ellagic acid and essential oil via Pickering emulsion-filled polysaccharide films: Enhanced bioactivity and sustained release in biodegradable packaging.

To address environmental concerns associated with nondegradable plastics, biodegradable active packaging materials have gained attention. This study developed konjac glucomannan-chitosan quaternary ammonium salt films incorporating Pickering emulsions stabilized by whey protein isolate (WPI)-ellagic acid (EA) complexes for the co-delivery of essential oils and bioactive compounds. The emulsions exhibited optimal stability at a WPI/EA mass ratio of 4:1. The Pickering emulsion films showed enhanced mechanical strength and improved antibacterial and antioxidant activities relative to the pure polysaccharide films. Compared with the pure oil films, the 9% Pickering emulsion films reduced the cumulative release of essential oil after 7 days from approximately 81.68% to 47.72%, demonstrating an effective sustained-release effect. Among all formulations, the 6% Pickering emulsion films exhibited the best overall preservation performance, limiting strawberry weight loss to around 13.16% after 7 days. These films provide a promising solution for agricultural product preservation and biodegradable food packaging.