Sustainable and green design of beeswax-based pickering emulsion coating for food packaging

Beeswax, known for its natural, eco-friendly, and hydrophobic properties, has gained remarkable contributions in food industry, e.g., formulation for food packaging materials. However, challenges including high melting point, sensitivity to temperature changes, and limited fluidity hinder its broader and high-value utilization. Emulsifying beeswax offers a promising approach to address these issues. Herein, TEMPO-oxidized nanocellulose (TOCNF) with superior water dispersibility, along with carboxymethyl chitosan (CMCS) known for its film-forming and bacteriostatic properties, are utilized to stabilize beeswax particles and create an oil-in-water Pickering emulsion (PE). Complex stabilizers are formed by interaction between TOCNF and CMCS, generating protective membrane surrounding the beeswax particles. Such encapsulation prevents particle aggregation, resulting in emulsions stable without delamination even after centrifugation at 5000 rpm for 10 min and storage for over 3 months. The obtained PE is further applied to coat cellulosic paper without the need of adhesives, imparting high hydrophobicity and a certain bacteriostatic property to the paper, demonstrating efficacy in preserving fruits by slowing their decay rate. This PE system offers a sustainable and effective solution for utilizing beeswax, particularly in food packaging applications.