Interfacial Engineering of High-Performance Pickering Emulsion-Gelatin Composite Films for Active Packaging

Amidst the urgent demand for sustainable alternatives to petrochemical plastics, this work incorporated oregano essential oil Pickering emulsion (AOPE; stabilizer: acetylated chitin nanocrystals (a-ChNCs)) into the gelatin matrix. Through precisely engineered hydrogen-bonding networks at the a-ChNCs/gelatin interface, achieved through the systematic optimization of AOPE concentration, a high-performance bio-based gelatin composite film (designated as GOP_X%) was developed. Low-field nuclear magnetic resonance analysis confirmed that GOP_X% containing AOPE exhibited increased hydrogen bonding crosslink density. At an AOPE loading of 6% (GOP_6%), the composite film exhibited exceptional improvements compared with GOP_0%: elongation at break increased by 107%, toughness increased by 167.5%, water vapor permeability decreased by 73.6%, and oxygen permeability reduced by 85.3%. Additionally, antibacterial and antioxidant properties were markedly enhanced. The Pickering emulsion effectively mitigated the damage of ultraviolet radiation and thermal effects on the bioactive properties of oregano essential oil. Overall, the incorporation of AOPE imparted the gelatin composite film with exceptional mechanical properties, barrier properties, antioxidant activity, and antibacterial activity, extending the shelf life of grass carp fillets by 3 days during storage. This sustainable and eco-friendly active packaging film offers a promising strategy for designing active packaging materials.