Curcumin Pickering emulsion film stabilized by guanidine-functionalized CNF for food monitoring and preservation

Guanidine-nanocellulose encapsulates curcumin forming a stable Pickering emulsion. • Emulsion encapsulation ensures curcumin stability and pH-responsive color change. • The film enables simultaneous food freshness monitoring and shelf-life extension. • The film offers an antibacterial coating for fruit surfaces that is easy to clean. Traditional food packaging suffers from drawbacks such as environmental pollution and limited functionality. Herein, we fabricated a multifunctional film based on a curcumin Pickering emulsion stabilized by cellulose nanofibrils grafted with polyhexamethylene guanidine (PCNF). PCNF acts as both a Pickering emulsifier and an antibacterial agent. The PCNF-stabilized emulsion not only protects curcumin from degradation but also forms a composite film after incorporation of PVA and glycerol. This film exhibits good mechanical strength, color stability and pH-responsive color changes. In shrimp freshness monitoring tests, the film showed a distinct color transition from pale yellow to brown. Moreover, the tunable rheology of the emulsion allows adaptable coating on fruits. After 7 days of storage, the composite coating significantly reduced banana browning, owing to its exceptional antibacterial performance. Notably, the combination of PCNF and glycerol enables rapid water disintegration. The film completely disperses within 30 s of immersion, imparting outstanding easy-cleaning properties. These synergistic features provide a robust foundation for practical applications of this material in the field of food packaging and preservation. Download: Download high-res image (264KB) Download: Download full-size image