Enhancement of antimicrobial properties of eco-traditional teak leaf food packaging via Pickering cellulose-stabilized lemongrass oil and propolis emulsion coating

This study aimed to develop antimicrobial teak leaf-based traditional packaging by coating with a propolis-lemongrass essential oil (LEO) Pickering emulsion stabilized by cellulose nanocrystals (CNC). The coating formulation was composed of 0.8% propolis from Indonesia (A) and Brazil (B) combined with 0.5% LEO and 750 ppm CNC. Nanocellulose with rod-like morphology, characterized by atomic force microscopy (AFM), served as a stabilizing agent for oil-in-water Pickering emulsions. Confocal laser scanning microscopy (CLSM) confirmed droplet morphology with <30 μm diameters. Antibacterial assays revealed efficacy against Gram-positive ( Bacillus subtilis, Staphylococcus aureus ) and Gram-negative ( Escherichia coli, Pseudomonas aeruginosa ) bacteria. Propolis B/LEO coatings demonstrated synergistic antimicrobial activity, supported by in vivo and membrane integrity assays, extending the shelf life of leaf-wrapped rice samples until 24 h of storage according to the Indonesian Food and Drug Authority (BPOM) standard. The coatings altered leaf properties, including thickness (0.27–0.41 mm) and color difference (ΔE = 0.41–2.65). This study revealed the feasibility of food-grade Pickering emulsions for sustainable leaf-based packaging solutions.