Aqueous radical modification of cellulose enables antioxidant Pickering emulsion coatings for fruit preservation

Postharvest fruit losses remain a major challenge, and many preservation coatings still rely on solvent-intensive processing or non-renewable additives. We report all-aqueous, ball-milling-assisted radical grafting of propyl gallate (PG) onto cellulose, producing nanofibrillar stabilizers for antioxidant Pickering coatings, avoiding organic solvents and multistep processing while integrating nanofibrillation, interfacial regulation, and antioxidant functionalization. The optimized C-PG achieves a three-phase contact angle of 87.5° and stabilizes soybean-oil emulsions with a mean droplet size of 6.41 μm and minimal growth over 30 days. Quercetin loading achieved high encapsulation efficiency (95.48%) and sustained radical-scavenging activity. As edible coatings, the emulsions delayed spoilage and mass loss in strawberries and fresh-cut apples; compared with untreated controls, QPE-C-PG6 delayed the 50% strawberry decay threshold from day 4 to 9, reduced microbial counts, preserved firmness, soluble solids, titratable acidity, and sensory quality. This fully biobased, solvent-free platform offers a scalable route to food-contact coatings for postharvest preservation.