A molecularly-guided strategy to block ethylene biosynthesis and prolong fruit shelf life

Postharvest fruit deterioration is mainly driven by ethylene accumulation, oxidative damage, water loss and microbial infection. Here, we developed a biodegradable composite film made from sodium carboxymethyl cellulose and tannic acid, named CMC@TA, for active fruit preservation. Boltz-2 predicted TA binding near the Fe²⁺-associated catalytic region of ACC oxidase. Isothermal titration calorimetry indicated TA-ACO binding (Kd = 9.93 μM), while cellular imaging showed overlapping signals. The CMC@TA film showed antioxidant, water-retention and broad-spectrum antimicrobial activities. Compared with polyethylene (PE) wrapping, CMC@TA reduced ethylene emission by 14% in bananas and 71% in hardy kiwifruits after six days. Relative to PE, CMC@TA reduced weight loss by 36-46% in climacteric and 40-45% in non-climacteric fruits, and prolonged climacteric fruit shelf life by 25-60%. Preservation improved in seven fruit species. Soil degradation, sprout growth and drinking-water exposure assays confirmed its biodegradability and biosafety. This work provides a mechanism-guided packaging strategy for reducing fruit loss.