A novel polysaccharide-based approach from macromolecular interactions: control of postharvest Botrytis cinerea by...

Fresh fruits are highly favored by consumers due to their appealing flavor and rich nutritional value. However, significant postharvest losses occur due to physiological senescence and fungal pathogen infection. Therefore, it is imperative to develop high-performance, sustainable active coatings for postharvest fruit preservation. In this study, phase separation analysis revealed that mannoproteins (MPs), sodium alginate (SA), and their binary complexes exhibited antimicrobial properties through binding with β-tubulin of Botrytis cinerea, thereby inhibiting mycelial growth, development, and spore release of the B. cinerea. Subsequently, a dual-molecule interpenetrating network coating was constructed based on this mechanism. Results demonstrated that SA and MPs formed entangled structures through hydrogen bonding interactions, establishing a natural barrier on grape surfaces. This barrier effectively prevented pathogen invasion, maintained grape moisture, firmness, delayed senescence, and controlled postharvest diseases during storage. Collectively, the utilization of biomass-derived MPs and natural polysaccharide SA in coating formulation provides an economically viable and sustainable approach for functionalizing biomass materials toward fruit preservation.