Physically crosslinked sodium carboxymethyl cellulose/chitosan antifungal coating for litchi preservation

Polysaccharide-based antimicrobial coatings have garnered significant attention for preservation in fruits and vegetables, but the flavor impact of essential oils as antimicrobial agents remains an issue. Herein, natamycin (NAT), which is odorless and has broad-spectrum antifungal activity, was incorporated into a physically crosslinked network of carboxymethyl cellulose sodium salt (CMCNa) and chitosan quaternary ammonium salt (HACC) to prepare antimicrobial coatings for litchi preservation. The optimal CMC-Na/HACC film formulation (CH5) exhibits outstanding barrier properties. Compared to the pure CMC-Na film (CH0), its water vapor permeability (WVP), oxygen permeability (OP), and carbon dioxide permeability (CDP) were reduced by 15.80%, 25.10%, and 15.30%, respectively. Additionally, the CH5 loaded with NAT (CH5-2N) exhibited high inhibition rates of 98.35% against S. cerevisiae and 99.50% against Peronophythora litchii. The practicability of CH5-2N as a litchi preservation coating was further investigated. The results indicate that this polysaccharide-based coating effectively inhibited litchi's spoilage and extended the shelf life of fresh litchi to 7 days at room temperature. This study highlights the significant potential of polysaccharide-based antimicrobial coatings for litchi preservation, demonstrating their broader application value in extending the shelf life of perishable foods.