Effect of water-soluble antimicrobial films of carboxymethyl chitosan containing pearl powder and Tremella fuciformis polysaccharides on strawberry fresh-keeping.

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Citation abstract

Tremella fuciformis polysaccharides (TFPS) extracted from an edible fungus, with abundant hydrophilic groups, possess biological activities such as antioxidant, moisturizing, and immune-enhancing effects. Functional nanoparticles can significantly optimize the processing performance of films, so the calcium carbonate in nanopearl powder (PP) serves as a multifunctional composite auxiliary agent, exhibiting quadruple synergistic effects, namely, chelation, cross-linking, antioxidant, and antibacterial performance. This study incorporated PP and TFPS into carboxymethyl chitosan (CMCS) to develop a CMCS/TFPS/PP ternary composite film material possessing integrated properties of thermal stability, free radical scavenging capacity, and broad-spectrum antibacterial properties. The CMCS/TFPS/PP system formed a self-assembled structure through chelation, hydrogen bonding, electrostatic interaction, and amidation reactions. Specifically, compared to the pure CMCS film, the CMCS/TFPS/PP composite film demonstrated significantly enhanced properties: the derivative weight loss rate decreased by 35.15 %, water contact angle measurements indicated a 25.69 % improvement in hydrophobicity, tensile strength increased by 15.42 %, and elongation at break improved by 33.02 %. Furthermore, the composite film exhibited enhanced antioxidant performance and antibacterial activity, the antibacterial rates against E. coli and S. aureus were 91.74 % and 90.67 %, respectively. This study demonstrates that the developed composite film materials based on TFPS and PP hold significant potential for application in the field of biodegradable food packaging for fruit preservation.