Facile Preparation of Robust Peach Gum Polysaccharide with Remarkably Enhanced Antibacterial and Antioxidant Performance

Peach gum polysaccharide (PGP), a readily available natural polysaccharide, boasts substantial potential across diverse applications, yet its practical utility is severely limited by its vulnerability to bacterial growth and limited antioxidant activity. Herein, we introduced a simple and effective method to enhance the antibacterial and antioxidant properties of PGP by conjugating it with salicylic acid (SA). Cytotoxicity evaluation results confirmed that the resulting PGP-SA retains the excellent biocompatibility of PGP. Notably, PGP-SA demonstrates outstanding antibacterial activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, outperforming non-modified PGP. Its antibacterial mechanism is hypothesized to stem from disrupting bacterial cell membranes and proteins, targeting structures vital to microbial survival. Beyond fighting bacteria, PGP-SA also delivers robust antioxidant activity, efficiently scavenging ABTS radicals. Harnessing these dual enhancements, PGP-SA proves highly effective as a fruit preservation coating. Most impressively, it extends the post-harvest shelf life of mangoes: under identical storage conditions, PGP-SA-coated mangoes stay fresh for seven extra days compared to uncoated fruit. With its simple synthesis process and standout performance, this work not only overcomes PGP’s key limitations but also opens new avenues for its application in food preservation and related industries.