Antibacterial activity and action mechanism of a novel chitosan oligosaccharide-hydroxypyridinone conjugate and its application in shrimp preservation.

Abstract

To develop new antibacterial agents with the potential application in shrimp preservation, a novel chitosan oligosaccharide (COS)-hydroxypyridinone (HPO) conjugate (COS-HPO2) with strong antioxidant and anti-tyrosinase activities was investigated for its preservation effect on shrimp. The antibacterial activity assay indicated that COS-HPO2 possessed greater antibacterial activity than COS against five bacterial strains (Staphylococcus aureus, Listeria monocytogenes, Shewanella putrefaciens, Escherichia coli and Pseudomonas aeruginosa). The antibacterial mechanism survey against S. putrefaciens RMS1 revealed that COS-HPO2 could increase cellular permeability, resulting in the leakage of intracellular substances. COS-HPO2 could also kill the bacteria by chelating iron ions in the environment and inhibiting DNA replication. The treatment with COS-HPO2 was found to extend the shelf life of shrimp to 10 days at 4 °C, whereas the shelf life of shrimp treated with COS, ε-polylysine (ε-PL) and the control group was 8, 8 and 5 days, respectively. Treatment of shrimp with a formulation containing COS-HPO2 and ε-PL (1 g L-1) further extended its shelf life to 12 days. COS-HPO2 could find application in shrimp preservation. © 2025 Society of Chemical Industry.