Preparation, Characterization, and Antibacterial Activity Analysis of Glycosylated Cod Fish Skin Peptide-Zinc Chelate

This study investigated the effects of glycosylation modifications on the zinc chelation capacity and Escherichia coli inhibitory activity of cod skin peptides, while elucidating the structural and property differences between maltose- and maltodextrin-derived glycosylated cod skin peptide zinc complexes. This study prepared products through Maillard reactions between maltose and maltodextrin with cod skin peptides, which were conducted over a period of 4~7 hours, followed by chelation with zinc ions. The resulting products were characterized by means of liquid chromatography and Fourier-transform infrared spectroscopy, while their antimicrobial activity was evaluated through Oxford cup diffusion assays and minimum inhibitory concentration (MIC) determinations. The results showed that the glycosylation products of the maltose system at 4 h exhibited the strongest zinc chelating ability, with an inhibition zone diameter of 17.35±0.54 mm and a minimum inhibitory concentration (MIC) of 1.10 mg/mL. For the maltodextrin system, the zinc chelating ability of glycosylation products reached the peak at 6 h, accompanied by enhanced antibacterial activity, with an inhibition zone diameter of 18.87±0.56 mm and an MIC of 0.94 mg/mL. Scanning electron microscopy images and cell membrane integrity data indicated that both systems could lyse the cell membrane of Escherichia coli and cause the leakage of intracellular components. In conclusion, both cod skin peptide zinc chelates exert antimicrobial effects by compromising the cell membranes of Escherichia coli. Notably, the maltodextrin-based formulation exhibits enhanced antimicrobial activity, thereby offering a promising foundation for the development of innovative zinc supplements and antimicrobial agents.