Antibacterial activity of tilapia protein hydrolysates chelated with metal ions

Tilapia meat protein was hydrolyzed by papain and then the hydrolysates were chelated with CaCl2and FeCl2at the mass ratio (hydrolysate:mineral salt) of 5∶1, 10∶1 and 20∶1, respectively. The antibacterial activity of the chelates was investigated. The result showed that the chelation rates were gradually increased with the increasing of the mass ratio. Amino acids analysis indicated that tilapia meat protein-hydrolysates had high content of chelating amino acids which accounted for 34.59% of total amino acid. Finally, antibacterial test showed that some chelates obtained under the certain conditions had significant antibacterial activity against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. The hydrolysate-ferrous ion chelate, which was obtained under the mass ratio of 5∶1, had the highest antibacterial activity against the three indicator bacterium.