Evaluation of bioactivity of protein hydrolysate of Saurida tumbil

Fish protein hydrolysate (FPH) from lizardfish (Saurida tumbil) using papain enzyme at two concentrations of 2 and 4% at two hydrolysis times of 90 and 180 min was prepared and its antibacterial and antioxidant activity were evaluated. The antibacterial activity of FPH against pathogenic bacteria including Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Streptococcus iniae and Pseudomonas aeruginosa at different concentrations of peptide (2.34, 4.68, 9.37, 18.75, 37.5, 75, 150, 300 and 600 mg / ml) were studied using agar disc diffusion method. Also, the antioxidant activity of FPH was investigated by measuring DPPH, ABTS and OH free radical scavenging activity. Hydrolyzed proteins by the papain enzyme did not show any antibacterial activity against studied bacteria even at the highest studied FPH concentrations (3300 and 600 mg/ml). Protein hydrolysates showed remarkable antioxidant activity and the highest DPPH (43.72%), ABTS (78.64%) and OH (46.03%) free radical scavenging were observed respectively in 4% enzyme and 180 min treatments. The hydrolyzed protein of Saurida tumbil did not show antibacterial activity, but it can be considered as a natural antioxidant.