Optimization and Characterization of Fish Protein Hydrolysate (FPH) from Milkfish Scales (Chanos chanos Forsskal) Using Papain Enzyme

This study determined that optimum fish protein hydrolysed (FPH production results from milkfish scales using crude extract of papain can be achieved by mixing 0.305 units of papain crude extract with 1 g of milkfish scales previously treated with 0.1 M NaOH (1:10 w/v). The incubation process comprised three stages: incubation at room temperature for 3 h, incubation at 75 °C for 1 h, and continued incubation at 90 °C for 5 min, with a resulting FPH yield of 45.70%. FTIR characterization revealed that FPH derived from milkfish scales includes amide A, amide I, amide II, and amide III groups. Additionally, SDS-PAGE analysis indicated that the FPH molecules measure between 10-35 kDa. The results of the study showed that FPH can inhibit the activity of E. coli and S. aureus, forming clear zones measuring 2.438 mm and 1.563 mm, respectively. Furthermore, FPH exhibited antioxidant activity against DPPH with an IC50 value of 81.91 ppm.