Abstract:
Hilsa kelee also known as “Karattaya” is a marine pelagic, seasonal fish species which has a high
catch during April to September. It is mainly used to produce fish meal and used as baits even
though it has high nutrients. In addition, it has a low market value and a demand due to its bony
structure leading to high wastage and production of fish protein hydrolysates (FPH) can be an
alternative. 20 mg/ml concentrated water-soluble crude protein extractions were mixed with
Protease from Bacillus licheniformis (60°C, pH 6.5-8.5), Papain from papaya latex (65°C, pH 5.8-
7.0), α-chymotrypsin from bovine pancreas (50°C, pH 7.8) and Elastase from porcine pancreas
(37°C, pH 7.8-8.5) separately in 1:100 (enzyme: substrate) ratios. Each sample was incubated at
different time intervals (0, 3, 6, 9, 12 and 24 hr) in predetermined optimum pH and temperatures.
Then, 15% SDS-PAGE was used to determine the best hydrolysis condition. Bulk hydrolysates
were prepared with Papain-6 h, Protease-3 h, α-chymotrypsin-3 h, Elastase-6 h followed with heat
inactivation at 100°C for 15 miutes for further experiments. Then, TBARS assay, Ferrous chelation
activity and antibacterial activities by agar well diffusion method was conducted. All treatments
were triplicated (n=3). According to the results obtained from TBARS assay, FPHs from papain
showed the highest antioxidant properties (5.84±0.05 MDA mg/L) compared to other treatments
(p>0.05). Fe (II) chelation activity analysis revealed the FPHs produced from α-chymotrypsin
showed the highest chelation (20.81±0.02%) (p<0.05). None of the hydrolysates showed any
antimicrobial activities for tested microorganismas up to 20,000 ppm. Thus, FPHs produced using
papain for 6 h followed with heat inactivation at 100°C for 15 miutes contain strong antioxidant
activity
Keywords: Hilsa kelee; Fish Protein Hydrolysates (FPH); Antioxidant; Metal Chelating;
Antibacterial activity
