Bioactive Properties of Fish Protein Hydrolysates from Amazon Sailfin Catfish (Pterygoplichthys pardalis) from the Victoria Reservoir in Sri Lanka

Pterygoplichthys pardalis is an underutilized by-catch fish species considered as an invasive fish, which is a potential threat to Sri Lankan freshwater fishery industry. This study attempted to produce bioactive fish protein hydrolysates (FPH) using P. pardalis. Acid-aided aqueous extract of fish protein was produced and the best protein extraction (PE) was selected. The lyophilized extracts were hydrolyzed using pepsin, papain and trypsin enzymes (1:100), and were subjected to analyze antioxidant properties by DPPH scavenging assay and TBARS assay, metal chelation activity and antimicrobial activity by agar well diffusion method. The 15% citric acid sample showed the highest (p<0.05) PE yield (1.95%±0.04 w/w). The pepsin (0 hour) treated hydrolysate showed the highest (p<0.05) radical scavenging activity (79.71%±5.19). None of the hydrolysates exhibited antioxidant properties against TBARS and showed no significant difference (p>0.05) in the ferrous chelating activity (pepsin (0 hour): 52.31%±0.93, papain (9 hours): 50.95%±1.17). Antibacterial activity against E. coli was positive in all hydrolysates, where pepsin (0 hour) hydrolysate showed the highest activity against E. coli. This concludes, FPHs of acidsoluble protein of P. pardalis contain antioxidant properties, iron-binding activity and antibacterial activity.