Antioxidant Activity of Protein Hydrolysates from Redlip Mullet () Muscle and Byproducts.

Fish muscle and byproducts represent a valuable source of bioactive compounds, with their protein hydrolysates exhibiting noteworthy antioxidant properties. This study assessed the antioxidant activity of protein hydrolysates derived from the muscle and byproducts of redlip mullet (), utilizing different proteases (Neutrase, Alcalase, and Protamex). Hydrolysates were prepared from various parts of the fish, including muscle (white and red meat) and byproducts (frames, head, viscera, fins, skin, and scales). The enzymatic hydrolysis resulted in the highest degree of hydrolysis, achieving 83.24 ± 1.45% for skin at 60 min and 82.14 ± 4.35% for head at 30 min, when treated with Neutrase. Frames treated with Neutrase exhibited the highest protein concentration, measured at 1873.01 ± 71.11 µg/mL at 15 min. Significantly, skin hydrolysates treated with Protamex showed the highest DPPH• scavenging activity (70.07 ± 3.99% at 120 min), while those treated with Alcalase demonstrated the highest ABTS• scavenging activity (93.47 ± 0.02% at 15 min). The highest superoxide dismutase (SOD) activity (92.01 ± 1.47%) was observed in head hydrolysates treated with Protamex after 90 min. These results suggest that protein hydrolysates possess significant antioxidant activity within a short time frame of less than 120 min.