Antioxidant activity and functional properties of Alcalase-hydrolyzed scallop protein hydrolysate and its role in the inhibition of cytotoxicity in vitro.

Three scallop protein hydrolysates (SPH) were obtained by enzymatic hydrolysis of scallop meal by Pepsin, Dispase and Alcalase, respectively. The antioxidant activities of the SPHs were characterized for their free radical scavenging activities through 1,1-diphenyl-2-picrylhydrazyl (DPPH)/hydroxyl/2,2' azino-bis-3-(ethylbenzthiazoline-6-sulphonic acid) (ABTS) assays, showing at least 60% radicals scavenging activities in samples (10 mg/mL). Moreover, the Alcalase-hydrolyzed SPH (ASPH) was shown to have the highest free radical scavenging activity determined by Electron Spin Resonance (ESR), due to the high proportion of antioxidant amino acids (35.25%) and better solubility. In addition, the ASPH also exhibited promising inhibitory effects (30-40%) against lipid oxidation in emulsifying system and excellent emulsifying and foaming properties. In vitro, the ASPH exhibited protective effects (nearly 20%) against H2O2-induced cytotoxicity probably due to the inhibition of mitochondria-associated generation of reactive oxygen species (ROS). The ASPH may potentially serve as a high-valued scallop-based food additive with great health benefits.