Amino acid composition and in vitro antioxidant and cytoprotective activity of abalone viscera hydrolysate

• Abalone viscera was hydrolyzed using different enzymes.
• The ORAC and antioxidant activities of abalone viscera hydrolysates (AVH) were determined.
• AVH inhibited lipid peroxidation and DNA damage in model systems.
• AVH protected cultured hepatocytes against induced oxidative stresses.
• Amino acid composition of the AVH was determined.

Abalone viscera is one of the byproducts from abalone processing and is discarded as industrial waste. In this study, abalone viscera hydrolysates (AVH) were prepared using Alcalase, Flavourzyme, Neutrase, and Protamex, and their oxygen radical absorbance capacity (ORAC) was evaluated. The AVH by Alcalase showed promising ORAC value, and further optimal enzyme/substrate hydrolysis condition for production of the AVH was determined. The AVH also exerted strong hydrogen peroxide scavenging activity, Fe2+ chelating activity, and reducing power. Furthermore, the AVH inhibited lipid peroxidation in a model system and protected hydroxyl radical-induced DNA damage. Amino acid profiles revealed that the AVH contained 57.1% antioxidant amino acids and 44.0% hydrophobic amino acids, which contributed to its higher antioxidant activity. In addition, the AVH showed cytoprotective effects against hydrogen peroxide-induced cytotoxicity of cultured hepatocytes, and significantly (p < 0.05) inhibited intracellular reactive oxygen species (ROS) and membrane lipid peroxidation. Taken all together, these results suggest that the AVH might be useful as an ingredient for functional foods.