Thornback ray muscle hydrolysates (TRMHs) prepared by treatment with proteases from Bacillus subtilis A26
(TRMH-A26), Raja clavata crude alkaline protease extract (TRMH-Crude), Alcalase (TRMH-Alcalase) and
Neutrase (TRMH-Neutrase) were elaborated and their antioxidant properties and angiotensin I-converting enzyme
(ACE) inhibitory activities were tested. TRMHs showed different degrees of hydrolysis (DH from 11 to
22%) and hydrophobic/hydrophilic peptide ratio. Protein content varied from 71 to 74%. Gly, Pro, Asp and Asn
were the most prominent amino acids,while hypoxanthine was the major nucleotide related compound present.
The antioxidant activity was assayed using various tests. TRMH-Neutrase exhibited the highest antioxidant activity
in DPPH scavenging, reducing power and inhibition of β-carotene bleaching tests. However in the total antioxidative
efficacy, TRMH-Crude exhibited the highest activity. TRMH-Crude and TRMH-Neutrase were the most
potent to prevent DNA oxidation by Fenton reagent. Concerning anti-ACE activity, TRMH-A26 and TRMHNeutrase
exhibited the highest activitywith 87% at 5mg/ml. The results revealed that TRMHs could be employed
as a protein source in food additive processing or diets for aquatic organisms and other farmed animals.