Antioxidant, ACE-inhibitory, and antimicrobial activities of peptide fractions obtained from dried giant squid tunics

Squid tunics were divided in two batches: freeze-dried and air-dried. Dried squid tunics were directly hydrolyzed with pepsin, Alcalase, and Esperase. Freeze-dried tunics showed better aptitude for hydrolysis than air-dried tunics. Pepsin showed the lowest efficiency in protein breakdown and gave hydrolysates with low antioxidant activity, whereas Alcalase and Esperase peptide fractions showed strong radical scavenging ability, ACE-inhibitory activity, and noticeable antimicrobial properties. B. cereus, B. coagulans, and D. hansenii were found to be the most sensitive bacteria. Dried squid tunics proved to be an alternative to a previously extracted gelatin for obtaining bioactive peptides.Peer Reviewe