In Vitro Antioxidant and Antidiabetic Effects of Atlantic Mackerel and Sardine By-Product Hydrolysates

This work evaluates the effect of raw material and protease enzymes on the antioxidant and antidiabetic potential of fish by-product hydrolysates. For this, mackerel (<i>Scomber scombrus</i>) and sardine (<i>Sardina pilchardus</i>) by-products were hydrolyzed using papain, pepsin, and Protamex^TM. Pepsine produced hydrolysates with a lower degree of hydrolysis (34%) and longer peptide chain lengths (2.9), regardless of the raw material. The highest DH was found for the sardine by-products hydrolyzed with papain and Protamex^TM, exceeding 55% for both enzymes. The mackerel by-product hydrolysates exhibited higher antioxidant activity, while the sardine samples showed more potent antidiabetic effects. Accordingly, sardine by-products and pepsin would be preferable for producing hydrolysates with antidiabetic potential, and mackerel by-products, hydrolyzed papain, and Protamex^TM would be useful for producing antioxidant peptides. This study demonstrates the potential of Atlantic mackerel and sardine waste as a source of bioactive peptides and the opportunity for revalorizing these by-products.