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

## TL;DR

This study shows that fish by-products from Atlantic mackerel and sardine can be used to make bioactive peptides with antioxidant and antidiabetic properties.

## Contribution

The study identifies optimal enzymes and raw materials for producing bioactive peptides with specific health benefits from fish by-products.

## Key findings

- Mackerel by-products hydrolyzed with papain and ProtamexTM showed higher antioxidant activity.
- Sardine by-products with pepsin produced hydrolysates with more potent antidiabetic effects.
- Sardine by-products and pepsin are preferable for antidiabetic hydrolysates, while mackerel by-products are better for antioxidants.

## Abstract

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 (Scomber scombrus) and sardine (Sardina pilchardus) by-products were hydrolyzed using papain, pepsin, and ProtamexTM. 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 ProtamexTM, 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 ProtamexTM 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.