Fish Waste Yields Bioactive Peptides with Blood Pressure-Lowering and Antioxidant Properties

Single-stage combined enzymatic hydrolysis (Alcalase + Protana) achieved 80% protein yield and 34-49% degree of hydrolysis, producing low-molecular-weight peptides. Hydrolysates showed ABTS antioxidant activity with EC50 below 5 mg/mL and over 60% ACE inhibition at 5 mg/mL. Gilthead seabream co-products yielded the most promising bioactive peptides.

Laboratory study testing four enzymatic hydrolysis systems (endopeptidase alone, exopeptidase alone, sequential two-stage, and combined single-stage) on co-products from three fish species. Hydrolysates evaluated for protein yield, degree of hydrolysis, molecular weight distribution, antioxidant activity (ABTS assay), ACE inhibition, and antidiabetic/anti-Alzheimer properties.

Millions of tons of fish processing waste are discarded annually. Converting this waste into bioactive peptides with health-promoting properties — particularly blood pressure management — creates value from what was previously a financial loss while addressing sustainability challenges.

This work fits into the growing field of sustainable bioactive peptide production. As demand increases for natural alternatives to pharmaceutical blood pressure and antioxidant treatments, marine-derived peptides from waste streams offer both environmental and health benefits.

In vitro study only — ACE inhibition in a test tube doesn't guarantee blood pressure reduction in humans. Bioavailability and stability of these peptides through digestion not tested. No dose-response or toxicity studies. Antidiabetic and anti-Alzheimer activities were low and likely not clinically meaningful.