Fish Skin Collagen Peptides Show Antioxidant and Blood Pressure-Lowering Properties When Delivered Through Gut-Targeted Capsules | Research

The takeaway

Collagen peptides extracted from codfish skin using a novel green solvent showed antioxidant activity and 39.3% ACE inhibition, and when encapsulated in chitosan capsules, released primarily in the intestine for optimal absorption.

39.3% ACE inhibition
Codfish skin collagen peptides inhibited the blood pressure-regulating enzyme ACE, with 58% intestinal delivery via encapsulation

What the researchers found

Codfish skin collagen hydrolysates achieved 961 µmol TE antioxidant activity and 39.3% ACE inhibition. Chitosan-TPP encapsulation enabled 58% intestinal release in a simulated GI tract model.

Why it matters

Valorizing fish industry waste into health-promoting peptides addresses both sustainability and health goals. The combination of green extraction, demonstrated bioactivity, and targeted gut delivery brings this closer to a viable nutraceutical product.

The numbers in context

The extraction yielded 2.2% collagen. Antioxidant activity measured at 961 µmol TE. Enzymatic hydrolysis ran for 120 minutes.

How the study worked

In vitro study: collagen extracted from codfish skin using urea:propanoic acid (1:2) deep eutectic solvent (2.2% yield). Enzymatic hydrolysis with alcalase (120 min). Bioactivity assays for antioxidant and ACE inhibition. Encapsulation in chitosan-TPP capsules with simulated GI digestion testing.

Who was studied

Codfish skin collagen (laboratory samples)

What this study cannot tell us

In vitro study only — no human subjects. ACE inhibition of 39.3% is moderate and may not translate to clinically meaningful blood pressure reduction in vivo. The simulated GI model is simplified compared to real digestion. Long-term stability of the encapsulated peptides was not assessed.

How to read the evidence

Preliminary evidence from in vitro extraction, bioactivity, and simulated digestion studies. No animal or human validation of health effects.

When this study was published

Published in 2024. Part of the growing field of marine-derived bioactive peptides.

The bigger picture

Marine collagen peptides are a growing segment of the nutraceutical market. This study demonstrates a complete pipeline from sustainable extraction to bioactive peptide production to targeted delivery, addressing the practical challenges of bringing collagen-based health products from concept to consumer.

Questions still open

Would oral consumption of these encapsulated peptides produce measurable blood pressure reduction in humans?
How does the bioactivity of DES-extracted collagen compare to traditional acid/enzyme extraction methods?
Can this extraction process be scaled economically using real fish processing waste streams?

Common questions

Can fish skin collagen actually lower blood pressure?

In the lab, these peptides inhibited ACE — the same enzyme targeted by common blood pressure medications. However, the 39.3% inhibition rate is moderate, and it's unknown whether enough active peptide would survive digestion and reach the bloodstream at effective levels. Human studies are needed.

What is a deep eutectic solvent and why use it?

Deep eutectic solvents are mixtures of natural compounds that become liquid when combined. They're considered 'green' alternatives to harsh chemical solvents. In this study, a urea-propanoic acid mixture extracted collagen from fish skin without toxic chemicals, making the process more environmentally friendly.

Read the original research

Gastrointestinal delivery of codfish Skin-Derived collagen Hydrolysates: Deep eutectic solvent extraction and bioactivity analysis.

Food research international (Ottawa, Ont.), 175, 113729

View on PubMed ↗Publisher’s paper ↗

Citation

Silva, Isa; Vaz, Bárbara M C; Sousa, Sérgio; Pintado, Maria Manuela; Coscueta, Ezequiel R; Ventura, Sónia P M. (2024). Gastrointestinal delivery of codfish Skin-Derived collagen Hydrolysates: Deep eutectic solvent extraction and bioactivity analysis.. Food research international (Ottawa, Ont.), 175, 113729. https://doi.org/10.1016/j.foodres.2023.113729