Green Extraction and Preliminary Biological Activity of Hydrolyzed Collagen Peptides (HCPs) Obtained from Whole Undersized Unwanted Catches (Mugil cephalus L.)

What if the fish parts we throw away could heal our wounds? Scientists have found a way to turn unwanted catches into collagen peptides that boost human cell activity.

As global fish consumption rises, so do the mountains of fish waste—skin, fins, tails, and even whole undersized catches. But these discarded scraps are treasure troves of bioactive compounds. In this study, researchers extracted hydrolyzed collagen peptides (HCPs) from the grey mullet (Mugil cephalus L.) using green techniques: ultrasound and enzymes. They used two types of starting material: a mix of skin, fins, and tail, and a whole fish, mimicking real-world processing side-streams and unwanted catches.

The extraction process was efficient, yielding HCP fractions of different sizes (<3 KDa and >3 KDa) at about 5% and 0.04–0.3%, respectively. Along the way, they also isolated lipids (8–10%) and non-collagenous proteins (16–23%), adding value to every part. Each fraction was characterized using Sircol, UV-spectra, and hydroxyproline assays, and tested on human endothelial cells.

The results were striking: the <3 KDa fraction, especially at 0.13 µg/mL, significantly boosted cell viability. Even better, the T-scratch test—a measure of cell migration—showed positive effects in all fractions. This suggests these peptides could promote wound healing, turning trash into a medical treasure.

Key Points

• Green extraction (ultrasound + enzymes) from fish waste
• HCP fractions <3 KDa boost cell viability at 0.13 µg/mL
• Lipids (8-10%) and non-collagenous proteins (16-23%) also isolated