Antioxidant Properties of a Peptide-Enriched Fraction Derived from Salmon (<i>Salmo salar</i>) Bone Collagen

This study assessed the antioxidant properties of peptide mixtures extracted from salmon bones using a basic saline solution extraction process, either with ammonium hydrogen carbonate or a combination of ammonium hydrogen carbonate and ammonium hydrogen phosphate. The extracts were rich in collagen and derived peptides. After fractionating based on molecular weight, the antioxidant activity of each fraction was evaluated. ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays revealed that the extracts obtained with ammonium hydrogen carbonate solution and containing peptides below 10 kDa exhibited the highest antioxidant activity. In vitro tests confirmed that these extracts protected cells from oxidation induced by hydrogen peroxide. High resolution respirometry, a method rarely reported in other studies, demonstrated the extracts’ protective effects at the mitochondrial level. Furthermore, a preservative effect on the formation of new reactive oxygen species resulting from induced oxidative stress was observed. Mass spectrometry revealed peptides with known and predicted antioxidant motifs. This study highlights the potential of fish bones, a major byproduct of the food industry, as a valuable source of antioxidant compounds with applications in cosmetics and biomedicine, beyond their traditional use for calcium phosphate extraction.