Fractionation and identification of Alaska pollock skin collagen-derived mineral chelating peptides

Peptides with the ability to chelate dietary minerals have been reported to have potential as functional food ingredients. A collagen tryptic hydrolysate (CTH), previously shown to chelate iron, was further investigated for the presence of Ca, Fe and Cu chelating peptides. Sequential purification steps, including immobilised metal affinity chromatography (IMAC) and gel permeation chromatography (GPC) were employed for the separation of chelating peptides. GPC analysis showed that the mineral chelating peptides were mainly between 500 and 2000 Da. Subsequent identification was carried out using UPLC–ESI-QTOF MS/MS. Overall, 10 sequences were identified as potential chelating peptides. The Ca, Fe and Cu chelating activity of GPAGPHGPPG was 11.52 ± 2.23 nmol/μmol, 1.71 ± 0.17 nmol/μmol and 0.43 ± 0.02 μmol/μmol, respectively. This study identifies collagen as a good source of peptides with potential applications as functional ingredients in the management of mineral deficiencies.