Calcium-Chelating Properties of Chicken Bone Collagen Peptide and Calcium Absorption Activity of Its Chelate in Caco-2 Cells

Calcium malabsorption and low in vitro apparent calcium transport efficiency of conventional calcium supplements remain critical and urgent public nutritional challenges worldwide. In this study, chicken bone collagen peptides (CBCP) were prepared via an optimized ultrasound-assisted stepwise enzymatic hydrolysis, forming structurally stable calcium chelates with a high calcium-chelating capacity of 112.50 ± 5.62 μg/mg. Through LC-MS/MS peptidomic profiling of CBCP hydrolyzate, a decapeptide DFSFLPQPPQ accounting for 11.50% of all quantified collagen-derived peptides was characterized. The decapeptide DFSFLPQPPQ was prioritized by LC-MS/MS peptidomic profiling and in silico docking against the calcium-sensing receptor (CaSR). In Caco-2 cell monolayers, DFSFLPQPPQ-Ca and CBCP-Ca showed apparent calcium transport efficiencies of 44.33% and 47.42%, respectively, under their corresponding test conditions. These findings support the calcium-transport-promoting activity of the two peptide-calcium systems.