Preparation optimization, structural characterization, stability and promoting calcium absorption mechanism of sturgeon cartilage peptide-calcium chelates.

The preparation process of sturgeon cartilage peptide (SCP)‑calcium chelates (SCP-Ca) was optimized in this work, its structure, stability and promoting calcium absorption mechanism were explored. The optimum conditions for preparing SCP-Ca with Ca amount of 44.47 ± 0.87 mg/g were 50 min, 40 °C, pH of 8 and a peptide-to‑calcium mass ratio of 11:1. The C-O and -COO- groups of Asp and Glu mainly attended SCP-Ca formation, and resulted to the change of random coil and β-sheet contents in SCP. SCP-Ca showed good processing and digestive stability. SCP-Ca strengthened calcium transport volume with peak value of 1.74 ± 0.15 μg, and promoted MC3T3-E1 osteoblast mineralization by modulating RUNX2, OSX, OCN and ALP expressions. Peptides GFAGDDAPRA and EKSIDDLEDELY were potential calcium-chelating peptides of SCP, and exhibited strong binding ability with calcium absorption proteins Cav1.3 and TRPV6. This research can provide scientific basis for the utilization of SCP-Ca as novel calcium supplements.