The chelation mechanism, stability and calcium absorption activity of Ruditapes philippinarum peptide‑calcium chelate

This study optimized the preparation of peptide‑calcium chelates from Ruditapes philippinarum protein (RPP). Under optimal conditions, RPP's calcium-binding capacity reached 95.79 ± 2.09 mg/g. Structural characterization (FTIR, UV, SEM) and molecular docking revealed that chelation occurred via coordination bonds, hydrophobic interactions, and hydrogen bonds (binding energy: -5.74 kcal/mol, primarily involving carboxyl oxygen atoms in a bidentate pattern. RPP-Ca demonstrated high stability, maintaining an 80%-85% calcium retention rate at pH 6.0-10.0. Furthermore, calcium transport assays showed that RPP-Ca's transport capacity was 42.20 ± 1.54% higher than that of inorganic CaCl₂. These findings indicate that RPP-Ca is a stable, high-affinity chelate with superior bioavailability, making it a promising candidate for functional calcium supplementation.