Formation of Phosphorylated Fish Bone Collagen Peptide-Calcium Nanoparticles in the Simulated Gastrointestinal Tract and Their Calcium Transport Characteristics

The present study aimed to investigate the optimal conditions for the formation of phosphorylated fish bone collagen peptide (PFBCP)-calcium nanoparticles in a simulated gastrointestinal tract and to evaluate their calcium transport characteristics. The calcium ion concentration required for PFBCP-calcium nanoparticle formation was determined using turbidity measurements, and the nanoparticles' characteristics were examined using particle size analysis and electron microscopy. The calcium transport effect and pathway of PFBCP-calcium nanoparticles were analyzed by constructing a Caco-2 monolayer cell model. The results showed that PFBCP could form mostly spherical, uniformly dispersed peptide-calcium nanoparticles with sizes ranging from 31 to 116 nm in a gastrointestinal simulation system containing calcium chloride concentrations of 7.5~20.0 mmol/L. With an increase in calcium chloride concentration, the particle size of PFBCP-calcium nanoparticles also increased, whereas both surface charge and surface hydrophobicity decreased. Dietary components such as casein, myofibrillar protein, chondroitin sulfate, and lecithin significantly promoted the formation of PFBCP-calcium nanoparticles in the simulated gastrointestinal system (P<0.05). PFBCP-calcium nanoparticles exhibited significantly higher levels of calcium transport than did calcium chloride (P<0.05), primarily delivering calcium through the unique pathways of endocytosis and the paracellular route, which are independent of the TRPV6 calcium ion channel. Overall, PFBCP-calcium nanoparticles formed in the gastrointestinal tract demonstrated effective calcium transport capabilities, indicating promising prospects for application development.