Preparation, characterization, and stability assessment of a nano-delivery system loaded with phosvitin phosphopeptide-calcium chelate

Oral digestion reduces calcium bioavailability in peptide-calcium supplements, and the construction of a nano-delivery system can solve this problem and protect peptide-calcium absorption. In this study, the delivery carrier of chitosan nanoparticles (CS NPs) was firstly optimized by particle size, polydispersity index, and Zeta potential. Then, the nano-delivery system loaded with phosvitin phosphopeptide-calcium chelate (PPP-Ca NPs) was optimized by particle size and encapsulation efficiency (EE). The results showed that the optimal EE was 87.80% ± 0.66%, and the particle size was 272.3 ± 2.4 nm. The structure characterization demonstrated that PPP-Ca NPs was mainly formed by electrostatic interaction, and the nano-delivery system was spherical particles (<100 nm). The results of in vitro digestion demonstrated that PPP-Ca NPs could improve the stability and control release of PPP-Ca. Moreover, PPP-Ca NPs could significantly improve mucoadhesion propensity, prolong residence time in the intestine, and thus enhance calcium bioavailability. Furthermore, PPP-Ca NPs could be stored for at least 90 days. This study demonstrated that this nano-delivery system with high EE of PPP-Ca NPs was stable and could protect peptide-calcium absorption. Therefore, PPP-Ca NPs have the potential to serve as a new oral calcium supplement.