Chitosan/sodium tripolyphosphate nanoparticles as efficient vehicles for antioxidant peptidic fraction from common kilka.

Fish-purified antioxidant peptide (AOP)-loaded chitosan nanoparticles (CSNPs) were synthesized based on the ionotropic gelation between CS and sodium tripolyphosphate (TPP). The ζ-potential showed an earlier rise and later decrease with increasing concentrations of AOP. Transmission electron microscopy (TEM) images also revealed roughly uniform spherical-shaped nanoparticles with diameter of <100 nm. Molecular interactions among the components of the NPs and peptides were confirmed by FT-IR spectroscopy. Thermo-gravimetric analysis (TGA) results showed the improved thermal stability of the AOP-loaded CSNPs compared with free peptides. The maximum peptide encapsulation efficiency was determined to be 71.16% and the in vitro release of peptides from CSNPs was in a controllable manner. Furthermore, assessing the free radical scavenging ability of the peptide-encapsulated NPs and the reducing power assay, confirmed the efficacy of such nanosystem in retaining the antioxidant activity of fish-derived peptides.