Development, structure characterization and stability of food grade selenium nanoparticles stabilized by tilapia polypeptides

A novel method was used to prepare selenium nanoparticles (SeNPs) in this paper. SeNPs were prepared by direct reducing the sodium selenite (Na2SeO3) using tilapia polypeptides (TP). Meanwhile, TP acted as a stabilizing agent for the SeNPs. It was found that TP-SeNPs was reduced from Na2SeO3 to element selenium then aggregated to a certain size to form a red SeNPs core, which was encapsulated by the polypeptides. We found that the formation of TP-SeNPs may induce selenium binding at the expense of the anti-parallel structure in the β-sheet structure of protein. The main bonding forces of TP-SeNPs were electrostatic interaction and hydrophobic interaction forces. It was found that the TP-SeNPs solution was relatively stable in neutral and alkaline environment. Under the condition of pH = 8, the TP-SeNPs solution showed better storage stability. •The SeNPs were formed by Na2SeO3 reduction using Tilapia polypeptides (TP).•The structure of TP-SeNPs is similar to the shell-core structure.•TP-SeNPs may induce selenium binding at the expense of the anti-parallel structure.•At pH = 8, the TP-SeNPs solution shows better storage stability.