pH-Driven formation of soy peptide nanoparticles from insoluble peptide aggregates and their application for hydrophobic active cargo delivery.

• pH-responsive behavior of insoluble soy peptide aggregates (SPA) was studied. • Soy peptide nanoparticles (SPN) were fabricated from SPA via controlled pH shifting. • SPN exhibited good storage stability and antioxidant activity. • Curcumin was effectively loaded in SPN through the pH-shifting process. • The physicochemical stability and in vitro bioavailability of curcumin were improved. The insoluble soy peptide aggregates formed upon proteolysis are generally considered as "ready to be discarded", which placed additional burden on related industries. In this study, with the aim of promoting sustainable utilization of these large aggregates, novel soy peptide-based nanoparticles (SPN) were successfully fabricated from these aggregates via a controlled pH-shifting method, and the obtained SPN exhibited good storage stability and antioxidant activity. Furthermore, the pH-shifting process also provided a driven force for loading and delivering curcumin, which significantly improved its water solubility (up to 105 folds), storage and simulated gastric-intestinal digestive stability, as well as in vitro bioavailability and antioxidant activity. These results indicated that controlled pH-shifting could be an effective and facile method to trigger the assembly of insoluble aggregates into functional peptide nanoparticles for the delivery of bioactive cargoes, which provided a new strategy for the sustainable and high-value application of these low-value peptide byproducts. [ABSTRACT FROM AUTHOR]