Entrapping curcumin in the hydrophobic reservoir of rice proteins toward stable antioxidant nanoparticles

Loading hydrophobic phytochemicals by protein particles is challenged by either insufficient loading capacity or colloidal instability. In this study, hydrosoluble curcumin-loaded nanoparticles were prepared using hydrophobic rice proteins (RPs). The fabrication was facilitated by dissolving curcumin and RPs at pH 12.0 before neutralizing the basicity. The formation of nanoparticles was studied by fluorescence and infrared spectroscopy, and the microstructures were studied by transmission electron microscopy. The results showed the entrapping of cur cumin inside the hydrophobic reservoir formed by the acid-induced refolding of RPs. Due to promoted burial of the hydrophobic moieties, the curcumin-loaded RP-nanoparticles displayed excellent colloidal stability during the 28-day storage. Bearing 144.41 mg/g protein of curcumin, the nanoparticles demonstrated prominent antioxidant properties, with the DPPH scavenging capacity increased by up to 88.62% compared to the free curcumin. This study harnessed hydrophobic attractions as a tool for management of the protein-phytochemical interactions, overcoming colloidal instabilities of both individual components.

Automated summary

This study prepared water-soluble curcumin-loaded nanoparticles using hydrophobic rice proteins (RPs). The curcumin was entrapped inside the hydrophobic reservoir formed by the acid-induced refolding of RPs, resulting in excellent colloidal stability and prominent antioxidant properties of the nanoparticles.