Hydrophilic composite nanoparticles of wheat gluten protein and carboxymethyl cellulose by pH cycle and its emulsification properties for loading curcumin

Wheat gluten proteins (WPs) constitute cross-linked dough due to its physochemical properties. However, its application is limited because of its low solubility. Nutraceuticals' encapsulation inside nanoparticles to improve their bioaccessibility presents some challenges. This study aims to construct WPs-carboxymethyl cellulose (CMC) nanoparticles (WCM) by pH cycling, as well as to characterize their physicochemical properties, and assess their applicability as nanocarriers. Alkalization exposed WPs binding sites, allowing co-assembly with CMC by hydrophobic and electrostatic interactions. CMC prevents protein refolding during neutralization. Its fiber network made WCM nanoparticles' structure more orderly with moderately increased crystallinity, favoring their emulsifying function. WCM 2:1 nanoparticles with particle size of 832.40 nm and polydispersity index of 0.38 could be loaded with curcumin, increasing its in vitro bioaccessibility up to 64.68 %. This study provides more insight into pH-driven co -assembly between hydrophobic proteins and polysaccharides, contributing to their development as innovative materials and functional factor delivery carriers.