Construction of faba bean protein isolate delivery vector based on pH-driven technology: Formation mechanism, structural characterization, and delivery potential

PH-driven method has become a promising embedding method for hydrophobic active substances because of its safety and simplicity. In this study, in order to solve the application problems of quercetin (Que) such as poor water solubility and low bioavailability, faba bean protein isolate-quercetin nanoparticles with excellent embedding characteristics and delivery potential were successfully prepared by pH-driven method. Through multi-spectral and molecular docking techniques, it was showed that quercetin had a static quenching effect on faba bean protein isolate (FPI) in the alkalization stage and neutralization stage, and the mutual affinity between them changed into non-covalent interaction. In addition, according to the results of structural characterization and microscopic imaging, it was found that pH-driven changes in the secondary structure of FPI resulted in unfolding and refolding of the spatial structure, which provided an effective embedding platform for Que. At the same time, the delivery vector showed high stability and bioaccessibility in the environment of high temperature and gastrointestinal digestion, and could be effectively ingested by RAW264.7 macrophages. This study proved the potential of FPI in delivering active substances, and provided a new reference for promoting the development of quercetin precise nutrition delivery.