Structure, assembly and application of novel peanut oil body protein extracts nanoparticles

Oil bodies (OBs), which are found mainly in the seeds or nuts of oleaginous plants, are spherical droplets with a triacylglycerol core covered by phospholipid-protein layer. Oil body protein extracts (OBPEs), mainly oleosins, contribute to the unique physicochemical stability of OBs. The application of OBPEs in aqueous environment has been greatly limited by their highly hydrophobic structures. In this study, OBPEs were successfully extracted from peanut seeds and their profiles were characterized by LC-MS/MS. OBPEs nanoparticles were successfully assembled in aqueous environment for the first time using the antisolvent precipitation method. The mean diameter of OBPEs nanoparticles was 215.6 ± 1.8 nm with a polydispersity index of 0.238 ± 0.005. The morphology of these colloidal particles was found to be roughly spherical shape as confirmed by transmission electron microscopy (TEM). Oil-in-water (O/W) Pickering emulsions with good stability against coalescence could be formed at protein concentration as low as 0.1 mg/mL. Cryo-scanning electron microscopy (cryo-SEM) confirmed that spherical nanoparticles were packed at the oil-water interface. This research will greatly expand the applications of OBPEs in structuring the interfaces and developing novel formulations in the food and pharmaceutical fields.