Assemble behavior of ultrasound-induced quinoa protein nanoparticles and their roles on rheological properties and stability of high internal phase emulsions

This study demonstrates for the first time the use of quinoa protein nanoparticles (QPN), fabricated using ultrasonication, as a particulate stabilizer for the development of high internal phase emulsions (HIPEs). The selfassembled QPN presented a spherical appearance, and its particle size decreased with ultrasonic density, reaching a minimum size of 132 nm at 10 kJ/ml. Moreover, ultrasound treatment unfolded the compact structure of quinoa protein and endowed nanoparticles with high adsorption ability and antioxidant activity. The bioactive QPN formed stable HIPEs with internal phases of up to 89%. Furthermore, the resulting HIPEs possessed both physical and oxidative stability during storage, which could be attributed to the antioxidative physical barrier formed by the QPN. Notably, the QPN-based HIPEs exhibited higher elastic and shear thinning behavior when QPN was treated at higher ultrasonic density due to the polyhedral framework formed by compressed oil droplets. These findings provide a very promising route for new applications of quinoa protein. Furthermore, the resulting HIPEs are potential replacements for partially hydrogenated oils that may induce healthy risks.