Pickering emulsions with high ionic strength resistance stabilized by pea protein isolate-polyglycerol conjugate particles with good biocompatibility

Abstract

Among various biopolymers, protein particles are widely used for stabilizing Pickering emulsions, yet their emulsifying ability are easily influenced by the ion concentration, pH, and high temperatures. To address these challenges, this study utilized chemical modification to prepare pea protein isolate-polyglycerol (PPI-PG) conjugates by Schiff-base reaction. Compared with other chemical modifications, this method produces conjugate particles with excellent biocompatibility, capable of promoting cell proliferation by up to 177 %. These conjugates showed improved dispersibility, with diffusion coefficients 3.5 times greater than pure PPI, and the isoelectric points shift from pH 4.6 to pH 1.5, which contribute to the pH stability of emulsions (pH 3–9). Additionally, the anisotropic nature of the conjugate particles, with a three-phase contact angle close to 90°, make particles need more energy for detachment from the oil-water interface, leading to good thermal stability of emulsion (80 °C, 48 h). Notably, after conjugation, these particles rely more on PG chains for dispersibility, which are less affected by ions, resulting in emulsions with high ionic strength resistance (3000 mM). Furthermore, the prepared Pickering emulsion demonstrates remarkable antioxidative properties (only a 10 % decrease), indicating widely potential applications in food, cosmetics, and pharmaceutical sectors.