Fabrication, Characterization, and Stability of Pickering Emulsions Stabilized by Lentil Protein Isolate–Gum Arabic Conjugate Microgel Particles

A new kind of lentil protein isolate (LPI)–gum Arabic (GA) conjugate was fabricated by a wet-heating Maillard reaction. The LPI-GA conjugate gel was then induced by transglutaminase (TGase) and broken into microgel particles by high pressure homogenization to stabilize the Pickering emulsion. The LPI-GA conjugate had a rough and porous flake microstructure as confirmed by scanning electron microscopy, and the LPI-GA conjugate microgel particles (LGMs) were irregular fragments and possessed good colloidal stability. The surface hydrophobicity of LGMs was lower than that of the conjugate. The microstructure images showed that LGMs wrapped the oil droplets and formed a dense coating layer. Pickering emulsions (30% oil fraction) with small droplet sizes were gel-like at particle concentrations of 10%–20% (v/v). The Pickering emulsion with 15% (v/v) particle concentration was stable at ionic concentrations (0–50 mM) and temperatures (4–85 °C) but unstable to acidic pH (3–6). Moreover, the Pickering emulsion with a high LGMs concentration exhibited good storage stability at room temperature. Overall, our findings may provide some insights into the development of a novel food-grade particulate emulsifier for stabilizing Pickering emulsions.