Pea protein exhibits a novel Pickering stabilization for oil-in-water emulsions at pH 3.0

•Pea protein isolate (PPI) at pH 3.0 was present in the nanoparticle form with sizes of 100-200 nm.•The PPI emulsions at pH 3.0 exhibited similar characteristics to classic Pickering emulsions.•Increasing the concentration (c) progressively reduced the emulsion size.•These emulsions exhibited excellent stability against coalescence and even creaming.•The improvement of creaming stability was closely due to the formation of flocculated droplet network.

In this paper we reported that pea protein isolate (PPI) at pH 3.0 exhibits a novel Pickering stabilization for oil-in-water emulsions. At pH 3.0, most of the proteins in PPI were present in the nanoparticle form, with the hydrodynamic diameter of 134-165 nm depending on the concentration (c; 0.25-3.0 g/100 mL). For the emulsions formed at a specific oil fraction of 0.2, increasing the c from 0.25 to 3.0 g/100 mL resulted in a considerable reduction in the emulsion size, while their creaming stability progressively increased, and especially at c values higher than 2 g/100 mL, no creaming occurred even after storage of 20 days. Confocal laser scanning microscopy observations showed that increasing the c resulted in a progressive increase in extent of droplet flocculation, and at higher c values, a network consisting of flocculated droplets could be formed. The emulsions formed at c values above 1.0 g/100 mL exhibited extraordinary stability against coalescence. The flocculated droplet network formation was closely associated with the increased amount of adsorbed proteins at the interface. The results suggest that pea proteins exhibit a good potential to act as a kind of Pickering stabilizers for oil-in-water emulsions at acidic pHs.