PH switchable Pickering emulsion based on soy peptides functionalized calcium phosphate particles

Abstract

Here we reported a food-grade Pickering emulsions with pH switchable properties based on soy peptides functionalized calcium phosphate particles (CaP). The nanometer crystalline CaP were synthesized according to the well-established wet chemical precipitation process followed by microfluidization treatment, and functionalized in situ with a pepsin released peptides of soy β-conglycinin. These peptides characterized with a large amount of carboxyl amino acid (Glu and Asp) residues, exhibit high affinity to CaP particles. The decoration of CaP particles with soy peptides enhanced their hydrophobic wettability and electrodynamics properties simultaneously. Hence, the surface modified CaP particles facilitate to construct interfacial crystal architecture and resulting stable Pickering emulsions and gels. The pH triggered switchable properties of the emulsion were established based on the pH-dependent dissolution-recrystallization transition of CaP. Stimuli-responsive Pickering emulsification will not only offer opportunity to create a sustainable way to improve oil and catalyst recovery, but also find interesting applications in food industry for phase release of the functional elements by on-demand strategies. The food grade status of both soy peptides and calcium phosphate might extend their applications for food industry.