Microfluidization as Homogenization Technique in Pea Globulin-Based Emulsions

The effect of microfluidization pressure (50, 70 and 130 MPa) during emulsification on the properties of native (NP) and soluble thermally aggregated (SA) pea (Pisum sativum L.) globulin-based emulsions at neutral pH was studied. Emulsions were characterized by interfacial protein-adsorption capacity, charge, emulsifying and flocculation properties, and creaming stability. NP- and SA-based emulsions were highly flocculated. Floc size decreased when increasing the microfluidization pressure during emulsification. Shear, turbulence, and collisions due to microfluidization induced modifications in the protein/aggregate association at the O/W interface and decreased the oil droplet size. SA-based emulsions showed higher floc size and smaller oil droplet size and revealed a more effective adsorption of SA at the O/W interface than NP. Creaming stability in NP-based emulsions decreased when increasing microfluidization pressure probably as a consequence of depletion-flocculation phenomena. On the contrary, creaming stability in SA-based emulsions improved when increasing homogenization pressure as a result of the formation of a gel-like network. Microfluidization could be used to modulate the emulsifying properties of pea globulin depending on their initial denaturation state.