Emulsification properties of pea protein isolate using homogenization, microfluidization and ultrasonication

- Effect of sonication on pea protein powder solubility and emulsification was studied.
- Sonication increased the dissolution rate of pea protein powder compared to stirring.
- Sonication produced a stable pea protein-oil emulsion.
- Increasing sonication time led to an increase in emulsion viscosity.
- High pressure homogenization of protein-oil mixtures led to cold-set gel emulsions.

Pea protein isolate (PPI) is used in many food formulations, due to its low cost, commercial availability and excellent amino acid profile. The objective of this study was to determine the emulsification properties of PPI. Particle size of PPI powders showed neither temperature (25-65 °C) nor time (up to 24 h) increased solubilisation of powder particles during mixing. Heating PPI dispersions (10%, w/w, protein) from 45 to 90 °C led to an increase in storage modulus (G′; Pa) at 71 °C, indicating the onset of protein aggregation. Gel formation occurred at 79 °C (G′ > 1 Pa). Pea protein-stabilised emulsions made using homogenization (15 MPa; 1 pass) or microfluidization (50 MPa; 1 pass) resulted in the formation of cold-set gels, with gel strength increasing with increasing oil concentration and fluidic pressure. Droplet size and viscosity of pea protein-stabilised emulsions decreased and increased, respectively, with increasing ultrasonication time. Overall, ultrasonication (< 50 °C) can create a uniform droplet size emulsion, while, homogenization and microfluidization can produce cold-set gels for use in a wide-range of food applications.

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