Apparent Interfacial Tension Effects in Protein Stabilized Emulsions Prepared with Microstructured Systems

Area of Science:

• Food Science and Technology
• Colloid and Surface Science
• Chemical Engineering

Background:

• Proteins are crucial for stabilizing food emulsions, but their complex interfacial behavior complicates scaling relations.
• Existing emulsification processes face challenges in predicting and controlling emulsion properties due to protein dynamics.

Purpose of the Study:

• To develop a robust scaling relation for protein-stabilized emulsions using premix membrane emulsification.
• To investigate the influence of protein type (whey protein, bovine serum albumin) and concentration on emulsion characteristics.
• To compare the performance of proteins against standard surfactants (Tween 20) in controlling emulsion droplet size.

Main Methods:

• Utilized premix membrane emulsification with whey protein, bovine serum albumin (BSA), and Tween 20 at varying concentrations.
• Employed microfluidic Y-junctions to estimate apparent interfacial tension under relevant throughputs.
• Derived a scaling relation based on the Ohnesorge number and P-ratio, analyzing the interplay of viscous, inertia, and interfacial tension forces.

Main Results:

• A unifying relation was found for apparent interfacial tension, enabling the Ohnesorge number to be plotted against the P-ratio.
• A consistent decrease in the Ohnesorge number was observed with increasing P-ratio for all tested emulsifiers.
• Proteins showed systematic differences compared to surfactants, with surfactants being more effective in reducing droplet size, likely due to protein visco-elastic film formation.

Conclusions:

• The developed scaling relation provides a more accurate framework for understanding protein-based emulsions.
• Protein interfacial behavior, specifically visco-elastic film formation, significantly impacts emulsion properties compared to conventional surfactants.
• Whey protein and BSA exhibited similar behaviors, particularly at lower concentrations, and differed from higher concentrations of Tween 20.