Enzymatic degradation of proteinaceous Pickering particles - A strategy to induce demulsification

This study aimed to understand the demulsification of Pickering emulsions using a particle dissolution approach, i.e., reducing the size of the stabilizing particles by their enzymatic degradation. We proposed that trypsin would kinetically reduce the size of model whey protein microgel particles (WPM), particle size being a key factor in reducing the desorption energy of Pickering particles leading to droplet coalescence. The capability of trypsin to digest WPM (50 vol%) was monitored under various enzyme to WPM ratios, durations of enzymatic treatment, enzyme concentrations and static versus dynamic enzyme addition. Results showed that trypsinolysis led to a notable decrease in the size of the WPM (∼40%) but not their complete dissolution. A similar trend was observed in the interfacial shear viscosity, which was kinetically driven. The trypsin-induced particle degradation resulted in droplet coalescence only at higher enzyme concentrations and demonstrated the potential of this method as a demulsification strategy.