Model emulsions to study the mechanism of industrial mayonnaise emulsification

• A method for understanding mayonnaise emulsification mechanistically is suggested.
• Increasingly complex emulsions are processed and results compared to theory.
• As a first step, a high viscosity and high oil content emulsion is investigated.
• The high-viscosity Newtonian models follow the turbulent viscous mechanism.
• An outline for the stepwise investigation of more complex models is suggested.

Mechanistic understanding of industrial food-emulsification is necessary for optimal operation and design. Industrial mayonnaise production is yet poorly understood, partly due to a lack of experimental data and partly due to the complexity of the product.This study suggests a systematic method for building mechanistic insight, by investigating successively more complex model emulsions in industrial rotor–stator mixers, comparing to idealized theories identifying points of departure. As a first step, a high volume fraction (>50%) and high viscosity (>100 mPa s) model emulsion with a non-ionic surfactant acting as emulsifier is investigated in two industrial-scale mixers (one batch and one continuous inline mixer) at varying rotor tip-speeds.The resulting drop diameter to rotor tip-speed scaling suggest turbulent viscous fragmentation of the model emulsion in both mixers despite the high volume fraction of disperse phase which could be expected to lead to significant non-idealities such as extensive coalescence and concentration effect-dominated fragmentation. If the other non-idealities (e.g. egg yolk emulsifying system and non-Newtonian rheology) would not influence the emulsification, this suggests the same mechanism for mayonnaise emulsification. An outline for continued work on successively more complex model-emulsions is discussed in order to further enhance understanding.