Characteristics of foams produced with viscous shear thinning fluids using microchannels at high throughput

• Microchannels can be used as a continuous foaming process for the food industry.
• Fractioning of the gas phase is promoted by high velocity.
• mean bubble size down to 75 μm leads to stable foams even with void fraction of 0.55.
• Rigidity of foams exists at volume fractions lower than the “maximum compactness”.

Microchannels are used to produce food foams with the aim of obtaining void fractions and flow rates that are in accordance with food industry targets. Whey protein isolate is used as foaming agent and xanthan gum as thickening agent. At the high throughputs implemented, the shear thinning property of the fluid avoids excessive pressure drops. The tested microsystems allow mastering the foams structural properties, especially the bubble size. Stable foams are produced, even with void fraction of 0.55. Thanks to their particular structure, foams maintain their characteristics of rigidity at volume fractions lower than the maximum compactness. This outcome is also enhanced by the effect of salt on whey proteins interfacial film. The results are compared to data previously obtained with static mixers. Microchannels can be used as a continuous foaming process suitable for the food industry as well as a versatile tool for research and development in the scope of industrial expansion.