Microstructural design of aerated food systems by soft-solid materials

- Ultra-stable foams stabilised by particles have been reported.
- This is offered by particles that can irreversibly adsorb on the air/water surface.
- This depends on their hydrophobicity, size and shape.
- Particles that do not or partially adsorb can be designed from food hydrocolloids.
- These particles also aid in stability by increasing the macro and micro rheology.

The mechanism of adsorbing particles in creating super stable bubbles has been underlined and described but designing particles with these characteristics based of food grade materials is still a challenge. Moreover, food systems are rarely “pure” and the presence of more than one functional ingredients at a given formulation is usually the norm. This highlights the importance of mixed systems where particles and surface active ingredients are present. It has been demonstrated that particles made from food based materials although often not able to stabilised foams on their own, mostly due to limitations in size and hydrophobicity, they can aid significantly in the stability of foams without their ability to adsorb on the interface being a limiting factor. Evidence is presented where particles made from protein (whey) and hydrocolloid (κ-carageenan) sources can significantly extend the life of foams by affecting the rheological properties of these systems in both a macro and micro level. The technology of creating fluid gels poses an advantage in the production of these particles in a scalable manner that can provide solutions for industrial applications that demand liquid and powder formulations. The importance of surfactants (high or low molecular weight) that are either intrinsically present or added in the systems is also being underlined. Finally, a universal mechanism is proposed which allows the design of particulate systems from soft-solid materials that can produce edible liquid foams with enhanced stability.

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