The process devised by food technologists from the University of Manchester can also be used for producing an array of products that can improve upon the creamy topping required for a perfect flat white coffee, plus completely different products, such as shampoos. Other applications include firefighting foams of better consistency plus oil absorbent foams used to address ecologically harmful oil spills.
A complication with foam made from two or more additives is with controlling the amount of foam produced. To tackle this, the researchers examined mixtures containing surfactant and a polymer to develop a new mechanism for understanding how two samples interact, so they could create the ideal foam.
Liquid foams are non-equilibrium dispersions of gas in a liquid that are stabilized against drainage and collapse by surface active agents
The solution lay with developing a means to reflect neutrons off various liquid samples. This provided the means to examine the stability of foam films, considering the different means by which additives self-arrange at the surface of the liquid coating of bubbles. The focus was on creating stable conditions to prevent bubbles from bursting.
Whereas previous research into foams tended to look at the structures that are formed when different molecules assemble at the surface of bubbles, the British researchers instead looked at general surface properties.
According to lead researcher Dr Richard Campbell: “”It was only through our use of neutrons at a world-leading facility that it was possible to make this advance because only this measurement technique could tell us how the different additives arrange themselves at the liquid surface to provide foam film stability.”
In coming up with a solution, the researchers believe it is possible to develop a beer where the foam head, of the right proportion to begin with, lasts all the way to the bottom of the glass.
The new technology has been described in the journal Chemical Communications. The associated research paper is titled “New structural approach to rationalize the foam film stability of oppositely charged polyelectrolyte/surfactant mixtures.”