Constitutive Properties of Soft Aerated Food Materials

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Many foods and drinks need bubbles to create unique textures and flavours. If you're not convinced of this, try a taste test with a freshly-opened and a day-old can of cola. But, in addition, bubbly foods and food foams display some really interesting properties that we don't yet fully understand. Over the next five years, I want to examine how the properties of these fragile food materials are affected by the bubbles they contain. In the first objective we will examine how ingredients affect the physical properties of bubbly foods with both low and high concentrations of bubbles. Real food examples would be dough (low) and meringues (high). Because bubble distributions in soft materials evolve rapidly, we will also study bubble dynamics. In fact, bubble sizes change so rapidly in soft solids such as dough that we will need to use one of our planet's most intense beams of light (the Canadian Light Source) to successfully study these changes. One outcome from the research is that by understanding the forces driving bubble size changes, we can create better aerated foods as a result of their stabilization. In the second objective we will examine how the protein matrix that supports the bubbles in many aerated foods is affected by squeezing the protein molecules with pressures up to 8000 atmospheres. This approach is not just an academic exercise because high pressure processing is increasingly used to ensure that our food is safe as well as fresh. From these pressurization studies, we expect to derive fundamental thermodynamic properties for dairy foaming proteins utilizing precise measurements of the physical properties of the protein solutions. An expected outcome is that these thermodynamic properties will allow us to better control high pressure processing to produce additive-free ingredients for aerated foods. Learning more about the nature of aerated food materials will benefit the biological sciences by establishing simplifying principles that can be applied to get a better understanding of the properties of other soft biological materials. Canadians will benefit because a better understanding of how to process bubbles and food materials will allow food manufacturers to create high quality foods with more healthy ingredients without impacting the original taste.