Each morning in his lab, Trevor Shen Kuan Ng, a graduate student in mechanical engineering, mixes a fresh batch of bread dough. After kneading it by machine, he uses devices called rheometers to stretch, pull, and twist two grams of it at a time. The rheometers then measure the effects of the manipulation.
The mechanical properties of dough, such as its elasticity and viscosity, vary greatly depending on factors like the ratio of ingredients, the moisture in the air, and the room temperature. Although there’s already an ample body of scientific literature devoted to dough, Ng believes that in many studies, not enough care was taken to reduce the degree of variability. That’s why he is working to develop accurate, reproducible techniques for measuring the properties of dough. He’ll use the results to learn more about dough’s microstructure–information that may help commercial bakers produce better bread.
Of particular interest to Ng is the mechanical behavior and microstructure of gluten. Gluten, which gives dough its elastic quality, is a type of protein compound known as a biomacromolecule, and it forms a tangled matrix that is the backbone of dough. “Despite the complex behavior of dough, when you isolate the gluten, you find that it is very close to a particular type of model system called critical gels,” Ng says. (A critical gel is neither a solid nor a liquid, but something in between.) The quality, shape, and distribution of gluten is known to be linked to a bread’s qualities, Ng says, “but exactly what qualities link to which property of bread making is a lot less well defined.”
Though his family is in the food business–his father runs a company that produces Chinese sauces in his native Hong Kong–Ng didn’t plan to end up there. “I began my time at MIT in the gas turbine lab working on high-speed compressors, which seemed far more like a typical MIT ‘rocket science’ project,” he says. But when Ng’s advisor, mechanical-engineering professor Gareth McKinley, dreamed up the dough project, working on it proved to be a welcome change: “It was just the right combination of experimental work, analysis, practical application, and, most important, creative thinking,” explains Ng.
After spending long days in the lab working with dough that never gets eaten, Ng likes to bake for fun at home. Though he prefers kneading his dough by hand to using a bread maker, he sees the value of employing technology to improve baked goods. “Baking is an art form,” he says. “It will be difficult to replicate the techniques of a professional baker through machines. However, if we can at least understand the underlying physics of the process, it might lead us to cheaper or better breads.”