Achieving the perfect al dente texture for a pasta noodle can be tough. Noodles can take different times to fully cook and different recipes call for different amounts of salt to be added. Sometimes noodles will stick to each other or the saucepan.
Scientists examined how pasta swells, softens and becomes sticky as it takes up water. They combined measurements of pasta parameters like expansion, bending rigidity and water content to solve a variety of equations to form a theoretical model for the swelling dynamics of starch materials.
Scientists said exploring the properties of noodles was a straightforward pivot from the lab’s main work of studying the fluid structure interaction of very flexible and deformable fibers, hairs and elastic structures.
The idea gained traction and students and postdocs started working on it at home and in the lab. Scientists observed how the noodles come together when lifted from a plate by a fork. This provided them with a grounding of how water-driven hygroscopic swelling affects pasta’s texture.
The relative rate of the noodle’s increase in girth exceeded the rate of lengthening by a ratio of 3.5 to 1 until it reached the firm texture of al dente, as pasta cooked.
The liquid surface energy creates a meniscus that sticks noodles to one another. It balanced the elastic resistance from bending the noodles and aided by adhesion energy from the surface tension of the liquid. The degree to which a noodle was cooked was directly related to the length of the portion that adhered to its neighbours.