Whether you prefer your spaghetti al dente or deliciously tender, it is not always easy to achieve perfection at home. Many of us have experienced seeing our pasta turn into a beige mush, especially when it comes to gluten-free alternatives.
So how much water and salt should you really use and how long should you cook pasta for optimal results? And above all, how can you adapt your cooking method when using gluten-free pasta? A recent study that my colleagues and I conducted, which will be published in March 2026 in the journal Food Hydrocolloids, provides answers by revealing the physics of the cooking process.
Turning to the Diamond Light Source, the UK’s national synchrotron (a circular particle accelerator), we studied X-ray scattering on pastes, to reveal their internal structure. We then went to the ISIS laboratory and the Laue-Langevin Institute, two research centers located respectively in the United Kingdom (south-east of England) and in France (in Grenoble), to analyze using neutrons (which, with protons, make up the atomic nucleus) the microstructure of classic and gluten-free spaghetti subjected to different cooking conditions.
The study shows how the hidden structure of pasta changes during cooking and why gluten-free versions behave so differently. This device allowed us to examine the structure of starch and gluten in spaghetti at very fine scales, ranging from several tens of times the radius of an atom to several thousand times. We were thus able to compare the transformations that take place in classic and gluten-free pasta under various cooking conditions – for example, when they are overcooked or cooked without salt.
Our experiments allowed us to “see” the different components of the pasta separately. By mixing normal water and “heavy water” (which contains an isotope called deuterium), we could make either gluten or starch invisible to the neutron beam. In this way, we were able to effectively isolate each structure in turn and understand the respective roles of starch and gluten during cooking.
The role of gluten and salt
Our study shows that, in classic pasta, gluten acts as a strong framework that holds the starch granules in place even during boiling, giving the pasta its firmness and slow digestion. In gluten-free pasta, on the other hand, starch granules swell and collapse more easily, which explains their pasty texture and faster degradation when this type of pasta is cooked under suboptimal conditions.
We also studied the effect of the salt contained in the cooking water on the structure of the pasta. We found that salt not only improves their taste: it strongly influences the microstructure of spaghetti. When conventional pasta is boiled in salted water, the gluten retains its structure and the starch granules are less altered by the cooking process.
So how much salt should you add to preserve the microscopic structure of the pasta? Our study found that 7 grams of salt per liter of water is ideal, with more water needed for larger portions of pasta. The ideal cooking time is ten minutes for classic pasta and eleven minutes for gluten-free pasta. Conversely, when the salt concentration was doubled, the internal order degraded more quickly and the structure of starch granules was significantly altered by cooking.
For gluten-free doughs, the conclusions were again different due to the lack of the protection offered by gluten. Even small amounts of salt could not compensate for this absence. Artificial compounds made from processed starches, used by manufacturers to replace gluten, were degrading quickly. The most extreme example of this degradation occurred when gluten-free spaghetti was cooked too long – for example thirteen minutes instead of eleven – and in very salty water.
The main conclusion is therefore that gluten-free doughs are structurally more fragile and less tolerant to prolonged cooking or poor salt proportions.
Improving gluten-free alternatives
Understanding the structure of doughs at such tiny scales, invisible even under a microscope, will help design better gluten-free foods. The objective is in particular to create gluten-free alternatives that are more resistant to poor cooking conditions and whose texture is closer to that of classic spaghetti.
Classic wheat pasta has a low glycemic index because gluten slows the breakdown of starch granules during digestion. Gluten-free pastas, made from rice and corn flours, often lack this structure, leading to a faster release of sugars. Using neutron scattering, food scientists can now identify which ingredients and cooking conditions best replicate the structure of gluten.
It is also an illustration of how cutting-edge experimental tools, mainly used for fundamental research, are transforming food research today. Neutron scattering has played a critical role in understanding magnetic materials, batteries, polymers and proteins. It now also makes it possible to explain the behavior of our everyday foods on a microscopic scale.
