Cooking corn porridge, is to let the fiber and starch particles in the high temperature water environment, physical and chemical decomposition. Let the natural state of the combination of tight corn particles, gradually become small particles, as well as more evenly distributed in the water starch, fiber. Oils and part of the heated hydrolyzed residual protein will be distributed in the top layer of the porridge, and then mixed with the top layer of starch particles and fibers.
In the upper layer of corn porridge, because of the temperature, the moisture is easy to radiate away, slowly will form a layer of oil and corn paste combined layer, it becomes a layer of dry corn paste skin. And slightly lower layer of starch, because of the high temperature water environment, water will still continue to run away, here the starch will disappear because of the water environment, and gradually and water to form a kind of hydrate state, probably similar to and water appeared to crystallize. This will change his physical form in the end and make him expand in volume. Here is where clumping occurs.
And the temperature at this time does not drop to the point where the water does not evaporate, so at this point, there will be a constant loss of water, while the volume continues to expand the change. Gradually, a water balance will be reached. This is when the lumps will be apparent. But after all, it is still starch, even after hydration, there is not too high hardness change, and there is still a lot of corn fibrous itself, it will become soft lumps. And the top layer, because there is the appearance of the oil skin, it becomes cracked in the form of the mechanism. After all, it is the first oil skin, and then after expansion and cracking formation.