Abstract
Doughnut cracking during deep frying was confirmed to occur by a mechanism involving three types of cracks. One type was on the top of the doughnut, the second was on the outside, and the third was on the inside of the doughnut ring.
We calculated the change in cracking pressure during deep frying from measurements of the tensile strength, average curvature, and thickness of the crust layer of the doughnut. Changes in the internal pressure were obtained from measurements of the cubic dilatation and bulk modulus.
Each type of crack could be explained by the relationship between the internal pressure of the dough and the cracking pressure of the crust during deep frying. When the internal pressure exceeded the cracking pressure, cracks occurred.
