Abstract
There are flour-products which form the hollow body like chou and popover, but the mechanism of this formation has not been made clear. In order to understand what was taking place during baking such product, changes in the volume, the whole weight, the internal temperature and appearance of the product were investigated. The results were as follows.
1. The expansion proceeds with two stages on one-step cooking. The rate of expansion is slow at the first stage when small bubbles are formed at the bottom of the body. At the second stage this rate becomes faster. This period is important for the hollow body formation.
2. The expansion of the body reaches the maximum at a certain baking temperature. At lower temperatures, the expansion rate is slow at the second stage. At higher temperatures, the full expansion fails because the body loses the elasticity too early.
3. The correlation coefficient for the rate of expansion and that of weight loss is 0.98.
4. Even after the maximum volume is reached, visual changes continue inside the body. Inside the body, the raised gelatinous portion expands downward and it lines and partitions.
