Leavened bread, for instance has a porous structure that de- pends on a reinforcing gluten protein network. When the gluten network was disrupted by protein digestion in the gastric phase,
a starch slurry resulted, which was immediately and almost totally accessible to amylase digestion. Similarly, many of the biscuits and breakfast cereals consisted of expanded, porous starch matrices, high in soluble sugar. They rapidly hydrated and collapsed quickly during digestion, providing a high proportion of RAC.
Mashed potato, although not a cereal, is included as an example of a material that contains very thin cell walls and is disperse, so it has neither primary nor secondary structure, and is predominantly RAC.