After the starch is pasted, the hydrogen bond between the crystalline and amorphous molecules is broken, and the starch molecules are swollen and dispersed in the water to form a colloidal solution, which leads to the easy access of α-amylase to the inside of the starch molecules for hydrolysis, and makes the pregelatinized starch with higher a-chemical degree.
Aging starch is raw starch in the pasting process, has been dissolved and swollen starch molecules re-arrangement and combination, the formation of a material similar to the structure of natural starch, linear starch molecules re-arrangement and through the hydrogen bonding to form an insoluble precipitate, the starch in water solubility decreases, resulting in aging starch α - chemical degree is lower.