Starch gelatinization

Starch gelatinization is a process that breaks down the intermolecular bonds of starch molecules in the presence of water and temperature and allows the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This penetration of water increases randomness in the general structure and decreases the number and the size of the crystalline region. The crystalline region does not allow water entry. When heat is applied this region will be diffused, so that the chains start to pull out from each other. The region is thus called amorphous.

This technique is also used in cooking to make white sauce or custard.