When starch granules are heated in the presence of water, the granules eventually lose the double-helical crystalline structure and the Maltese cross. This process is known as gelatinization.
Starches of different botanical sources and genetic backgrounds display different gelatinization properties, including gelatinization temperature, enthalpy change and melting of amylose-lipid complex.
The gelatinization of starch is an irreversible process, and each starch has its own characteristic gelatinization temperature.
Water acts as a plasticizer during starch gelatinization, lowering the melting temperature of starch. This decreases the glass transition temperature of the non-crystalline regions of native starch and leads to melting of the crystalline parts as temperature is increased.
Starch gels are composites of swollen gelatinized granules embedded in a continuous amylose network.
When the gelatinized starch is continuously heated in excess water, the starch granules swell, develop viscosity and become a paste. This is known as pasting.
Starch gelatinization process
