In order to improve the properties of starch and expand its application, physical, chemical or enzymatic treatment is used to introduce new functional groups into starch molecules or change the size of starch molecules and the properties of starch particles, so as to change the natural properties of starch (e.g. Gelatinization temperature, thermal viscosity and its stability, freezing and thawing stability, gel force, film forming, transparency, etc.) make it more suitable for certain application requirements. This secondary processing, change the properties of starch collectively known as modified starch.