The difference between starch gelatinization and starch aging is different principle. Principle of starch gelatinization: at room temperature, the amorphous part of starch granule is slightly swollen in the water environment, if the starch is stirred, it will show the suspension state, and if the starch is static, it will return to the precipitation state. If the starch is cooled and dried at this time, the starch granules can be restored and the birefringence phenomenon remains unchanged. When a dilute starch solution is cooled, the linear molecules rearrange and form an insoluble precipitate through hydrogen bonding. When a concentrated starch paste is cooled, the starch molecules rearrange faster in a limited area, the linear molecules are joined and the solubility decreases. The whole process of starch solubility reduction is called aging.