[Problem] To provide a method for modifying water retention during moist heating of a starch processed product. [Solution] Modification processing is performed for maintaining the water balance in processed grain, wherein a raw material to be modified is added in the amount of 0.1 to 1.0 wt%, in konjac mannan powder equivalent, to an alkali component that is a thickening component and to a soluble dispersant, the konjac mannan powder evenly permeates the proteins in the raw material of processed grain, and the konjac mannan component links with the protein component contained in the raw material to form a meshed water retention structure. Accordingly, the amount of water retained in the modified processed product is increased, and bulk is also increased. In addition, there is no movement of water after frozen storage, and restoration is achieved by the water balance during cooking by heat restoration.
