PROBLEM TO BE SOLVED: To eliminate the need for power used for roll milling by carrying out treatment for significantly reducing the hardness of rice, and to provide fine rice powder with good quality even when the rice is ground only with a jet mill.SOLUTION: The method for producing the rice powder includes: a preprocessing step 5 of creating a number of fine cracks on the surface of an uncooked rice grain a water-adding step 12 of increasing the water content of the rice grain having the fine cracks formed on the surface thereof and a grinding step 19 of grinding, with the jet mill, the rice grain having absorbed water. That is, when the water is added after the fine cracks are formed on the surface of the rice grain, the swelling of a compound starch grain proceeds remarkably faster than in the case of water being absorbed gradually through a germ. The rapid swelling increases the amount of strain in the structure of a cell wall, making it easy to break the strong structure of the cell wall and significantly reducing the hardness of the rice. In the case of grinding, by virtue of the significant reduction in the hardness of the rice, the structure of the cell wall is easily broken and even a starch grain is finely ground.COPYRIGHT: (C)2012,JPO&INPIT【課題】米の硬度を著しく低下させる処理を行うことで、ロール製粉用の動力が不要であり、かつ、気流粉砕機のみで粉砕した場合であっても、微細で良質な米粉を提供する。【解決手段】原料米の表面に微細な亀裂を多数生じさせる前処理工程5と、表面に微細な亀裂を生じさせた米粒に水分を増加させる加水工程12と、加水後の米粒を気流粉砕機にて粉砕する粉砕工程19とを含む。すなわち、微細な亀裂を形成した後に加水を行うと、胚芽部を介して徐徐に吸水するよりも、デンプン複粒への膨潤の進行が著しく早まることになる。この急速な膨潤により細胞壁組織のひずみ量が増加し、強固な細胞壁組織が破壊されやすくなり、米の硬度が著しく低下する。粉砕時にあっては、米の硬度の著しい低下により、細胞壁組織が簡単に破壊され、デンプン単粒まで細かく破砕される【選択図】図1
