Abstract: A method to provide processed brown rice, in which the content of free ferulic acid that contributes to the amelioration of dementia, can be increased. High water pressure-treated processed brown rice characterized by being obtained by applying hydrostatic pressure of 100 MPa to 600 MPa to brown rice in water at 0 degrees C. to 35 degrees C. to thereby increase the content of free ferulic acid in the brown rice, and drying the brown rice immediately after the application of the hydrostatic pressure. Fermented food such as bread, sake or sake lees that are manufactured by using the processed brown rice as raw material, characterized in that the content of free ferulic acid in the fermented food has been increased by fermenting the processed brown rice with using yeast or by pregelatinizing the processed brown rice and then fermenting the same with using yeast.