Abstract
Two varieties of brown rice used for sake brewing were milled to yields of 70% by controlling the supply brown rice, surface roughness and rotational frequency of the roll in a horizontal and abrasive type rice-milling test machine. The average and variance of two shape indices were calculated from size measurements in three dimensions for fifty milled grains under different milling conditions and analyzed statistically. From investigations on the effect of milling condition on the decrease in three dimensions of brown rice, as well as the mechanical interactions between individual rice grains and the roll during rice milling, a dimensionless equation was derived for estimating the shape of milled rice from the physical variables associated with specific milling conditions.
