Abstract
Six types of pulverized rice were prepared by ultracentrifuge cryomilling. In this method, the sample being pulverized is immersed in liquid nitrogen. The moisture content and protein content of pulverized rice obtained were determined, and their characteristics were compared with those of rice flours pulverized with three types of mill (disk mill, hammer mill, and jet mill) and a purified non-waxy rice starch. The particle size distributions of rice pulverized by ultracentrifuge cryomilling showed two peaks at 14.3–17.8 μm and 52.1–92.1 μm. The most finely pulverized rice showed a major peak at 17 μm. The pulverized rice particles (average particle size of 40 μm) were composed of spherical shapes. Rice flour pulverized to a micro-scale point (average particle size of 6.5 μm) was characterized by the enhancement of whiteness, which is one of the most important indices for bulk flours.
