The Microstructure of Polished, Milled and Air-classified Rice and Rice Bran

Abstract

The microstructure of polished rice, its milled and air classified fractions was observed under a scanning electron microscope. The cells of rice endosperm, showing long rectangular column shape, distributed radially from center to outer layer. In the cells, many compound starch granules in polygonal shape plugged up. By immersion in water, NaCl or alkaline solution, cleavage and degra dation of the structure were accelerated. Milling and air-classification of polished rice were examined to get a protein rich fraction. Such a fraction(total N:9.4%)was obtained from the flour (total N:7.4%). The sonic treatment of rice bran in the presence of n-hexane and successive milling and air-classification gave a relatively promissing result to get protein rich flour.