1. Introduction
Rough rice can be separated into husk and brown rice (BR)
through a threshing process, and BR can be further separated into
starchy endosperm (about 92%), embryo (about 2%), and bran
(about 6%). Polished rice, also called white rice (WR), is obtained
by removing the bran. Although minor differences in the degree
of milling exist, polished rice is essentially considered endosperm
only.
Along with maize and wheat, rice is among the most widely
consumed grains in the world. Rice also provides 20% of the world
dietary energy supply, which is a higher portion than those of
wheat and maize (19% and 5%, respectively). In contrast with maize