Samples and sample preparation
White (9311), red (SB7), and black (Yunanheixiannuo) rice grains
(Oryza Sativa L.) were grown and harvested in Hangzhou China, in
2011. After sun drying to a moisture content of 10e11%, grains were
stored under darkness at 4 C. Prior to analysis, grains were
dehusked on a Satake Rice Machine (Satake Co., Tokyo, Japan). Any
broken kernel was removed. The embryos were separated manually
from brown rice (w0, about 50 g) and weighed (w1). All separations
were done on an ice-bath. The degermed rice grains were polished
on a Satake mill (Satake Corp., Tokyo, Japan) to collect the bran and
endosperm. The weight of endosperm was marked as w2. The polished
rice grain and whole grain were milled and passed through a
100 mesh sieve on a Cyclone sample mill (UDY Corporation, Fort
Collins, CO). All the samples are shown in Fig. 1. The percentages of
embryo, bran, and endosperm were calculated as follows:
embryo ð%Þ ¼ w1=w0 100;