Comparative Composition of Brown Rice Lipids (Lipid Fractions) of Indica and Japonica Rices.

The brown rice lipids were analyzed from three japonica and two indica rices. They had substantially no difference in the ratio of NL, GL, and PL, the C16/C18 (16:0/the sum of 18:0, 18:1, 18:2, and 18:3) ratio in PL classes, and in the order of unsaturated index in each glycerolipid class among the five varieties. However, the chemical compositions of glyceroglycolipids and cerebroside were different in indica and japonica rices. The contents of 18:3 of MGDG and DGDG were higher in japonica than indica rices, but those of 16:0 were reversed. The ratio of C14-20/C21-26 of the hydroxy fatty acids in cerebroside was 1.18 in japonica and 0.62 in indica rices. Furthermore, the ratio of the trihydroxy sphingoid bases to dihydroxy ones showed a great difference between the subspecies. Unsaturated fatty acid contents in the TG and PL classes were largely different from each other among japonica rices harvested in separate districts.