Changes in lipid substances in rice during grain development.

Lipid substances, such as fatty acids, γ-oryzanol, policosanols, and tocol (tocopherol+tocotrienol), were investigated in two rice cultivars, Ilpum and Dasan, during rice development. In both cultivars, the lipid extract level decreased steadily after it reached its maximum level. Additionally, there were differences in the fatty acid composition, depending on the rice developmental stage, between the two cultivars. The γ-oryzanol level increased during rice development, and there were differences in the composition of γ-oryzanol between the two cultivars. The levels of policosanols drastically decreased during the early stage of rice development in the two cultivars. The total tocol level showed a downward trend during rice development. The predominant tocol isomer in Ilpum was α-tocopherol during rice development. In Dasan, the predominant tocol isomer was α-tocopherol at the early stage, but γ-tocotrienol at the later stage. This study provided information on the levels and composition of lipid substances, such as fatty acids, γ-oryzanol, policosanols, and tocol during rice development.