3. Conclusion
The levels and compositions of lipid substances in rice seed were affected by genotype and DAF. Although there was a difference in the changes of the amount of lipid substances, similar trends were observed in two cultivars. The lipid extract levels increased significantly during an early stage of development in the two rice cultivars. The major fatty acids of two cultivars examined were palmitic acid (2), oleic acid (4), and linoleic acid (6). The proportion of α-linolenic acid (7) decreased significantly whereas that of oleic acid (4) increased. The γ-oryzanol (9–12) levels increased in the two cultivars during the development, but with differences in the γ-oryzanol isomer (9–12) composition. The major steryl ferulates in Ilpum were cycloartenyl ferulate (9) and 24-methylene cycloartanyl ferulate (10), whereas the major steryl ferulates in Dasan were 24-methylene cycloartanyl ferulate (10) and campesteryl ferulate (11) at maturity. The major policosanols in the two cultivars were octacosanol (15) and triacontanol (16), even though there are differences in the composition between the two cultivars during rice development. The total policosanol level decreased drastically during the early stage in the two rice cultivars. Tocopherol (17–20) levels significantly decreased, while a slight increase in tocotrienol (21–24) levels during rice development was observed. The predominant tocol in Ilpum was α-tocopherol (17) thorough development, but, in Dasan, γ-tocotrienol (23) at maturity.