Rice bran oil (RBO) has been a popular choice of cooking oil in several Asian countries for decades, and the interest in RBO is fast growing in Western countries due to the high levels of hearty unsaturated fats and other components beneficial to health. Further knowledge of unsaturated fatty acid content and composition in rice lines will assist in improving the quality of rice bran processing by allowing robust extraction of rice bran for oil production. The studies focused on the RBO composition of rice lines with beneficial genotypes are scarce. Accordingly, we investigated the total bran lipid content and composition of three of the most abundant, healthy, unsaturated fatty acids that freely exist in RBO: oleic, linoleic, and α-linolenic acids in nine parental lines (two male sterile lines and seven male lines) and seven hybrid rice lines, by utilizing an efficacious organic extraction to collect RBO and by developing a user-friendly reverse-phase high-performance liquid chromatography (HPLC) methodology. Our results showed that the hybrid lines had the highest oil content (F ratio = 7.2017, p value = 0.0019), while the male lines had the highest levels of two of the three free unsaturated fatty acids analyzed (linoleic acid, mg and oleic acid, mg). Oil weight was negatively correlated with α-linolenic acid (r = -0.6535, p value <0.0001). All three free unsaturated fatty acids were positively correlated. Our samples' natural variation in lipid content suggests that some rice lines are more suitable for oil production.
Keywords: Oryza sativa L.; fatty acid composition; genetic variation; hybrid rice; lin; male sterile line; oleic acid; pollen donor; rice bran; rice bran oil; α-linolenic acid.