Characterization and quantification of γ-oryzanol in Korean rice landraces

Rice grain contains several functional compounds. Among these, γ-oryzanol is one of the most important owing to its biological role in human physiology. This study was conducted to determine the γ-oryzanol in Korean rice landraces, and classify them based on grain γ-oryzanol composition and contents. Ten fractions of γ-oryzanol were identified in the tested landraces with total γ-oryzanol contents ranging from 0.69 to 51.40 mg/100 g. Among individual components, 24-ethylene cycloartanyl ferulate, cycloartenyl ferulate, campesteryl ferulate and sitosteryl ferulate contributed to ∼90% of total γ-oryzanol with the highest values in landraces Paldado, Jaeraeryukdo, Ichun7ilchal and Dudo respectively, while △7-sitostenyl ferulate constituted only ∼0.30% of total γ-oryzanol. Korean rice landraces were classified in six groups based on oryzanol composition. Group 1 was glutinous rice with high oryzanol content (19.44 mg/100 g hulled rice), while group 2 had the lowest oryzanol content (9.57 mg/100 g hulled rice) with late maturation. Colored rice landraces included in group 5 had high oryzanol contents (17.02 mg/100 g hulled rice). Campesteryl ferulate contents were higher in non-glutinous rice. γ-oryzanol composition pattern can serve as basis for classification of Korean rice landraces, and for use in the breeding programs to develop γ-oryzanol rich rice cultivars.