Optical Isomers and Odor Thresholds of Volatile Constituents in Citrus sudachi

The enantioselective analysis of the volatile components in Citrus sudachi peel oils was achieved using an enantioselective capillary gas chromatography (enantio-cGC) with α- and β-cyclodextrin columns. The two isomers of linalool and α-pinene showed highly significant differences in both odor detection thresholds and odor qualities. The other investigated compounds also differed either in the odor intensities or in the odor qualities. According to limited odor units (ratio of the concentration of each component to the odor threshold), (3S)-(+)-linalool, (3R)-(—)-linalool, octanal, (4R)-(+)-limonene, (1R,5R)-(+)-α-pinene, p-cymene, γ-terpinene, myrcene, 1,8-cineole, (3R)-(+)-citronellal, decanal, α-phellandrene and dodecanal contributed to the Citrus sudachi aroma.