Characteristic Chemical Components and Aroma-active Compounds of the Essential Oils from Ranunculus nipponicus var. submersus Used in Japanese Traditional Food.

Ranunculus nipponicus var. submersus is an aquatic macrophyte; it is known as a wild edible plant in Japan for a long time. In this study, the essential oils from the fresh and dried aerial parts of R. nipponicus var. submersus were extracted by hydrodistillation and analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Moreover, important aroma-active compounds were also detected in the oil using GC-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). Thus, 98 compounds (accounting for 93.86%) of the oil were identified. The major compounds in fresh plant oil were phytol (41.94%), heptadecane (5.92%), and geranyl propionate (5.76%), while those of. Dried plant oil were β-ionone (23.54%), 2-hexenal (8.75%), and dihydrobovolide (4.81%). The fresh and dried oils had the green-floral and citrus-floral odor, respectively. The GC-O and AEDA results show that phenylacetaldehyde (green, floral odor, FD-factor = 8) and β-ionone (violet-floral odor, FD-factor = 8) were the most characteristic odor compounds of the fresh oils. β-Cyclocitral (citrus odor, FD-factor = 64) and β-ionone (violet-floral odor, FD-factor = 64) were the most characteristic odor compounds of the dried oil. These compounds are thought to contribute to the flavor of R. nipponicus var. submersus.