The flavor-enhancing effects of the volatile constituents in celery were investigated. The test samples were prepared by adding celery fractions to chicken broth at a concentration that distinct odors of them were not detected, and the samples were sensorially evaluated for the perceived intensities of 8 terms such as "thick," "impactful," "mild," "lasting," "satisfied," "complex," "refined," and "clarified," which are considered to be the elements of the complex flavor and for 3 terms such as "sweet," "salty," and "umami" taste. A comparison of effects between the volatile and nonvolatile fractions of celery revealed that the volatile compounds in celery enhanced the complex flavor of chicken broth more than the nonvolatile compounds. Among the characteristic odorants of celery, three phthalides, namely, sedanenolide, 3-n-butylphthalide, and sedanolide, were shown to contribute to the complex flavor of chicken broth, and sedanenolide was most effective. The three phthalides enhanced perceived intensities of "umami" and "sweet" despite their no taste properties in addition to the complex flavor.

Symplocarpus renifolius (Asian skunk cabbage) is a perennial herb of the Araceae family. As its common name implies, this plant produces a strong garliclike irritant odor with a rotten note when the plant parts are crushed. To elucidate the odor characteristics, the volatile compounds released from crushed plant parts (rhizome, petioles, and leaf blades) of S. renifolius were identified by a dynamic headspace method. Fifteen sulfur compounds were identified as odoractive compounds by gas chromatography−mass spectrometry−olfactometry (GC−MS−O). The sulfur compounds may be responsible for the strong odor emitted by crushed skunk cabbage. Many of the compounds lack a carbon−carbon bond, and all of the carbon atoms are connected to sulfur. This is regarded as the characteristic structure of the sulfur compounds released from the damaged plant parts of the skunk cabbage. Nine of the sulfur compounds were detected in all three of the plant parts analyzed in this study: hydrogen sulfide, methanethiol, 1-hexanethiol, methyl dithioformate, 2,4dithiapentane, dimethyl trisulfide, methional, 2,3,5-trithiahexane, and tris(methylthio)methane. Methyl dithioformate and methylthiomethyl dithioformate were identified for the first time as natural products.