We investigated the effects of the odor of jasmine tea on autonomic nerve activity and mood states in a total of 24 healthy volunteers. We used the odor of jasmine tea at the lowest concentration that could be detected by each subject but that did not elicit any psychological effects. R-R intervals and the POMS test were measured before and after inhalation of the odors for 5 min. Both jasmine tea and lavender odors at perceived similar intensity caused significant decreases in heart rate and significant increases in spectral integrated values at high-frequency component in comparison with the control (P < 0.05). In the POMS tests, these odors produced calm and vigorous mood states. We also examined the effects of (R)-(-)-linalool, one of its major odor components, at the same concentration as in the tea, and (S)-(+)-linalool. Only (R)-(-)-linalool elicited a significant decrease in heart rate (P < 0.05) and an increase in high-frequency component in comparison with the controls, and produced calm and vigorous mood states. Thus, the low intensity of jasmine tea odor has sedative effects on both autonomic nerve activity and mood states, and (R)-(-)-linalool, one of its components, can mimic these effects.

The odorants in Chinese jasmine green tea scented with jasmine flowers (Jasminum sambac) were separated from the infusion by adsorption to Porapak Q resin. Among the 66 compounds identified by GC and GC/MS, linalool (floral), methyl anthranilate (grape-like), 4-hexanolide (sweet), 4-nonanolide (sweet), (E)-2-hexenyl hexanoate (green), and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (sweet) were extracted as potent odorants by an aroma extract dilution analysis and sensory analysis. The enantiomeric ratios of linalool in jasmine tea and Jasminum sambac were determined by a chiral analysis for the first time in this study: 81.6% ee and 100% ee for the (R)-(-)-configuration, respectively. The jasmine tea flavor could be closely duplicated by a model mixture containing these six compounds on the basis of a sensory analysis. The omission of methyl anthranilate and the replacement of (R)-(-)-linalool by (S)-(+)-linalool led to great changes in the odor of the model. These two compounds were determined to be the key odorants of the jasmine tea flavor.

The mechanism for the contribution of subthreshold aroma constituents to the overall jasmine tea odor impression was studied on the basis of a sensory evaluation. Binary model aqueous solutions containing the authentic odorants of a jasmine tea infusion, (E)-2-hexenyl hexanoate (I), (Z)-3-hexenol (II), and indole (III), were each prepared in a concentration below the odor threshold. Each solution had no aroma, but when 4-hexanolide replaced only 5% of each odorant, the odor intensity of each model solution was significantly strengthened. An astringent note and heavy note were recognized for each solution as the commonly perceived characteristics from the sensory evaluation. The concentration of 4-hexanolide added was also at the subthreshold level. The results suggest mutual interaction between odorants I, II, or III and 4-hexanolide. The effect on the overall odor sensation of a jasmine tea infusion by adding 4-hexanolide at a concentration below its odor threshold was also studied. In this case, the intensity of both the sweet and astringent notes was significantly strengthened in comparison with the odor impression of the original jasmine tea infusion. This phenomenon is considered to have been a synergistic effect between subthreshold odor compounds in the jasmine tea infusion. The results of this study clarify for the first time that the subthreshold aroma constituents play an important role in the characteristic flavor of a jasmine tea infusion.

No abstract

The potent odorants of the Sweetio pineapple (Ananas comosus ῌL.῍ Merr. var. Marian-gold (MG-)) were examined by comparing them with the regular pineapple (Ananas comosus ῌL.῍ Merr. var. Smooth Cayenne (F-,**)). The odorants in the pineapple extracts, which were pressed from fresh fruit, were separated by adsorption to Porapak Q resin. The total concentration of odorants in Sweetio pineapple extract was approximately twice that of regular pineapple, the upper, middle and lower parts containing higher odorants than their corresponding pars of the regular pineapple. .-Hydroxy-,,/-dimethyl-(,H)-furanone (furaneol) was found to be the most abundant compound in both pineapples. Sweetio pineapples contained higher proportions of methyl-(methylthio) propanoate, .-methoxy-,,/-dimethyl-(,H)-furanone (mesifurane), methyl hexanoate, .-hexanolide, methyl ,-methylbutanoate and ethyl hexanoate than regular pineapples. In addition to these compounds, aroma extract dilution analyses and empirical assessments of odor units revealed that methyl ,-methylbutanoate and ethyl ,-methylbutanoate appeared to be primarily responsible for the characteristic odor of Sweetio pineapples. The enantiomeric ratios of both esters were determined for the first time in this study. Ethyl ,-methylbutanoate was +**ῌ ee for the (S)-(̮)-configuration in both pineapples. Methyl ,-methylbutanoate in both regular and Sweetio pineapples were 33.*ῌ ee and 31..ῌ ee for the (S)-(̮)-configuration, respectively. Additive experiments using authentic racemic chemicals revealed that methyl ,-methylbutanoate and ethyl ,-methylbutanoate were the key odorants responsible for the "extending", "refreshing" and "fruity" notes of the extract, which, on the basis of sensory evaluation, were found to be significantly more intense in Sweetio pineapple extract compared to regular pineapple extract.