Di#erences in the aromas of steamed green teas are due to the cultivars, the climate and the production process. We compare the volatile compounds found in steamed green tea of the same cultivar (cv. Yabukita (Camellia sinensis var. sinensis)) but produced in di#erent places (Saitama, Shizuoka, Mie, Nara, Kyoto, Saga and Miyazaki prefectures). A total of 1/ volatile compounds were identified by GC and GC/MS. The results showed observed di#erences in the quantities of these compounds. Principal component analysis (PCA) was performed for the GC data to investigate the relationship between green teas from di#erent places. Each green tea was found to contain certain characteristic compounds.

We evaluated the volatile compounds of Japanese green tea using GC/O with the original aroma simultaneously input to the sni$ng port (OASIS) method in order to determine the relationship between the volatile compounds and the green tea aroma. Application of OASIS to the volatile fractions of Japanese green tea infusions revealed ++ odor-active peaks. Those of cis-+,/-Octadien---one, .-mercapto-.-methyl-,-pentanone, --methylnonane-,,.-dione, geraniol, decanal and cis---hexenol emphasized the green note of the tea. ,-Acetylpyrrole, ,-ethyl--,/-dimethylpyrazine and ,-acetyl--,/-dimethylpyrazine emphasized the roast note. Indole strengthened the overall green tea odor. b-Ionone emphasized the sweet note in the green tea. Of these odorants, ,-acetyl--,/-dimethylpyrazine was identified for the first time as a volatile compound in tea.

Recent studies of natural aromas have focused on only the lowest odor threshold compounds. In this study, we evaluated the volatile compounds of Japanese green tea, comparing the original aroma simultaneously input to the sniffing port method (OASIS) with the aroma extract dilution analysis method (AEDA). Geraniol, indole and linalool were classified in the low odor threshold by AEDA. Using OASIS, geraniol showed enhancement of the green character and indole showed strengthening the overall green tea odor, but linalool gave the same result as AEDA. On the other hand cis-3-hexenol, decanal and ␤-ionone were classified in the high odor threshold by AEDA, OASIS showed enhancement of the green, tea-leafy, and sweet characters respectively. We added these compounds to a Japanese green tea infusion and evaluated it. The results showed great similarity to the OASIS results. In conclusion, OASIS is an effective technique by which to evaluate mixtures of volatile compounds with original aromas.

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