Evaluation of Japanese Green Tea Extract Using GC/O with Original Aroma Simultaneously Input to the Sniffing Port Method (OASIS)

Abstract

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 β-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.