Identification of volatile compounds which enhance odor notes in Japanese green tea using the OASIS (original aroma simultaneously input to the sniffing port) method

Abstract

We evaluated the volatile compounds of Japanese green tea using GC/O with the original aroma simultaneously input to the sniffing 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 11 odor-active peaks. Those of cis-1,5-Octadien-3-one, 4-mercapto-4-methyl-2-pentanone, 3-methylnonane-2,4-dione, geraniol, decanal and cis-3-hexenol emphasized the green note of the tea. 2-Acetylpyrrole, 2-ethyl-3,5-dimethylpyrazine and 2-acetyl-3,5-dimethylpyrazine emphasized the roast note. Indole strengthened the overall green tea odor. β-Ionone emphasized the sweet note in the green tea. Of these odorants, 2-acetyl-3,5-dimethylpyrazine was identified for the first time as a volatile compound in tea.