Green Tea Research Today is a free monthly online journal that collates and summarizes the latest research about Green Tea, including details on benefits, antioxidants, weight loss, diet, side effects.

New constituents related to 3-methyl-2,4-nonanedione identified in green tea.

Naef R, Jaquier A, Velluz A, Maurer B

Firmenich SA, Corporate R&D Division, P.O. Box 239, CH-1211 Geneva 8, Switzerland. rfnaef@bluewin.ch

The volatile constituents of two exquisite green tea varieties, Kiyosawa tea from Japan and Long Jing tea from China, were investigated in order to identify new compounds responsible for the characteristic flavor of a green tea brew. The extracts were prepared by solid-phase extraction using Oasis-HLB-cartridges. Besides the common compounds of green tea chemistry, the already described compounds 3-methyl-2,4-nonanedione (1) and 3-hydroxy-3-methyl-2,4-nonanedione (2), products of degradation of furan fatty acids, as well as three new compounds related to compound 1 were identified. These were 1-methyl-2-oxopropyl hexanoate (3), 1-methyl-2-oxoheptyl acetate (4) and 2-butyl-4,5-dimethyl-3(2H)-furanone (5). Their syntheses and spectroscopic data are reported. Compound 2 increases the sweet, creamy aroma and the characteristic mouthfeel of a green tea flavor, compounds 3 and 4 contribute to its floral, juicy notes and compound 5 exhibits an interesting sweet, buttery flavor.

Published 22 November 2006 in J Agric Food Chem, 54(24): 9201-5.
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