New Constituents Related to 3-Methyl-2,4-nonanedione Identified in Green Tea

Regula Naef,† Alaini Jaquier,* Alain Velluz, and Bruno Maurer
Firmenich SA, Corporate R&D Division, P.O. Box 239, CH-1211 Geneva 8, Switzerland
J. Agric. Food Chem., 2006, 54 (24), pp 9201–9205
DOI: 10.1021/jf061738o
Publication Date (Web): November 4, 2006
Copyright © 2006 American Chemical Society
†

 Present address:  Achermattstrasse 4, CH-6423 Seewen, Switzerland. E-mail:  rfnaef@bluewin.ch.

,
*

 To whom correspondence should be addressed. Phone:  +41 22 780 34 70. Fax:  +41 22 780 33 34. E-mail:  alain.jaquier@firmenich.com.

Abstract

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.

Keywords: Green tea; Camellia sinensis; 3-methyl-2,4-nonanedione; 3-hydroxy-3-methyl-2,4-nonanedione; 1-methyl-2-oxopropyl hexanoate; 1-methyl-2-oxoheptyl acetate; 2-butyl-4,5-dimethyl-3(2H)-furanone; new constituents

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History

  • Published In Issue November 29, 2006
  • Received for review June 21, 2006. Revised manuscript received August 23, 2006. Accepted August 25, 2006.

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