title: New constituents related to 3-methyl-2,4-nonanedione identified in green tea.
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.
authors.affiliation: Firmenich SA, Corporate R&D Division, P.O. Box 239, CH-1211 Geneva 8, Switzerland. rfnaef@bluewin.ch
authors.forename: Regula
authors.initials: R
authors.lastname: Naef
authors.forename: Alaini
authors.initials: A
authors.lastname: Jaquier
authors.forename: Alain
authors.initials: A
authors.lastname: Velluz
authors.forename: Bruno
authors.initials: B
authors.lastname: Maurer
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D003931:Diacetyl / Q000031:analogs & derivatives* / Q000737:chemistry; D006801:Humans; D013058:Mass Spectrometry; D009812:Odorants; D013662:Tea / Q000737:chemistry*
chemical_list: D000473:Alkanes; D013662:Tea; C475572:3-methyl-2,4-nonanedione; D003931:Diacetyl