citral, beta-sesquiphellandrene, zingeberene, and gingerols/shogaols
Ginger
Zingiber officinale (Zingiberaceae)
Ginger is a rain forest monocot about a metre high, with long, narrow
leaves and spicate flowers. It has been grown in India and China since
Antiquity. Seeds have never been found, ginger propagates through buddings
from its knotty rhizome. Today India, Malaya, Taiwan and Fiji are the
main exporters.
The fresh ginger rhizome is a versatile ingredient of the far eastern
cuisine, and is now commonly used in most of the world. Its flavour is
lemony-balsamic and its taste is medium hot.
The lemony character of fresh ginger is due to citral.
Major components of the essential oil are the sesquiterpenes beta-sesquiphellandrene
and zingiberene. The 'sharp' constituents, causing the burning sensation
on the mucous membranes, are substituted phenols (gingerols/shogaols)
[6].
In the ginger family we also find cardamom,
Elettaria cardamomum, galanga,
Alpinia galanga, and turmeric,
Curcuma longa.
nootkatone
1-p-menthene-8-thiol
-limonene.gif)
(+)-limonene
Grapefruit
Citrus paradisi (Rutaceae)
Grapefruit is believed to be a crossing of pomelo, C. maxima,
and bitter orange, C. aurantium ssp. amara.
The special grapefruit aroma is characterized by its 'bitter-green-woody'
nuance. As with most citrus fruits, grapefruit peel oil is dominated by
(+)-limonene, but the particular grapefruit character is due to the sesquiterpene
ketone nootkatone. The distinctive topnote of grapefruit juice is owing
to trace amounts of 1-p-menthene-8-thiol, one of the most powerful odorants
known (odour detection threshold in water ~ 0.0001 ppb) [3]. New, milder,
pink or red varieties of the grapefruit have become very popular.
about new, artificial grapefruit odorants
Recently, the grapefruit nuance has become popular in perfumery as a variation
of the classical Eau de Cologne theme. Nootkatone, however, is rather
expensive, and several compounds of somewhat similar character have been
developed. A few examples are shown on the right. Methyl Pamplemousse
® is used at 8.5 % in the perfume Good Life (Davidoff 1998) [43].
Dimethyl Octenone, or 4,7-dimethyl-6-octen-3-one, may give original and
natural grapefruit effects in certain modern accords, according to Givaudan.
The grapefruit note may even be found in some amides.
N-methyl-N-phenyl-2-methylbutanamide or Gardamide ® (Quest) is described
as having "a zesty grapefruit-citrus heart note with aspects of crisp
rhubarb."
Methyl Pample-mousse ®
Amarocit ®
Dimethyl
Octenone
Gardamide ®
guaiol, bulnesol and guaiyl acetate
Guajacum officinale (Bulnesia sarmienti) (Zygophyllaceae) 'Lignum Vitae'
The guaiac tree is a small, slowly growing tree from northern South America with opposite, leathery leaves and bluish or pink flowers. The wood is some of the hardest and densest known. It is used for special objects where strength and low friction is required.
The wood is soaked with a fragrant resin. By steam distillation of saw-dust and wood remnants the so-called guaiac wood oil is obtained, having a mild, 'precious-woody' odour. Two sesquiterpene alcohols, guaiol and bulnesol, make up about 85 % of the oil, crystallizing at room temperature [6]. Guaiyl acetate is made from guaiac wood oil. It is an expensive fragrance chemical having an elegant, mild, Tea-Rose-like odour. It is used as a fixative in luxury perfumes.
major volatiles from hawthorn flowers
Crataegus monogyna (Rosaceae) Single-seed hawthorn
Specialists are often needed to determine the identity of hawthorn species. Hawthorns cross-breed easily, forming a multitude of hybrids, and speciation seems to continue. Hawthorn thrives in brushwood and pastures. In southern Scandinavia it blooms in May. The berries are eaten by birds during the winter, whereby the seeds are spread.
The flowers are sweetly scented, but with a nauseous tone due to trimethylamine, also known from herring brine, and 3-pyridinecarboxaldehyde. Other odor determining volatiles are benzaldehyde, 4-methoxybenzaldehyde (anisaldehyde) and methyl 4-methoxybenzoate (methyl anisate) [22].
Etymology: Gr. krataigos, the name of a hawthorn species. In Germany hawthorn is called Weissdorn, in France aubépine.
filbertone and 1,3-
dimethoxybenzene
Corylus avellana (Betulaceae) Common hazel
Corylus maxima (Betulaceae) Filbert
There are some ten species of hazels, all from the northern hemisphere. Common hazel is found in most of Europe. In the western Pyrenees, for example, it forms a major part of the natural forest vegetation together with beech and box.
Hazel is flowering in early spring long before foliation. The light male catkins are hanging from the leafless branches. The tiny female flowers, unknown to most people, have their ruby red stigmas protrude from what looks like ordinary buds (enlarged 6 x in the photo).
Two character impact compounds from the aroma of hazelnuts should be mentioned, the so-called filbertone,
or 5-methyl-2-hepten-4-one, and resorcinol dimethyl ether, or 1,3-dimethoxybenzene, the latter being especially evident from old hazelnuts. It has also been detected in Port Wine [153] [154] [155].
On roasting, hazelnuts get a delicate crisp texture and a rich aroma from specific browning reactions, generating small amounts of pyrazines, pyrroles, etc. Roasted hazelnuts are used on a very large scale in chocolate bars, nut truffles, etc. Turkey is the world’s largest producer of hazelnuts, contributing approximately 70% of the global production [152].
Etymology: Lat. Corulus, the old Latin name for hazel; Lat. avellana, from Avella or Avella Vecchia, a commercial centre east of Napoli, formerly famous for its hazelnut trade.
branched esters, and the sesquiterpene lactone aromatin
Helenium aromaticum (Cephalophora aromatica) (Compositae) Manzanilla de la Montaña, 'Pineapples'
The Heleniums are all American. Helenium aromaticum, popularly called 'pineapples', is a perennial herb from Chile's alto plano, sometimes grown in European gardens as a 'scent plant' by connoisseurs (the above photos are from the garden of the Faculty of Life Sciences, University of Copenhagen). The petal-less, composite flowers are about 1 cm across. The whole plant, and especially the flower-heads, give off a tremendous boost of fruity pineapple-like aroma when squeezed.
The essential oil of the dried flowers consists of 80 % esters, mainly of methyl-branched alcohols, e.g. 3-methyl-2-buten-1-ol (prenyl alcohol), 3-methyl-3-buten-1-ol and (Z)-2-methyl-2-buten-1,4-diol, with acetic acid (R = CH3) and short chain methyl-branched carboxylic acids. Moreover, it contains sesquiterpene lactones of toxicological and pharmacological interest, especially because of their cytotoxic and antitumor activities, e.g. aromatin [175].