ectocarpene, Calone 1951 ®, and a new experimental marine odorant
Ectocarpus siliculosus (Ectocarpaceae)
The olfactory impression of a fresh seashore is partly caused by algae metabolites. Certain brown algae excrete a number of linear and alicyclic C11-hydrocarbons as pheromones. The algae Ectocarpus siliculosus, for example, emits an alkatriene named ectocarpene with a smell reminiscent of tomato leaves.
In perfumery, marine nuances are achieved using a methylbenzodioxepinone named Calone 1951 ® (discovered by Pfizer in 1966). This unusual odorant has a very intense 'sea-breeze' note with floral overtones and is the basis of several perfumes of the marine trend, starting in the nineties. L'eau d'Issey pour homme (I. Miyake 1994), Polo Sport Woman (R. Lauren 1996) and Aquawoman (Rochas 2002) are examples [43].
In a recent study of Calone homologs by Givaudan scientists, the derivate 7-(3-methylbutyl)benzo[b][1,4]dioxepin-3-one turned out to be very interesting, with an intense and diffusive, linear, marine odour, fresher and crisper than Calone and with an odour threshold as low as 0.014 ng/L air [44].
the strongly odoriferous 'sulphur-terpenoids'
from buchu leaf
Buchu leaf
Agathosma betulina, A. crenulata (Rutaceae)
The buchu has a restricted natural distribution area in the Western Cape
province in South Africa where it is found on sandy mountain slopes near
Niewoudtville, Piketberg and Tulbagh and in the Cederberg Mountains. It
is an evergreen, multi-stemmed, fragrant shrub growing to a height of
2 m. The buchu leaves have multitudes of round oil glands and are collected
for pharmacological and flavour/perfumery use. The Hottentots used them
for perfuming their bodies. However, the Cape Government now exercises
strict control over the gathering of buchu leaves and has lately made
the terms and conditions more onerous. In order to prevent the wholesale
destruction of the wild plants, no person is permitted to pick or buy
buchu without a licence [14]. The traditional pharmacological use encompasses
the treatment of kidney and urinary tract infections, colds, stomach ailments,
rheumatism, gout and fever. A. betulina is the more valuable
species as it has the lowest pulegone level, a compound considered to
be toxic.
Buchu leaf oil is obtained by steam distillation of the leaves as a dark
yellow to brown liquid with a characteristic, strong, minty-fruity odour,
reminiscent of black
currant. The major components of the oil are menthone and isomenthone,
diosphenol, limonene, pulegone and isopulegone. However, the constituents
responsible for the characteristic black currant odour are p-menthane-8-thiol-3-one
(mercapto-menthone) and its S-acetate (ca. 3 %). They are two examples
of the small number of naturally occurring sulphur-containing terpenoids
known to date [6][14].
Apart from its pharmacological use, buchu leaf oil is used as a flavour
ingredient (e.g., in fruit aromas) and in perfumery. The black currant
or 'Bourgeons de Cassis' note of buchu leaf oil is valued in certain types
of Chypre bases and Colognes. Only very small amounts are employed because
of the intensity of the oil.
Etymology: Gr. agathos, pleasant; Gr. osme, smell.
Bucku, the name used by the Hottentots.
oxoisophorone, oxoisophoroneoxide and
(E)(E)-alpha-farnesene
Buddleja davidii (Buddlejaceae) Butterfly bush
Butterfly bush is native to north-western China. It is a deciduous to semi-evergreen shrub with a weeping form that can get up to 3 m tall and have a spread of almost 5 m. It has opposite lance-shaped, grey-green leaves on long arching stems. The flowers are borne in long cone-shaped clusters. In Denmark, the butterfly bush is restricted to gardens, whereas in southern England it is almost a weed, growing everywhere on abandoned sites, e.g. on top of crumbling walls. There are many garden cultivars with flowers of different colour - purple, white, pink or red - but they usually have an orange throat in the centre.
The flowers are some of the most attractive to butterflies (and nocturnal moths also). In northern Europe they are especially visited by the Nymphalides hatching in late summer like Vanessa atalanta, V. cardui, Inachis io (photo), Aglais urticae and, now and then, Polygonia c album.
To the human nose, the flowers have a peculiar velvety sweetness. Andersson et al. identified 41 compounds in the flower headspace with (E)(E)-alpha-farnesene (20 %), oxoisophorone (45 %), and oxoisophoroneoxide (10 %) as the major constituents [12]. Interestingly, these compounds also elicit strong antennal response in the same butterflies [13].
important aroma compounds in plain dark chocolate
theobromine, caffeine and anandamide
Theobroma cacao (Sterculiaceae)
The cacao tree is a small underwood tree from the rainforests of tropical South America. It grows naturally in the low foothills of the Andes at elevations around 200-400 m in the Amazon and Orinoco river basins. The southern varieties are sometimes considered to be a species of their own, named T. leicocarpa. Today there are a multitude of cultivars and cacao is extensively grown in the tropics (West Indies, Java, Ghana, etc.).
The processing of cacao begins with a fermentation of the white pulp or mucilage covering the seeds. This fermentation is crucial, not only to the formation of significant volatile fractions (alcohols, esters and fatty acids), but also for the development of flavour precursors in the seeds (amino acids and reducing sugars). The thick pulp liquefies as it ferments and trickles away, leaving the seeds behind to be collected. The fermented and dried fatty seeds ready for export are now called cocoa.
By roasting the seeds, Maillard reactions converts flavour precursors formed during fermentation into three main classes of aroma compounds: aldehydes, O-heterocycles and pyrazines [123] [124]. The roasted seeds are then crushed and freed of their hulls and germs, and ground into a thick creamy paste called cocoa mass or cocoa liquor. Part of this is separated in cocoa powder and cocoa butter (last two photos).
For chocolate production, the cocoa mass is mixed with sugar, additional cocoa butter, emulsifier and, most often, vanilla or vanillin as an additional flavouring. A final process called conching (because of the shape of the original machinery) consists of grinding and aerating the liquefied chocolate for a prolonged period of time, thereby dehydrating and oxidizing the mass. This important step reduces tannins and improves the consistency and aroma of the chocolate [125].
The characteristic acidulous-bitter taste of dark chocolate is due to an interplay of tannins and theobromine plus a number of diketopiperazines, the latter being formed during the roasting process [126].
Cocoa butter is a unique vegetable fat in that it consists mainly of three triglycerides: palmitic-oleic-palmitic, palmitic-oleic-stearic and stearic-oleic-stearic. This composition of very uniform triglycerides provides a unique melting characteristic, making the chocolate melt slightly below 37 °C. Pure cocoa butter is used in white chocolate, and in various pharmaceutical and cosmetic applications.
Theobromine (1.5 - 3 % of the cocoa mass) and small amounts of caffeine are the CNS stimulants in cocoa [127]. The detection of arachidonoylethanolamine (anandamide), a brain constituent that binds to the cannabinoid receptor, in chocolate and cocoa powder has received particular attention [124].
Thanks to an exceptionally high procyanidin content, chocolate and cacao powder displays a high antioxidant activity [128].
Etymology: Gr. theos, god, Gr. broma, food, 'food of the gods'. Mixe-Zoquean cacao.