Sunday, July 25, 2010

Aromatics sources

Plant sources

Plants have long been used in perfumery as a source of essential oils and aroma compounds. These aromatics are usually secondary metabolites produced by plants as protection against herbivores, infections, as well as to attract pollinators. Plants are by far the largest source of fragrant compounds used in perfumery. The sources of these compounds may be derived from various parts of a plant. A plant can offer more than one source of aromatics, for instance the aerial portions and seeds of coriander have remarkably different odors from each other. Orange leaves, blossoms, and fruit zest are the respective sources of petitgrain, neroli, and orange oils.
  • Bark: Commonly used barks includes cinnamon and cascarilla. The fragrant oil in sassafras root bark is also used either directly or purified for its main constituent, safrole, which is used in the synthesis of other fragrant compounds.
  • Flowers and blossoms: Undoubtedly the largest source of aromatics. Includes the flowers of several species of rose and jasmine, as well as osmanthus, plumeria, mimosa, tuberose, narcissus, scented geranium, cassie, ambrette as well as the blossoms of citrus and ylang-ylang trees. Although not traditionally thought of as a flower, the unopened flower buds of the clove are also commonly used. Most orchid flowers are not commercially used to produce essential oils or absolutes, except in the case of vanilla, an orchid, which must be pollinated first and made into seed pods before use in perfumery.
  • Fruits: Fresh fruits such as apples, strawberries, cherries unfortunately do not yield the expected odors when extracted; if such fragrance notes are found in a perfume, they are synthetic. Notable exceptions include litsea cubeba, vanilla, and juniper berry. The most commonly used fruits yield their aromatics from the rind; they include citrus such as oranges, lemons, and limes. Although grapefruit rind is still used for aromatics, more and more commercially used grapefruit aromatics are artificially synthesized since the natural aromatic contains sulfur and its degradation product is quite unpleasant in smell.
  • Leaves and twigs: Commonly used for perfumery are lavender leaf, patchouli, sage, violets, rosemary, and citrus leaves. Sometimes leaves are valued for the "green" smell they bring to perfumes, examples of this include hay and tomato leaf.
  • Resins: Valued since antiquity, resins have been widely used in incense and perfumery. Highly fragrant and antiseptic resins and resin-containing perfumes have been used by many cultures as medicines for a large variety of ailments. Commonly used resins in perfumery include labdanum, frankincense/olibanum, myrrh, Peru balsam, gum benzoin. Pine and fir resins are a particularly valued source of terpenes used in the organic synthesis of many other synthetic or naturally occurring aromatic compounds. Some of what is called amber and copal in perfumery today is the resinous secretion of fossil conifers.
  • Roots, rhizomes and bulbs: Commonly used terrestrial portions in perfumery include iris rhizomes, vetiver roots, various rhizomes of the ginger family.
    Seeds: Commonly used seeds include tonka bean, carrot seed, coriander, caraway, cocoa, nutmeg, mace, cardamom, and anise.
  • Woods: Highly important in providing the base notes to a perfume, wood oils and distillates are indispensable in perfumery. Commonly used woods include sandalwood, rosewood, agarwood, birch, cedar, juniper, and pine. These are used in the form of macerations or dry-distilled (rectified) forms.

Animal sources

  • Ambergris: Lumps of oxidized fatty compounds, whose precursors were secreted and expelled by the sperm whale. Ambergris is commonly referred to as "amber" in perfumery and should not be confused with yellow amber, which is used in jewelry. Because the harvesting of ambergris involves no harm to its animal source, it remains one of the few animalic fragrancing agents around which little controversy now exists.
  • Castoreum: Obtained from the odorous sacs of the North American beaver.
    Civet: Also called Civet Musk, this is obtained from the odorous sacs of the civets, animals in the family Viverridae, related to the mongoose. The World Society for the Protection of Animals investigated African civets caught for this purpose.[12]
  • Hyraceum: Commonly known as "Africa Stone", is the petrified excrement of the Rock Hyrax.[13]
  • Honeycomb: From the honeycomb of the honeybee. Both beeswax and honey can be solvent extracted to produce an absolute. Beeswax is extracted with ethanol and the ethanol evaporated to produce beeswax absolute.
  • Musk: Originally derived from the musk sacs from the Asian musk deer, it has now been replaced by the use of synthetic musks sometimes known as "white musk".

Other natural sources

  • Lichens: Commonly used lichens include oakmoss and treemoss thalli.
  • "Seaweed": Distillates are sometimes used as essential oil in perfumes. An example of a commonly used seaweed is Fucus vesiculosus, which is commonly referred to as bladder wrack. Natural seaweed fragrances are rarely used due to their higher cost and lower potency than synthetics.

Synthetic sources

Many modern perfumes contain synthesized odorants. Synthetics can provide fragrances which are not found in nature. For instance, Calone, a compound of synthetic origin, imparts a fresh ozonous metallic marine scent that is widely used in contemporary perfumes. Synthetic aromatics are often used as an alternate source of compounds that are not easily obtained from natural sources. For example, linalool and coumarin are both naturally occurring compounds that can be inexpensively synthesized from terpenes. Orchid scents (typically salicylates) are usually not obtained directly from the plant itself but are instead synthetically created to match the fragrant compounds found in various orchids.

Characteristics
Natural and synthetics are used for their different odor characteristics in perfumery

Variance

  • Naturals: Vary by the times and locations where they are harvested as well as how the product was extracted from the raw material. It's much more difficult to produce consistent products with equivalent odor over years of harvest and production. As such, the perfumer has to "manually" balance-out the natural variations of the ingredients in order to maintain the quality of the perfume.
  • Synthetics: Much more consistent than natural aromatics. However, differences in organic synthesis may result in minute differences in concentration of impurities. If these impurities have low smell (detection) thresholds, the differences in the scent of the synthetic aromatic will be significant.

Components

  • Naturals: Thousands of chemical compounds; large potential for allergies.
  • Synthetics: Depending on purity, consists primarily of one chemical compound.

Scent Uniqueness

  • Naturals: Bears a somewhat similar scent to its originating material, depending on the extraction method.
  • Synthetics: Similar to natural scents if the compounds are the same. Novel scent compounds not found in nature will often be unique in their scent and dissimilar to the scents of any naturals.

Scent Complexity

  • Naturals: Deep and complex fragrance notes. Softer with subtle scent nuances.
  • Synthetics: Pure and pronounced fragrance notes. Structural and defined.

Price

  • Naturals: Perfume composed of largely natural materials are usually much more expensive.
  • Synthetics: Perfumes using largely synthetic aromatics can be available at widely-affordable prices. Synthetic aromatics are not necessarily cheaper than naturals, with some synthetics being more costly than most natural ingredients due to various factors such as the complexity of synthesis or extraction procedure. However, due to their low odor threshold, one does not need to use much of these materials to produce a perfume.

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