Natural aromas

Designations for reinforced flavourings are aroma natural reforcado de... or aroma reforcado de. .. (3.5.), for reconstituted flavourings aroma reconstitudo de. .. or aroma de. .. reconstitudo (3.6.). Natural flavourings without defined flavour are called natural composto and they can be given fantasy names (3.7.). Optional designations may indicate the specific intended use (3.8.). 

Guadagni D.G., Buttery R.G., Okano S. and Burr H.K. (1963b) Additive effect of sub-threshold concentrations of some organic compounds associated with food aromas. Nature (London) 200, 1288-9. 

The odour activity value (OAV) is a useful p>arameter to assess the relative importance of individual chemical components paesent in a wine. The aroma active compounds are volatiles whose concentration in wine is above their odour threshold (OAV>l). However, even when the OAV of a particular compoimd is less than 1, it still might contribute to the aroma of a wine as a consequence of some additive or synergic effect among compounds with similar aroma nature. 

Processing of natural products with supercritical fluids-based technologies has been an extensive area of research during the past two decades. In fact, since many valuable products occurring in natural compounds, such as vitamins, aromas, natural pigments or essential oils, are soluble in supercritical fluids, their extraction from natural materials is one of the most widely studied applications of supercritical fluids. To date, SFE technology is used at industrial levels in economically relevant processes such as decaffeination of both colTee and tea and extraction of hop constituents and spices [19]. 

These interactions may also influence the sensorial quahty and shelf life of the product and even lead to a total loss of smell or change the aroma nature. 

Suffice to say that anything that remotely smells like sassafras oil or licorice or any of those strong rustic spices is going to have some amphetamine precursor, maybe not safrole exactly, but definitely something. There is just no other substitute in nature for the aroma these unique compounds give. 

Many esters occur naturally Those of low molecular weight are fairly volatile and many have pleasing odors Esters often form a significant fraction of the fragrant oil of fruits and flowers The aroma of oranges for example contains 30 different esters along with 10 carboxylic acids 34 alcohols 34 aldehydes and ketones and 36 hydrocarbons... 

Aroma. Chemicals. Specialty chemicals produced either by extraction from natural sources or by synthesis, such as vanillin [121 -33-5],... 

Bl cetyl. Biacetyl [431-03-8] (2,3-butanedione) is a greenish yeUow liquid with a quinone odor. Biacetyl occurs naturally in bay oil and is readily soluble in organic solvents. It is a constituent of many food aromas, eg, butter, and is commonly used to flavor margarine. Flavor-grade biacetyl was available at 20.40/kg in July 1993, and is used as an odorant for coffee, vinegar, tobacco, and in perfumes. 

Rectified oils have been redistilled to improve a particular property or characteristic, such as flavor or aroma. Eor example, natural oil of peppermint is frequently rectified to remove dimethyl sulfide, which has a powerful and objectionable cooked vegetable note deleterious to the use of the oil in cmme de menthe Hqueurs. Distillation is also used to remove psoralens, which are harmful photosensitizing agents present in natural bergamot oil. Color may be removed, eg, from cassia oil, by vacuum steam distillation. A desirable component, such as 1,8-cineole (eucalyptol) 85% in eucalyptus oil, may be... 

A number of other valuable aroma chemicals can be isolated from essential oils, eg, eugenol from clove leaf oil, which can also, on treatment with strong caustic, be isomerked to isoeugenol, which on further chemical treatment can be converted to vanillin (qv). Sometimes the naturally occurring component does not requke prior isolation or concentration, as in the case of cinnamaldehyde in cassia oil which, on dkect treatment of the oil by a retro-aldol reaction, yields natural ben2aldehyde (qv). This product is purified by physical means. 

From a perfumery point of view, trace ingredients again play an important role in the typical aroma of citroneUa oil. In 1980, IFF chemists isolated and characterized two nonterpenic compounds, melonol (2,6-dimethyl-5-hepten-l-ol [4234-93-9]) and melonal (2,6-dimethyl-5-heptenal [106-72-9]) with interesting green-melon odors (10). Although neither of these had previously been reported in nature, melonal has been a product of commerce for a number of years. 

Synthesis. Exploratory research has produced a wide variety of odorants based on natural stmctures, chemicals analogous to naturals, and synthetic materials derived from available raw materials and economical processing. As in most areas of the chemical industry, the search for new and useful substances is made difficult by the many materials that have been patented and successfully commercialized (4). In the search for new aroma chemicals, many new materials are prepared for screening each year. Chemists who perform this work are involved in a creative exercise that takes its direction from the commercial sector in terms of desirable odor types and specific performance needs. Because of economic limitations, considerations of raw material costs and available processing methods may play a role eady in the exploratory work. 

Natural menthol is obtained by freezing the essential oU, eg, Mentha arvensis and the menthol crystals ate separated by centrifuging the supernatant hquid away from the crystals. The supernatant oU is then caUed dementholized cornmint oU. Impurities in the crystals come from the essential oU and usuaUy give a slight peppermint aroma to the crystallized menthol. The cornmint oU, rich in (—)-menthone (- 28%) and (—)-menthol (- 32%), can be further processed to give additional natural menthol. 

Ionones and Methyl Ionones Manufacture. The discovery of ionones and methyhonones was an early example of the need to develop synthetic fragrance materials because of the high cost of natural materials. The aroma of violet flowers was important to perfumery and led to the development of ionones and methyhonones at the end of the nineteenth century. 

In addition, vanillin was among the three or four aroma chemicals that helped perfumers of the past to imagine a new generation of fragrance combinations. The work done in organic chemistry by chemical companies has helped perfumers who had been restrained in their creation by the avadabihty of raw materials, which include natural oils and extracts made by the enfleurage process, ie, the property of perfumes to stick on fat and greases. Those extracts were weak, flat, and unpleasant. 

Carbon dioxide is used to increase the natural CO2 content of the beer and as counterpressure in tanks and filling machines. It must be free of water and any aroma. The consumption is 0—10 g/L of beer produced. In major breweries, carbon dioxide is bought in bulk, and in many breweries it is common practice to coUect the surplus CO2 from the fermentors to clean, dehumidify, and compress in a local CO2 plant which is easily automated. 

Of all the aromatic organic molecules P-phenethyl alcohol (PEA) (2) is probably the most prestigious aroma chemical in the world of perfumery. This is because of its exquisite odor of natural rose petals. 

The two isomeric butanals, n- and isobutyraldehyde, C HgO, are produced commercially abnost exclusively by the Oxo Reaction of propylene. They also occur naturally ia trace amounts ia tea leaves, certain oils, coffee aroma, and tobacco smoke. 

Phenyl-2-propenoic acid [621 -82-9] commonly referred to as cinnamic acid, is a white crystalline soHd having a low intensity sweet, honeylike aroma. It has been identified as a principal constituent in the botanical exudates from Styrax IJquidamber orientalis) Benzoin Styrax ben in Pern Balsam [Myroxylon pereirae and Tolu Balsam (]Ayro>ylon balsamum) (4,5). In these, as well as numerous other natural products, it exists both as the free acid and in the form of one or more of its esters, as for example, methyl cinnamate, ben2yl cinnamate [103 1 -3] and cinnamyl cinnamate. 

Cinnamaldehyde has been efficiently isolated in high purity by fractional distillation from cassia and cinnamon bark essential oils. This material has been utili2ed in several manufacturing protocols (39—41) for the preparation of natural ben2aldehyde through a retro-aldol process. Since the late 1970s the demand for natural flavors has increased dramatically. This demand has led to a corresponding requirement for a more extensive line of readily available natural aroma chemicals for flavor creation. 

The flavor of instant coffee can be enhanced by recovering and returning to the extract or finished dry product some of the natural aroma lost in processing. The aroma constituents from the grinders, percolation vents, and evaporators may be added dkectly or in concentrated or fractionated form to achieve the deskable product attributes. 

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