Extraction of Fragrance Materials [Aromatic Compounds] from Sources

Extraction of fragrance materials is a crucial step to get aroma ingredients for a beautiful fragrance to come into existence. A divine smell of fragrance, a soulful aroma of an attar or a sensual perfume exists because of the extracted ingredients are there. Fragrance Industry uses 3000+ fragrant material to make fragrance oils, Attar, flavours and perfumes. Some of these fragrant ingredients are extracted from plants and animal sources while others are synthesized in laboratories.

The quality of extracts/fragrant ingredients is largely responsible for quality of fragrances that you make. Further, you cannot apply same extraction process in separation of fragrant material in every case. In fact, the extraction processes have to be case specific. An extraction process suitable for extraction of a fragrant material ‘A’ can be averse for ‘B’. Understandably, knowledge of various extraction process is of immense significance if you are into making of attar/perfume oils, fragrance oils, aromatherapy oil etc.

As per Wikipedia fragrance extraction refers to the separation process of aromatic compounds from raw materials using various methods. Chiefly, these methods could be distillation, solvent extraction, expression, sieving, or enfleurage. And, results of extraction are either essential oils, absolutes, concretes, or butters, depending on the amount of waxes in the extracted product. Fragrance Crafting in India and hence extraction of fragrance materials is an age-old activity. Accordingly, it is but natural for Indian perfumers to make some best attars in India.

1. Extracting Fragrance Material by Solvent Extraction

(a) Organic Solvent Extraction

Method of organic solvent extraction is most common and most economic for extracting aromatics in the modern perfume industry. Under the process, raw materials are submerged and agitated in a solvent that can dissolve the desired aromatic compounds. Hexane and Dimethyl Ether are most common solvents for process of solvent extraction/ maceration.

Since, this technique uses low temperatures so, the extracts are closer to the original scent of the raw material. Many of the best attar brands in India go for this process for original natural smell in their fragrance. The extract obtained is called concrete which is a mix of essential oil, waxes, resins, and other lipophilic (oil-soluble) plant material.

The concretes are highly viscous and even solid least suitable for direct use in fragrance making. A further process of extraction of fragrant oil from the concrete is employed in and the concentrated fragrant oil called absolute, is obtained.

(b) Supercritical Fluid Extraction

It is rather a new technique for extracting fragrance Ingredients which employs in Supercritical CO2 as extraction solvent. CO2 in a non-polar compound and has low surface tension so fluid CO2 makes relatively unreactive solvent, wets easily and can extract the hydrophobic aromatics from the plant material. As the technique uses low heat (high pressure of course) the extracted essence compounds are closest to the original odour of raw material. On withdrawal of pressure, fluid CO2 turns to gas at room temperature itself and also leaves no trace of itself in the final product.

Through this process you get the absolute directly without having to deal with a concrete. And, absolute produced using this process are known as CO2 extracts.

(c) Ethanol Extraction

You can use this technique to produce extracts from dry raw materials, impure oils or concretes (obtained from organic solvent method, expression, or enfleurage). Ethanol Extracts from dry materials are called tinctures, while Ethanol Extracts from purifying oils and concretes are called absolutes.

Ethanol, is less hydrophobic than solvents employed in for organic extraction. So, it dissolves more of the oxidized aromatic constituents (alcohols, aldehydes, etc.), leaving behind the wax, fats, and other highly hydrophobic substances.

From the resultant washes, the alcohol is evaporated under low-pressure and it leaves behind absolute. Notably, the ethanol extraction is not appropriate to extract essences from fresh plant materials.

2. Extraction of Fragrance Material through Distillation

Distillation is most common technique for obtaining fragrance ingredients from fresh plants and parts thereof. Raw plant material, that might include flowers, leaves, wood, bark, roots, seeds, or peel, is put into an alembic (distillation apparatus) over water. The “cucurbit” or the STILL pot containing raw material is heated and fragrant compounds are re-collected through condensation of the distilled vapor.

Distilled extracts so collected, are called either essential oils or ottos. Although, this technique is basic in nature, but is in use for ages for its effectiveness. Many quality fragrance oil makers including best attar brands in India employ in this method extensively. Alembic is a fancy word for native arrangement of Deg & Bhapka having wide scale use in Kannauj, the fragrance city of India.

(a) Steam Distillation

Under this method Steam from boiling water is made to pass through the raw material for 60–105 minutes, which takes away most of their volatile fragrant compounds. The condensate in the process is made to settle in a flask. Obviously, this contains both water and the aromatic material in form of essential oil.

Because oil floats on the top of the distillate, you can easily separate fragrant oils from the water. Steam Distillation is most suitable extraction method where fresh plant materials such as flowers, leaves, and stems are raw material. Delicate essential oils needed for some top quality fragrance oils are extracted through this technique.

(b) Dry/Destructive distillation

Notably, this technique uses direct heating of raw material without a carrier solvent such as water. Method is useful in extraction of fragrance oil from fossil amber and fragrant woods. Fragrant compounds resulting under this method mostly undergo anhydrous pyrolysis due to high heat. As a result, different fragrant compounds and hence different fragrant notes can evolve.

Only because of anhydrous pyrolysis, the method gives fragrance oils a “burned” or “toasted” odour. Many top fragrance oil brands use extracts with such unusual odour to add USP to their fragrances and sell at high prices.

(c) Fractionation Distillation

This technique uses fractionation column which is useful in separating fragrance oils of different densities and hence different aroma.

Although, fractionation distillation is an expensive process but, it enables the perfumers to manipulate with the final scent in a great way. Perfumers also employ in the method to remove undesirable scents from extracts. Top fragrance oils with sophisticated composition must have used extracts obtained through this method.

3. Extraction of Fragrance Material by Method of Expression

Importantly, expression method facilitates extraction of essential oils by hard pressing, squeezing or compressing raw materials. The method came into practice even before the distillation and is still in use in Egypt.

Obviously, the aromatic oils you get through this process have very close odour to the raw ingredients. Some of the fragrance oils using natural fragrant ingredient prefer extracts out of this method. This help them mimic original smell of plants essential oils.

Today, the expression plays main extraction method for extracting fragrant oils from the peels of fruits in the citrus family. Reason being, large quantity of oil present in the peels of these fruits make this method highly suitable and economical too.

4. Extraction of Fragrance Material by Method of Enfleurage

Both expression and enfleurage are the best when it is likely that heat would denature the aromatic /fragrant compounds. Expression is although in practice even today but enfleurage is least in use. Discontinuation of the method happened mainly because the process is super expensive and more efficient ways of extractions are accessible.

On academic note, enfleurage is a two-step process. In the first stage, fragrant essence is absorbed into wax or fat, In the second stage, the extraction is done with alcohol as solvent. You would hardly find any good name in fragrance oil maker using this method for extraction of fragrant materials.

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Extraction of Fragrance Materials- Separating Aromatic Compounds from Raw Sources