Clove Oil Extraction Methods, Process Guide

Clove oil extraction process

Today, the topic is the Clove oil extraction process.

Clove (Syzygium aromaticum) is an aromatic spice used by several cultures around the world. It is also known as clove bud, it has been cultivated in Europe since the 16th century for its culinary uses, mostly in curried dishes, spicy fruit cakes, and sauerkraut. Like other spices, clove bud can be used to create an essential oil that may benefit your health.

What is clove bud oil? Clove bud oil is derived from the clove tree, a member of the Myrtaceae family native to Indonesia and West Indies. The clove plant itself is typically found in low-lying areas that have a humid climate. It is a hardy plant, growing well in poor-quality soil (but not sandy soil).

A fully grown clove tree can reach a height between 10 meters and 12 meters (approximately 32 to 39 feet), with tough evergreen leaves. The flowers or buds are clustered and generally forked into three peduncles or “stems” as they are often called.  Clove oil has been promoted as having a wide range of health effects, but there is insufficient medical evidence to maintain general claims for its use as a therapeutic.

Dried Cloves.
Dried Cloves.

Clove oil properties

Clove oil has a warm, strong, spicy smell and the clove oil is colorless to pale yellow with a medium to watery viscosity. How does clove bud oil work? Clove oil is often applied topically, and when mixed with other oils like coconut oil and olive oil, it can function as a massage oil. To help ease respiratory illnesses, clove bud oil can be used in steam inhalation. It may be mixed in skin care products to enhance their benefits. There are some specific ways on how to use this plant oil:

  • Dab infused clove oil on a rag and rub it on your skin to help moisturize it.
  • When dealing with oral pain, place a drop of infused clove oil on the affected area.
  • Applying clove bud oil on your temples or forehead could help soothe headaches.
  • Clove bud oil may work as an insect repellent when rubbed on your skin.
  • Vaporizing clove bud oil could help eliminate lingering odors in your home, such as after cooking unpleasant-smelling foods.
  • Interestingly, clove bud oil could work as a metal polish. Apply clove bud oil in a clean rag and wipe on metal surfaces to help create them shiny again.

Uses clove oil

  • Clove bud oil can be used for acne, bruises, burns, and cuts, keeping infection at bay and as a pain reliever. It also helps with toothache, mouth sores, rheumatism, and arthritis.
  • Clove oil is beneficial to the digestive system, effective against vomiting, diarrhea, flatulence, spasms, and parasites, as well as bad breath.
  • Clove oil is important for relieving respiratory problems, like bronchitis, asthma, and tuberculosis. The disinfecting property is helpful in cases of infectious diseases.
  • Placing a few drops of clove oil on a cotton ball and then placing the cotton ball in a linen cupboard will not fragrance the cupboard, but will help to keep fish moths at bay.
  • Clove oil is very useful for its disinfecting properties, relieving of pain, especially toothache, arthritis, and rheumatism. It is efficient when used for complaints of the digestion system.
  • It is also of use for skin problems, particularly for skin sores and leg ulcers and as an insect repellent.
  • Clove oil used as a blended massage oil to assist with diarrhea, bronchitis, chills, colds, rheumatism, and arthritis. For toothache, the outer jaw can be massaged with this clove oil. Utilize a low dilution of less than 1%.
  • When used in a cream or lotion, the positive effects of clove oil are the same as those of massage oil and can furthermore help to sort out leg ulcers and skin sores. Use in low dilution of less than 1%.
  • Clove bud oil can be included at a low rate as part of mouthwash for toothache.

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Extraction of clove oil

How is clove oil extracted? Clove oil can be extracted from the plant leaves, stem, and buds. We sell clove oil, which is extracted by water distillation, containing the desired lower percentage of eugenol.

Chemical composition of Clove oil

The major chemical components of clove oil are eugenol, eugenol acetate, iso-eugenol, and caryophyllene.

Supercritical CO2 extraction:

The difference between traditional distillation and supercritical extraction is that instead of heated water or steam, CO2 is used as a solvent in the latter process. The supercritical extraction procedure operates at temperatures between 95 to 100°F whereas steam distillation operates at temperatures between 140 to 212°F.

CO2 extracts are generally thicker than their essential oil counterparts and often give off more of the aroma of the natural herb, spice, or plant than a distilled clove essential oil. CO2 extracts have been said to contain more plant constituents than the amount extracted from the same plant using steam distillation.

Extraction of essential oil from clove buds was experimentally found using the Speed SFE (SuperFluid Extraction) instrument. Liquid CO2 was pressurized by using a high-pressure pump and then charged into the extraction column to the desired pressure. Then the pressure was controlled to an accuracy of about 1% over the measuring range. The extraction column was 32 ml with an inner diameter of 14.40 mm and 195 mm length, being packed with powdered raw materials and glass beads.

The extraction column was heated with an oven and its temperature was specified and controlled by a thermocouple to within ±1 C. The supercritical CO2 with dissolved compounds passed through a heated micrometer valve, and was subsequently extended to ambient pressure. The extract was precipitated in a collect vial at ambient pressure and temperature. A calibrated wet-test meter at a known temperature and pressure found the total amount of CO2.

For each extraction test, the extractor was charged with about 15 grams of ground clove bud powder. Carbon dioxide flow rates ranging about 2 l/min were used. The clove oil weight was measured by precision balance until no oil was extracted out from the clove bud powder.

Solvent extraction

This solvent extraction method employs food grade solvents like hexane and ethanol to isolate essential oils from plant material. It is the best fitting for plant materials that yield low amounts of essential oil, that are largely resinous, or that are delicate aromatics unable to withstand the pressure and distress of steam distillation. This technique also produces a finer fragrance than any type of distillation process.

Through this process, the non-volatile plant material such as waxes and pigments, are extracted and sometimes removed through other processes.

Once the plant material has been treated with the solvent, it produces a waxy aromatic compound known as “concrete.” When this concrete substance is combined with alcohol, the oil particles are released. The aforementioned chemicals used in the procedure, then remain in the oil and the oil are used in perfumes by the perfume industry or for aromatherapy purposes.

The clove bud samples (30 g) were weighed and transferred into a filter paper extraction thimble and inserted into a 500 ml reflux flask, then extracted with 250 ml absolute ethanol for about six hours in a Soxhlet apparatus. After the Soxhlet extraction process, extracts were concentrated using a rotary vacuum evaporator at 50°C.

Hydro and steam distillation

The plant (100 g of dried and ground clove buds) in 500 ml flask was submitted to hydrodistillation for 4 to 6 hours and steam distillation for 8–10 h. The volatile distillate was then collected until no oil drops out. The volatile distillate was saturated with sodium chloride and added with some ether. Then, the ether layer and hydro layer were divided by the funnel. After dehydrated by anhydrous sodium sulfate, the ether layer was extra heated in the 60°C water bath to make oil to be concentrated and the ether to be recovered. The clove oil was weighed and refrigerated prior to analysis.

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Equipment used in steam distillation:

  • Condenser
  • Distillation vessel
  • Steam pipe
  • Boiler
  • Separator
  • Oil collected tank

Extraction of clove oil by steam distillation:

Explain the principles by which steam distillation works? Some of the organic compounds are immiscible with water. Usually, these organic compounds have a low vapor pressure. After mixing them with water, however, the combination will distill when the sum of the two vapor pressures reaches atmospheric pressure. It follows, then, that this should happen below the boiling point of water. This process is called steam distillation.

Boiling of a liquid in a container or vessel open to the atmosphere occurs when the total vapor pressure reaches atmospheric pressure. When 2 or more immiscible liquids are heated, the total vapor pressure over these liquids is equal to the sum of the individual vapor pressures. This allows substances to be distilled that if heated on there have to higher temperatures, might suffer partial decomposition or charring. In this testing, the initial products of the steam distillation will be clove oil and water.

Place an adequate supply of water in the steam generator, attach it to the rest of the apparatus and set it to boil. If Quick fit apparatus is used for steam generation make sure that use anti-bumping granules in the steam generator. If the level of the boiling water in the steam generator falls too low, the structure will not work smoothly. Eliminate the heat, carefully loosen the safety valve, and top up the steam generator with hot water. Reconnect the whole thing and resume heating.

After that, collect the distillate. It must have a pale milky appearance. Using the dropping funnel as a receiver at this point will facilitate the next phase of the separation. After 20 to 30 minutes disconnect the steam generator to avoid the possibility of suck-back troubles and turn off the heat under it. You will have possibly collected between 40 and 50 cm3 of distillate. Note the smell of the distillate.

Steam distillation procedure:

Disconnect the dropping funnel from the rest of the equipment. Include about 8 cm3 of cyclohexane to the distillate in the dropping funnel. Stopper the dropping funnel and shake the mixture. Release any pressure build-up carefully after each shake by inverting the dropping funnel though holding the stopper and slowly opening and shutting the tap.

Run the lower aqueous layer off. Collect the top layer and this contains the clove oil and the cyclohexane. Dry the organic layer by shaking with the anhydrous sodium sulfate in a conical flask. If possible, allow locating overnight, before removing the solids by filtration or decanting.

Separate the more volatile cyclohexane from the clove oil by placing the mixture in a little beaker whose mass is known on a water bath in a fume cupboard. The cyclohexane evaporates, leaving the clove bud oil behind. (Note that if the cyclohexane is to be distilled off it will boil at 81°C.)

That’s all folks about Clove Oil Extraction procedure.

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