Methods of Volatile oil Extraction

• Methods used to obtain volatile oils

  • Distillation
  • Special methods
• Distillation processes used to obtain volatile oils

  • Water Distillation
  • Water and Steam Distillation
  • Direct Steam Distillation
• Special methods used to obtain volatile oils

  • Enzymatic hydrolysis
  • Plant expression
  • Enfleurage
  • Extraction
  • Destructive Distillation
  • Pneumatic Method
  • Maceration Method
• Characteristics of the material used in water distillation

  • Dried
  • Not injured by boiling
• Product derived from the water distillation process

  • Turpentine oil
• Equipment used in water distillation

  • Heat
  • Condenser
  • Separator
• Obtaining turpentine oil

  1. Crude turpentine oleoresin, sourced from plant exudate, rainwater, wood chips, pine needles, and others, is introduced into the distilling chamber

  2. Heat is applied until a volatile matter (oil and water) is condensed in the condensing chamber

  3. Turpentine oil is collected, which primarily consists of terpenes
• Material used in water and steam distillation

  Material that may be dried or fresh but could be injured by boiling
• Products obtained through water and steam distillation


  • Volatile oils from cinnamon
  • Volatile oils from clove
• Obtaining volatile oils from cinnamon and clove through water and steam distillation

  1. Grinding: The dried material is ground and then covered with a layer of water

  2. Generation of steam: Steam is generated elsewhere and piped into the container holding the macerated material

  3. Separation of layers: The oily layer is separated from the aqueous layer
• Final step in obtaining volatile oils through water and steam distillation

  The oil is marketed with or without further processing
• Equipment for Water and Steam Distillation

  • Steam supply
  • Condenser (Hot and Cold water)
  • Separator
• Material used in direct steam distillation

  Fresh plant drug
• Products obtained through direct steam distillation

  • Peppermint oil
  • Spearmint oil
• Obtaining peppermint and spearmint oils through direct steam distillation

  1. Crop is cut and placed directly into a METAL distilling tank on a truck bed

  2. The truck is driven to a distilling shed where steam lines are attached to the bottom of the distilling tank

  3. If the material is still green and contains considerable natural moisture, maceration is unnecessary

  4. Steam is forced through the fresh material and carries the oil droplets through a vapor pipe attached at the top of the tank to the condensing chamber
• Enzymatic hydrolysis

  Conversion of specific glycosides into their respective aglycones
• Enzymatic hydrolysis of gaultherin

  Gaultherin (glycoside) is converted by gautherase into methyl salicylate (aglycone) along with glucose and xylose
• Enzymatic hydrolysis of sinigrin

  Sinigrin (glycoside) is converted by myrosin into mustard oil
• Plant expression

  Employed when volatile oils are destructed or decomposed by other methods
• Products obtained through plant expression

  • Lemon oil
  • Bergamot oil
  • Orange oil
• Ecuelle method

  Puncturing the oil glands of the fruit by rolling it over a trough lined with sharp projections, penetrating the epidermis to reach the oil glands in the outer portion of the peel
• Scarification Process

  A specially designed apparatus introduced in France, consisting of a large bowl meant for pricking the outer surface of citrus fruits
• Pressing step

  Removes the oil from the glands, and a fine spray of water washes the oil from the mashed peel while the juice is extracted through a center tube that cores the fruit
• Oil-water emulsion separation


  Separated by centrifugation
• One variation in the plant expression process is to remove the peel from the fruit before extracting the oil
• Enfleurage

  Used to capture fragrant compounds from flower petals, especially when the volatile oil component is small
• Fats used in Enfleurage

  • Odorless fats that are solid at room temperature
• Enfleurage was extensively used in the past for the production of pomades and perfumes
• Reason for using Enfleurage

  Oil removal is not commercially feasible using other methods when the volatile oil component of petals is small
• Enfleurage process

  1. An odorless, bland fixed oil or fat is spread in a thin layer on glass plates

  2. Flower petals are placed on the fat for a few hours

  3. Old petals are removed, and a new layer of petals is introduced

  4. After the fat has absorbed as much fragrance as possible, the oil is removed by extraction with alcohol
• Solvents used in extraction

  Petroleum ether or benzene
• Advantage of extraction over distillation

  Allows for the maintenance of uniform temperatures, typically around 50 degrees Celsius, which cannot be achieved through distillation
• Characteristic of extracted oil compared to distilled oils

  The extracted oil has a more natural odor that is unmatched by distilled oils, as distilled oils may have undergone altered chemical constituents due to high temperatures
• Extraction is important in the perfume industry, despite being more costly than the distillation method
• Equipment used for Extraction

  • Solvent
  • Vacuum Distillation (removes alcohol)
  • Condenser
  • Absolute
• Destructive Distillation

  A means of obtaining empyreumatic oils
• Destructive Distillation


  1. The sample is heated without access to air, leading to decomposition and the release of volatile compounds

  2. The resultant mass is charcoal

  3. The condensed volatile matter separates into two layers: Aqueous layer containing wood naphtha and pyroligneous acid, Tarry layer in the form of pine tar, juniper tar, or other tars depending on the type of wood introduced
• Pneumatic Method

  A method used for extracting volatile oils from flowers
• The basic principle behind the Pneumatic Method is similar to that of the enfleurage method
• Pneumatic Method

  1. Current or warm air is passed through the flowers

  2. The subsequent air, loaded with suspended volatile oil particles, is directed through a fine spray of molten fat in a closed chamber, where the volatile oil gets absorbed promptly