Extraction Methods: Solvents

Supercritical Carbon Dioxide CO2 Extraction

This is the first choice for aroma extraction, decaffeination, defatting, pesticide removal, phytoextraction, and sterilization. It has become an important commercial and industrial method to extract chemicals due to its low toxicity and environmental impact.

The process uses a relatively low temperature and with the stability of CO2 it allows for compounds that are extracted from plant sources like essential oils to encounter limited damage or chemical denaturing.

Supercritical CO2 is the fluid state of carbon dioxide and it is temperature and pressure is held at or above its critical stage. When this happens CO2 can adopt properties midway between a gas and a liquid. It begins to behave as a supercritical fluid, expanding to fill a container like a gas but with a density that of a fluid.

Supercritical fluid is where distinct liquid and gas phases are non-existent.  It causes molecules to go through solids like a gas and dissolve materials like a liquid.  Small changes in pressure and temperature when close to its critical point – where phases in boundaries do not exist it will allow for many properties to be re-fined within that extracted material.

The common solvents used in this method of extraction instead of chemical solvents are CO2 and water as supercritical fluids.

The cost can be prohibitive however the yield of the essential oils is superior in quality and sterilization.

 

http://en.wikipedia.org/wiki/Supercritical_carbon_dioxide

Extraction methods of essential oils

Extractions methods are the most important aspect of getting the highest quality yield of an essential oil. The best extraction methods usually will minimize damage to the plant material and the essential oil.

The wrong application of extraction to a particular plant material can and will destroy the chemical signature and damage the oil.

These are some of the methods of extraction that are used:

1.    CO2—1st choice for aroma extraction, decaffeination, defatting, pesticide removal, phytoextraction, and sterilization.

2.    Distillation - converts the volatile liquid (the essential oils) into a vapor and then condenses the vapor back into a liquid.

It is the most popular, and cost effective method in use today in     producing essential oils. There various methods within this category:

a)   Water distillation

b)   Steam distillation

c)    Hydro diffusion

d)   Cohobation

e)   Rectification

f)     Water and steam distillation

g)   Fractional distillation

3.    Expression - is a cold pressed method of extraction, which is       mostly used in the extraction of citrus essential oils.

a)   Sponge expression

b)   Ecuelle a piquer

c)    Machine abrasion

4.    Solvent extraction – this is a method where solvents are used to coax the essential oils out of the botanical material and there are various ways are also used in this method.

a)   Maceration

b)   Enfleurage

c)    Solvent

d)   Hypercritical Carbon dioxide CO

Anatomy of essential oils

Essentials oils are extracted from different parts of the plants.
The anatomy of essential oils deals with where the essentials oils are best extracted from.
Some parts of a plant may yield different essentials oils. 
Essentials oils can be sourced out from different parts in varied concentrations and differ in their scents and therapeutic qualities.
Resins are usually from the congealed saps of trees or plants
like frankincense, galbanum, myrrh. 
The essential oils are extracted from these congealed resins.
Florals scents are usually extracted from flowers like roses, jasmine, ylang ylang. 
More woodsy scents are from the bark or the plant or tree like cedarwood, sandlewood.
Usually the scent will reveal what part the essential oils are yielded from. 
Concertrations of essential oils in a plant or tree are found 
in varied strengths depending on the anatomy of the plant.

Berries ▪   Allspice ▪   Juniper Seeds ▪   Almond ▪   Anise ▪   Buchu ▪   Celery ▪   Cumin ▪   Nutmeg oil Bark ▪   Cassia ▪   Cinnamon ▪   Sassafras Wood ▪   Camphor ▪   Cedar ▪   Rosewood ▪   Sandalwood ▪   Agarwood Rhizome ▪   Galangal ▪   Ginger

Leaves ▪   Basil ▪   Bay leaf ▪   Buchu ▪   Cinnamon ▪   Common sage ▪   Eucalyptus ▪   Lemon grass ▪   Melaleuca ▪   Oregano ▪   Patchouli ▪   Peppermint ▪   Pine ▪   Rosemary ▪   Spearmint ▪   Tea tree ▪   Thyme ▪   Tsuga ▪   Wintergreen Resin ▪   Benzoin ▪   Copaiba ▪   Frankincense ▪   Myrrh

Flowers ▪   Cannabis ▪   Chamomile ▪   Clary sage ▪   Clove ▪   Scented geranium ▪   Hops ▪   Hyssop ▪   Jasmine ▪   Lavender ▪   Manuka ▪   Marjoram ▪   Orange ▪   Rose ▪   Ylang-ylang Peel ▪   Bergamot ▪   Grapefruit ▪   Lemon ▪   Lime ▪   Orange ▪   Tangerine Root ▪   Valerian