There are many different methods used to extract various compounds from botanicals. Durning an extraction process a solvent is used to draw out the plant extracts, common solvents utilised are water or alcohol. Once the desired compounds are extracted the solvent is then removed. The plant extraction method used depends on whether specific compounds of the plant are desired to be extracted or the full range of plant compounds. Here we take a close look at the different methods of extraction.
Extraction Methods Explained
1. LIPOPHILIC EXTACTION // Lipophilic are oil loving (fat soluble) and therefore soluble in oil. Macerated or Infused oil are Lipophilic extracts. This includes fat soluble vitamins (A, D, E, K), carotenoids, bisabolol and other lipophilic active ingredients. Note: Vitamin C is an extremely sensitive hydrophilic vitamin and therefore it is NOT present in plant oils, however some plant oils exhibit Vitamin C behaviours, research, I am sure one day may explain these 'effects'.
HOW IT WORKS // Plant material is added to a carrier oil. Maceration is performed as cold or warm-cold. Usually the procedure takes a few days to several weeks and the plant material is renewed several times during the maceration period. Heat or sun are applied as sources of energy.
Ingredient Example // St Johns Wort Infused Oil
2. SUPERCRITICAL EXTRACTION (CO2) //Supercritical extraction uses CO2 (Carbon dioxide - an oxygen-free process) instead of organic solvents.
HOW IT WORKS // At a temperature and pressure above its critical point, a molecule will become a supercritical fluid, which is not quite a gas, but not quite a liquid. Supercritical fluids can be used under high pressure to extract a full range of phytochemical types. CO2 has a high diffusion rate that can penetrate the material quickier than liquids. It is a pure substance found in nature and is, thus, easily removed from the final extract without leaving any residue.
Among its advantages, supercritical CO2 extraction has the flexibility to extract specific compounds, and it operates at temperatures lower than expeller press and organic solvent methods. It also involves no oxygen, thus better preserving the extracted compounds.
CO2 extraction delivers the superior active properties of the plant without the use of any chemical solvents or the production of residues & impurities or issues with rancidity. Supercritical CO2 extraction is not ideal for all ingredients, this method is only applicable to materials that are lipid soluble.
Ingredient Example // Pomegranate Seed Oil
3. DISTILLED EXTRACTION
This method is used for Essential Oils.
HOW IT WORKS // Steam distilling is a method of extraction which collects only the light, volatile oils known as essential oils. This technique involves either placing fresh herb in a vessel of boiling water or suspending the herb above the boiling water in a perforated basket so that steam passes through the herb. In either case, the steam strips the light oils from the plant material and carries it to a chilled condenser where the oil-entrained steam liquefies.
The condensed fluid separates into two layers: the lower layer is called hydrosol. It is a milky looking liquid composed of water soluble oil and water. Floating on top of the hydrosol will be a thin layer of essential oil.
Ingredient Example // Chamomile Essential Oil
4. HYDROPHILIC EXTRACT //
The term 'Hydrophilic' is given to compounds that are soluble in water. (water is polar and oil is non-polar) ingredients such as flavonoids, tannins and anthocyanidins are being extracted by this method.
HOW IT WORKS // Ultrasound-Assisted Extraction (UAE) is based on the production of ultrasound waves and their transmission throughout a solvent resulting the formation of bubbles. When the bubbles collapse, there is a generation of liquid circulation currents and turbulence that improve the mass transfer rate. The fractures formed in the cell wall enhance its permeability and so a bigger amount of solvent can enter into the plant tissues to extract the bioactive compounds.
Ingredient Example // Nettle Extract
5. COLD PRESSED //
The cold pressing process does not need an external substance as with other methods. The seeds, nuts or fruit are crushed and pressed in order to force the oil out. Though the friction caused by the pressure does increase the temperature of the product, this is not high. Manufacturers must keep it within a certain degree range to be able to claim that the oil is cold pressed. For instance, to obtain jojoba oil without damaging the properties it cannot exceed 45°C.
HOW IT WORKS //
- The process begins with the filtering stage, in which the seeds will be passed through a series of spaces with air propulsion systems. This process removes any impurities.
- Milling: The nuts, seeds, or fruits are ground into a paste using heavy granite millstones or modern stainless steel presses, which are found in large commercial operations.
- Pressing: The semi-solid paste is slowly stirred, often with a rotating screw which encourages the oil to separate from the solid parts and clump together. Once this happens, pressure is applied to force the oil out. It is one of the most important moments of the whole process, since this pressure may increase the temperature of the dough. If it exceeds a certain temperature, the oil may lose some of its properties.
- Filtering: The pressed oil goes through a series of filters that separate small pieces of peel or pulp of the fruit from the oil. The final part of this filtering process involves passing the oil through a cloth or paper to ensure that all impurities are removed from the oil.
- Once the filtering process is complete, a decantation process is carried out. Any remaining sediement is seperated from the oil by the simple force of gravity. Thus, a 100% pure and natural oil that retains all its properties will be obtained.
Ingredient Example: Milk Thistle Seed Oil
6. HYDROSOL //
Also known as hydrolats, distillate waters or floral waters. A hydrosol is the aromatic water that remains after steam-distilling or hydro-distilling botanical material - an example rose.
HOW IT WORKS // Most hydrosols are produced simply as a result of essential oil distillation. The plant matter used in the distillation process imparts the hydrosol with the water-soluble aromatic and therapeutic properties of the plant.
Unlike essential oils that should be diluted prior to application to the skin, hydrosols are much gentler than their essential oil counterparts and can generally be used directly on the skin without further dilution. There are Expert hydrosol distillers, who specifically distill plants for the resulting hydrosol that they produce. This can result in hydrosols with superior aroma and therapeutic benefit. Hydrosols can be used in place of water in creating natural fragrances, lotions, creams, facial toners and other skin care products. They can also be added to the bath, and used on their own as a light cologne or body spray.
Ingredient Example: Rose.
7. POWDER EXTRACT //
Powdered herbs are raw (crude or prepared) herbs that are ground or pulverised into a powder. They may be single herb products or formulas (combinations of herbs). They are not extracted or cooked.
HOW IT WORKS // Powders are dried decoctions. Manufacturers use organic chemical solvents to extract chemical ingredients that are less soluble in water or ethanol or to improve the concentration of a specific marker chemical in order to enhance the ingredient profile of the extract.
The most common method to make a powder is to spray dry the liquid extract. Spray drying is a method of producing a dry powder from a condensed liquid or slurry by rapidly drying with a hot gas such as nitrogen, oxygen or air. This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals. The resulting powder has a consistent particle size distribution and generally is free-flowing. A disadvantage to this method is that spray dried powders are very hygroscopic and even small amounts of exposure to water vapor (such as that normally found in air) may cause them to clump into a gummy or solid mass.
Ingredient Example // Matcha (powdered green tea)
We have chosen to use a combination of extraction methods encompassing Cold Pressed Oils, Distilled Essential Oils, Supercritical CO2 Extracts along with Infused Oils to gain the maximum beneficial compounds from each ingredient during our formulation process of our Hero product launching 2019
Until next time..
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Cold Pressing Method -
Modern extraction techniques
What are hydrosols