The most common method used to separate the oils of plants is steam distillation. The plant whose oil is to be separated is placed in a large stainless steel container and steam is injected into the container. The aromatic molecules of the plant are exposed and evaporate, and the evaporated plant components pass into the condensation vessel. The steam becomes aromatic liquid by cooling with cold water. Since the water and oil collected in the condensation vessel do not mix, the oil is easily separated from the water.
When CO2 is used as a solvent in oil extraction, the components of the oil are not damaged by heat compared to the use of heated water or steam, and the extract is very close to the chemical structure of the plant. CO2 is a colorless, odorless gas that comes out when we exhale, necessary for plants to grow, and therefore does not harm the plant in the process. CO2 is liquefied by carbon dioxide pressure and pumped into the reservoir where the plant is. Due to the liquid properties of the gas, CO2 acts as a solvent in the natural plant and extracts other substances such as oil, pigment, resin from the plant. Thus, the essential oil dissolves in liquid CO2. When CO2 is returned to its natural pressure, it evaporates into a gaseous state and the essential oil decomposes.
EXTRACTION WITH SOLVENT(CO2 extraction, Maceration, Inflaurage)
Solvent oil separation method is the general name of CO2 extraction, maceration and inflammation methods. It is used for delicate aromas that contain very little essential oil, can not withstand the pressure and pressure from resinous herbs or steam distillation.
Food grade solvents such as hexane and ethanol are used to extract essential oils from the plant. Essential oils separated using a solvent give a better smell than all other methods, and the plant that interacts with the solvent gives a solid aromatic product like wax. When this solid product is mixed with alcohol, oil particles appear. The chemicals used remain in the oil and are not decomposed. These oils are used in the perfume industry or for aromatherapy.
Inflaurage is one of the oldest methods of separating essential oil using oil, but it is not used much today. The purified and odorless vegetable or animal fat is distributed on glass dishes and left to settle. Fresh flower petals or whole flowers are placed on the oil layer and pressed. Depending on the flower used, it is expected to settle for 1-2 days or 2 weeks. During this time, the scent of the flower passes into the oil. The dried leaves are renewed and the process is repeated until the oil reaches the desired saturation. Alcohol is used to separate the oil used and the botanical extract (the oil is used to make soap). When the alcohol evaporates from this mixture, the "essence" remains. If hot inflaurage is required depending on the plant, the same process is done by heating the oil.
Oils produced by maceration are also called infused oil. This method is better than distillation at trapping the essential oil of the plant because it can hold heavier and larger plant molecules. In this way, the valuable components of the plant are more trapped in the resulting product. Ideally, the plant should be mown and dry, because the slightest plant moisture will cause the oil to mold and microbial growth. Once the maceration process is complete, the oil that comes out will likely change color. The final product should be separated from the plant by filtering and placed in an airtight container to be stored cold and dry. When oil produced by maceration deteriorates, it becomes cloudy and can become moldy and smell bad. 5-10% of the oils produced by maceration are used as “active botanicals” in cosmetics. It can replace essential oil if used in large quantities.
This method is especially used for citrus fruits. The whole fruit is placed in a machine that breaks down the essential oil sacs under its peel and pressed to extract its juice and oil. Essential oil and pigments flow into the collecting area of the machine. Centrifugal force is applied to separate the resulting oil and juice from the remaining solids from the fruit. The oil is separated from the liquid layer and taken into another container.
Water distillation is used to extract oils from delicate flowers such as orange blossom and rose. The delicate flowers will stick together if they encounter steam during the distillation process, so the most effective separation method is to immerse the plant in pure boiling water. The water protects the separated oil from overheating. Condensed liquids cool and separate from each other. The remaining and sometimes fragrant water; It is called hydrolate, hydrosol, herbal water, essential water, flower water or herbal distilled water.