Techniques for the Extraction of Essential Oils
Sources of natural essential oil
Essential oils are used in a wide range of consumer products, including detergents, soaps, toilet products, cosmetics, pharmaceuticals, perfumes, confectionery, soft drinks, distilled alcoholic beverages (stiff drinks), and insecticides.
Essential oils are also used in aromatherapy. The quantity of essential oils and fragrances that are produced and used throughout the globe is growing at a breakneck pace.
The technology used in production is a crucial component in achieving improvements in the total yield and the quality of essential oil.
The age-old processes used in producing essential oils have a great deal of cultural weight and are, to this day, practiced in several countries worldwide. The most typical and time-tested processes are distillation with water, distillation with water and steam, steam distillation, maceration, and cohobating. Enfleurage is another technique that is sometimes utilized.
When the oil output from distillation is low, maceration might be a helpful alternative. Powdered almonds, rose petals, and rose blossoms are all appropriate candidates for the distillation process. On the other hand, costly, fragile, and thermally unstable materials like jasmine, tuberose, and hyacinth are better suited for the solvent extraction approach. The manufacture of citronella oil from plant material is most often done by distilling water since it is the most efficient way.
Natural derivations of essential oils and their sources
Essential oils are typically extracted from one or more plant parts, including flowers (such as rose, jasmine, carnation, clove, mimosa, rosemary, and lavender), leaves (such as mint, Ocimum spp., lemongrass, jamrosa), leaves and stems (such as geranium, patchouli, petitgrain, verbena, cinnamon), bark (such as cinnamon, cassia, canella), wood (such as cedar, sandal, pine), roots (
Techniques for the Extraction of Essential Oils
The essential oils business has evolved language to differentiate between three forms of hydrodistillation: water distillation, water, and steam distillation, and direct steam distillation. These three methods are referred to together as water distillation.
These words have gained common vocabulary in the field of essential oils since Von Rechenberg first presented them. In the distillation of two-phase systems, the theoretical concerns that apply to one approach also apply to the other two ways. The primary distinctions are the processes used while working with the material.
Certain volatile oils cannot be distilled without first decomposing. As a result, they are often acquired by expression (like lemon oil and orange oil) or through other mechanical processes. Rolling the fruit over a trough lined with sharp projections that are long enough to penetrate the epidermis and pierce the oil glands within the peel’s outer portion is the standard technique used in some nations to puncture the oil glands to extract citrus oil. In other words, the epidermis and the oil glands are pierced (ecuelle method). The fat is removed from the glands of the fruit through a pressing action.
Centrifugation is used to separate the oil-water emulsion produced as a consequence. In one variant of this method, the fruit’s peel is removed before the oil is extracted.
The extraction of the oil follows this.
The volatile oil concentration of fresh plant parts (flower petals, for example) is often so low that oil extraction using the above procedures is not commercially viable. In these situations, an odorless, tasteless, and flavorless fixed oil or fat is distributed evenly over the surface of glass plates in a thin layer. After placing the flower petals on the fat for a few hours, the oil petals are repeatedly removed, adding a fresh layer of flower petals. This process is done many times. After the fat has been taken in the maximum amount of aroma, the oil may be extracted using alcohol. This technique, which was initially called enfleurage, was used widely in manufacturing perfumes and pomades in the past.
Extraction, with the assistance of volatile solvents like petroleum ether and hexane, is the method of choice in the perfume business for most contemporary essential oil manufacturing. As a result, extracted oils have a more natural odor that is unmatched by distilled oils, which may have undergone chemical alteration due to the high temperature. One of the primary advantages of extraction over distillation is maintaining a consistent temperature throughout the process, typically 50 degrees Celsius.
The perfume business places a significant premium on this characteristic; the time-tested distillation technique is far more cost-effective than the extraction procedure.
The process of distilling volatile oils without air is known as destructive distillation. When the wood or resin of plants belonging to the Pinaceae or Cupressaceae families is heated in the absence of air, decomposition occurs, and various volatile chemicals are driven out. The material that was left behind was charcoal. In most cases, the condensed volatile matter will separate into two layers: an aqueous coating that contains wood Naptha (methyl alcohol) and pyroligneous acid (crude acetic) and a tarry liquid that can take the form of pine tar, juniper tar, or other tars, depending on the type of wood that was used. This dry distillation is often carried out in retorts, and if the wood is chipped or coarsely powdered before the heat is applied, the yield typically amounts to around 10% of the total weight of the wood utilized.
Extraction of Essential Oils Using Solid Fat at Room Temperature (Enfleurage)
The time-honored method of enfleurage, which has been handed down from generation to generation and improved upon over the years, continues to be used despite developing more recent extraction techniques using volatile solvents.
Despite the passage of generations, it continues to perform a significant function. The only method used to do enfleurage on an extensive basis nowadays is the vicinity of Grasse, France, with the probable exception of a few sporadic cases in India.
The procedure has not evolved much over time.
The basic ideas of enfleurage are easy to understand. A few blooms (e.g., tuberose and jasmine) Even after plucking, the physiological processes of developing and giving out scent will continue.
Every single jasmine and tuberose blossom is analogous to, so to say, a little factory that is continuously releasing minute amounts of perfume. A large absorption capacity is possessed by fat, and when it is brought in.
When in touch with fragrant flowers, one readily takes up the scent of the flowers. This guiding concept, in a systematic, is applied on a big scale, it forms enfleurage. During the whole harvest, which typically lasts eight to ten weeks, batches of newly plucked flowers are scattered throughout the surface of a bed.
Fat basis (corps) is mainly produced and aged there (for 24 hours in the case of jasmine and longer in the case of the example of tuberose); the old blooms were replaced with new ones. After the harvest is complete, the fat, known as floral oil, has soaked the material since it was not refreshed throughout the procedure. After that, the fat is removed from the seeds.
The alcohol was to the fat, which was then separated.
The effectiveness of the enfleurage technique relies heavily on the fat foundation’s quality.
Employed. When it comes to the preparation of the corps, the utmost attention is required. This must be the case.
They smelled of nothing and had the right consistency. If the corps is not soft enough, the flowers will not have enough contact with the fat, reducing the fat's capacity for absorption and leading to a lower-than-normal yield of Oil extracted from flowers. If it is overly soft, on the other hand, it will tend to smother the blooms and the ones that are spent.
Will stick; even after removal, the blooms will still have to stick fat on them, resulting in significant damage.
Decrease in size and number of corps. Therefore, the uniformity of the company has to be of a kind that allows it to provide a surface with a medium degree of hardness, from which the spent blossoms may be readily removed. How the enfleurage process occurs in cold cellars, and every producer is responsible for preparing the corps.
By the average temperature that prevailed in the basements during the months dedicated to the flower harvest.
Many years of practical experience have shown that a combination consisting of one part highly refined tallow and nine parts highly sophisticated fat.
And two parts of lard are an excellent choice for the enfleurage technique. This composition guarantees an appropriate
We are maintaining the uniformity of the corps while also having a high absorption capacity. The fatty mass, as a result, the finished product is completely devoid of water, white, silky smooth, entirely consistent in consistency, and nearly odorless.
Odorless. When making these products, some producers additionally use trace amounts of orange flower or rose water.
They are making preparations for the corps. It seems that this is done to adhere to tradition. These additions help to some degree.
You may tone down the smell of the completed product by giving it a hint of rose or orange blossom.
Enfleurage and Defleurage
Each enfleurage structure is outfitted with thousands of what are known as chassis, which function as
Containers for temporarily housing the obese corpses while the operation is carried out. The components that make up a chassis are a rectangular wooden
Frame. A glass plate is held inside the frame, and the fat corps is affixed with a sticker on both sides of the container.
During the beginning of the enfleurage procedure, a spatula is used. The chassis, when stacked one on top of the other, looks like this:
Create airtight compartments by coating each glass plate’s top and bottom sides with a layer of fat and then placing them in a container.
During the harvest, the newly harvested flowers are delivered each morning, and after being cleansed of any debris, they are arranged.
Hand-scattered contaminants, like leaves and stalks, are placed on top of the fat layer in each glass.
Plate. Never use blossoms exposed to moisture from dew or rain since even the slightest amount may cause mold to form.
The corpses smelled putrid. After that, the chassis is stacked in the basements for at least twenty-four hours, if not longer.
It is based on the species of the flowers. These latter lie in direct touch with a single layer of fat (the bottom layer).
The chassis absorbs only the volatile aroma exhaled by the flowers.
Essential oils may be extracted using contemporary (non-traditional) methods as well.
The traditional ways of extracting essential oils have been explored, and it has been found that these procedures are the ones used commercially. However, with the advancement of technology, new methods have been developed. These new methods may not be widely used for the commercial production of essential oils, but they are considered valuable in certain circumstances. These circumstances include the production of expensive essential oils in their natural state without any alteration of their thermosensitive components or the extraction of essential oils for use in micro-analysis.
Conclusions
The nations of South East Asia have inadequate farming techniques for medicinal and aromatic plants (MAPs), as well as unscientific and indiscriminate harvesting methods from the wild, two of the most significant factors preventing the sustainable economic use of MAPs.
Poor postharvest and post-gathering practices lead to poor quality raw material, lack of research for the development of high-yielding varieties of MAPs, lack of research for the development of high-yielding assortments of MAPs, inferior propagation methods, inefficient processing techniques, poor quality control procedures, lack of research on the process and product development, difficulty in marketing, non-availability of trained personnel, lack of facilities and tools to fabricate equipment locally, and finally lack of access to the latest Because of this, it is necessary for the many institutions and organizations located in the area to work together and coordinate their efforts to build MAPs for sustainable economic use.
How well we add value to MAP bioresources is directly proportional to the method by which MAPs are extracted. When it comes to essential oils, removing them affects the external and interior makeup. Even if the analytical findings are within permissible limits, the batch may be rejected based only on its outward appearance, leading to wasted time and resources. In addition, expert perfumers from throughout the world assess essential oils for their olfactory attributes, and the results of these evaluations take precedence over analytical findings. When extracting medicinal plants using processes that are not standardized, it is possible for there to be variations in the chemical components of the resulting extracts.
