Benefits of microwave extraction
The term “extraction” means a method of extracting a substance from a solution using a solvent. In this case, the solvent is the intracellular fluid contained in the raw material. Any raw material containing at least 50% liquid and essential oils, which are highly concentrated plant extract, can be subjected to extraction.
More than 3000 species of essential oil plants are known. Essential oils can be diffusely distributed in the cell sap, but more often they accumulate in special formations – glands, secretory cells, secretory tubules and receptacles. These volatile natural aromas are found in seeds, bark, stems, roots, flowers and other parts of plants. The content of essential oils in a plant ranges from hundredths of a percent to 5%.
There are several ways to obtain plant extracts, which have both their advantages and disadvantages, associated with the laboriousness of the process or with the need to purify the essential oil from the solvent, which is a dangerous chemical reagent.
The advent of microwave technology avoids all the inconveniences of previous methods for extracting essential oils and opens up new possibilities for obtaining an environmentally friendly product.
Under the influence of electromagnetic radiation, dipole water molecules in the vacuoles of the plant begin to rotate in accordance with the law of changes in the electric field during the period of the operating frequency. Molecular friction leads to the heating of water in the vacuoles of the plant, the rupture of tissue fibers, the formation of steam and the removal of the extraction products with it into the working volume.
Our experiments have confirmed that the electric field penetrates into the deep layers of the raw material until complete absorption of microwave energy. This is due to the fact that as a result of polarization saturation in the layers closer to the radiation source, only a limited fraction of the energy is absorbed and the radiation penetrates into the center of the loaded raw material volume. So almost 100% recovery of all valuable substances occurs.
What are the stages of raw materials during microwave extraction:
- High temperatures affect the raw material → the release of volatile fractions begins due to the destruction of the plant’s cellular structure.
- The mixture of essential oil and vapor molecules is lifted up the tube through the cooling tank.
- The steam begins to take on a liquid state of aggregation.
- The liquid collected in a special compartment is a mixture of essential oil and water.
- It separates easily into layers due to the difference in the density of water and oil.
- A by-product – hydrolat – flower water saturated with a certain amount of aromatic substances.
Laboratory studies and calculations have shown that microwave extraction from freshly harvested raw materials without mechanical treatment, solvents and water addition, in comparison with traditional methods, allows:
- to increase the yield of recovered substances by 2–3 times;
- reduce the duration of the process by almost 10 times;
- to reduce specific energy consumption by more than 50%;
- get higher quality products;
- ensure the environmental friendliness of the process.
Essential oil raw materials are widely used in many sectors of the national economy: perfumery, food, soap-making, cosmetic industry and other industries.
The use of essential oil raw materials in medicine is mainly associated with the presence of substances in essential oils,
with a wide range of therapeutic properties.
For microwave extraction, our company produces an industrial microwave installation “Samun”. You can read more about the furnace, its capabilities, technical characteristics here >>>