Search
×
News Products

Common Botanical Extraction Methods


At present, the commonly used botanical extraction methods include solvent extraction, ultrasonic extraction, microwave extraction, and enzyme extraction. In contrast, supercritical fluid extraction and microwave-assisted extraction are widely used as new extraction techniques.


Solvent extraction


Solvents are used to extract effective ingredients from solid raw materials, and the solvents used must have the characteristics of being miscible with the extracted solute. After the plant material is crushed, it is put into a suitable container, and several times the amount of solvent is added. The extraction can be carried out by dipping, percolating, decocting, refluxing, and continuous extraction. In the extraction process of the solvent extraction method, the concentration of the solvent, the ratio of material to liquid, the extraction temperature, and the extraction time will directly affect the extraction rate of the effective ingredients.


Ultrasonic extraction


The intense vibration and cavitation effect produced by ultrasonic waves accelerate the release, diffusion, and dissolution of substances in plant cells into the solvent while keeping the structure and biological activity of the extracted essences unchanged. The principle of ultrasonic extraction is mainly a physical process, and it is a relatively new extraction method that has gradually received attention in recent years. For most components, the ultrasonic extraction method can significantly shorten the extraction time compared to conventional solvent extraction. It consumes less solvent and has a higher leaching rate, resulting in higher extraction efficiency. In the ultrasonic extraction process, the selection and concentration of the solvent, the ratio of material to liquid, the extraction temperature, and the extraction time will directly affect the extraction rate. Compared with the commonly used organic solvent extraction method, the ultrasonic extraction method has a high extraction rate, fast speed, and high efficiency and extracts at room temperature without heating, and saves energy.


Supercritical fluid extraction method 


SFECO2 is generally used as an extractant. The principle of supercritical fluid extraction is to use the unique dissolving power of supercritical fluid, the solubility of substances in supercritical fluids, and the sensitivity of substances to changes in pressure and temperature. The substances dissolved in the critical liquid are separated to achieve the purpose of separation and purification. It has both rectification and extraction functions. The obtained active ingredient is not easy to be inactivated, has high quality, and the extraction and separation process is completed simultaneously. This green and environmentally-friendly high-tech separation technology is particularly suitable for separating and purifying unstable natural products and physiologically active substances.


Microwave-assisted extraction method 


MAEMicrowave-assisted extraction is a method of selectively extracting target components in materials using microwave heating characteristics. By adjusting the parameters of the microwave, the target components can be effectively heated to facilitate the extraction and separation of the target components. The principle of the microwave-assisted extraction method for extracting plants is that the plant sample absorbs a lot of energy in the microwave field. In contrast, the surrounding solvent absorbs less, resulting in thermal stress inside the cell. Plant cells rupture due to internal thermal stress. The substances inside the cells directly contact the relatively cold extraction solvent, which accelerates the transfer of the target product from the cell interior to the extraction solvent, thereby strengthening the extraction process. The principle of microwave-assisted extraction technology is the same as soaking and filtering. It also uses heat energy, but extracting plant extracts is much faster than traditional methods. It reduces the extraction time and avoids the destruction and degradation of valuable plant extracts. The microwave-assisted extraction method has become a powerful tool for extracting natural plant active ingredients with its fast extraction speed and good extract quality. However, the microwave-assisted extraction method requires selective internal heating and processed material to have good water absorption. In other words, the position where the product is to be separated is located easy to absorb water. Otherwise, the cell will not be able to absorb enough microwaves to break itself, and the product will not be released quickly. For liquid extraction systems, the solvent substance must be polar, and non-polar solvents are not sensitive to the effects of microwaves.


Microwave and ultrasonic synergistic extraction method


Microwave is non-ionizing electromagnetic radiation. The polar molecules of the irradiated substance quickly turn and align in the microwave electromagnetic field, which causes tearing and mutual friction to generate heat. This can ensure the rapid transmission and full utilization of energy and has the advantages of high efficiency, energy-saving, and no industrial pollution. However, the microwave penetration depth is limited (in the same order of magnitude as its wavelength), and its mass transfer function in the enhanced extraction process is not significant. Ultrasound is a high-frequency mechanical wave with turbulence, perturbation, interface, and energy-gathering effects. Still, the thermal effect produced by ultrasound is not significant, and it is limited to a very small area around the cavitation bubble. The synergistic effect of combining the two is conducive to breaking wall components. That is, a kind of high-efficiency, low-cost, non-polluting biologically active substance can be obtained through microwave-ultrasonic synergistic and enhanced extraction technology.


Enzyme extraction method


The cell walls of natural plants are composed of cellulose, and the effective components of plants are often wrapped in the cell walls. Enzyme extraction is a method that uses cellulose, pectinase, protease, etc. (mainly cellulose) to destroy the cell wall of plants to promote the maximum dissolution and separation of plant active ingredients. In the extraction process of enzyme extraction method, the selection of enzyme, enzyme concentration, pH value, enzymolysis temperature and enzymolysis time will all affect the extraction rate of plant extracts.


Related Botanical Extract News