Principles And Characteristics Of Ultrasonic Extraction

Ultrasonic extraction utilizes the mechanical effects, cavitation effects and thermal effects of ultrasonic waves to extract biological active components by increasing the velocity of the medium molecules and increasing the penetrating power of the medium.

Mechanical effect

The propagation of ultrasonic waves in the medium can cause the medium particles to vibrate in their propagation space, thereby enhancing the diffusion and propagation of the medium, which is the mechanical effect of the ultrasonic waves. Ultrasonic waves generate a kind of radiation pressure in the process of propagation, which propagates along the direction of sound waves, which has a strong destructive effect on the material, which can deform the cell tissue and denature the plant protein. At the same time, it can also give the medium and the suspension different accelerations. And the velocity of the medium molecules is much faster than the velocity of the suspension molecules. Thereby, friction is generated between the two, which can depolymerize the biomolecules, so that the active components on the cell wall dissolve in the solvent more quickly.

Cavitation effect

Usually, some microbubbles are dissolved more or less inside the medium. These bubbles vibrate under the action of ultrasonic waves. When the sound pressure reaches a certain value, the bubbles increase due to the directed diffusion (rectieddiffvsion), forming a resonant cavity. Then suddenly closed, this is the cavitation effect of the ultrasound. When the bubble is closed, it generates pressure of several thousand atmospheres around it, forming a micro-shock, which can cause the plant cell wall and the whole organism to rupture, and the entire rupture process is completed in an instant, which is favorable for the dissolution of the active ingredient.

Thermal effect 

Like other physical waves, the propagation of ultrasonic waves in a medium is also an energy propagation and diffusion process. That is, during the propagation of ultrasonic waves, the acoustic energy is continuously absorbed by the particles of the medium, and the energy absorbed by the medium is all or large. Partial conversion to thermal energy leads to an increase in the temperature of the medium itself and the medicinal tissue, which increases the dissolution rate of the active ingredient of the drug. Since the increase in the internal temperature of the drug tissue caused by the absorption of the acoustic energy is instantaneous, the biological activity of the extracted component can be kept constant.

In addition, ultrasound can also produce many secondary effects, such as emulsification, diffusion, crushing, chemical effects, etc. These effects also promote the dissolution of active ingredients in plants, promote the entry of active ingredients into the medium, and fully mix the medium to accelerate The extraction process is carried out and the extraction rate of the active ingredient of the drug is improved.

Characteristics of ultrasonic extraction

Ultrasonic extraction does not require heating, which avoids the adverse effects of traditional Chinese medicine boiling and long-time heating on the active ingredients, and is suitable for the extraction of heat-sensitive substances. At the same time, it saves energy because it does not require heating.

Ultrasonic extraction improves the extraction rate of active ingredients of the drug, saves raw materials, facilitates the full utilization of traditional Chinese medicine resources, and improves economic benefits.

The solvent is used in a small amount, saving solvent.

Ultrasonic extraction is a physical process in which no chemical reaction takes place during the entire leaching process and does not affect the physiological activity of most of the active ingredients of the drug.

The extract has a high content of active ingredients and is advantageous for further purification.