The Working Principle And Advantages Of Ultrasonic Extraction Technology

Ultrasonic extraction technology is the preferred technique for isolating bioactive compounds from plants. Ultrasound refers to those mechanical sound waves with frequencies above 20 kHz but less than 10 MHz. Ultrasonic extraction typically uses a smaller frequency range (16 kHz-100 kHz), as higher frequencies can lead to excess energy, which can lead to the degradation of active components in plant structures.

Sonication enables complete extraction, resulting in high extraction yields in very short extraction times. As an efficient extraction method, ultrasonic extraction saves both cost and time while yielding high-quality extracts for use in food, supplements, and pharmaceuticals.

01 How it works

Ultrasonic extraction is based on the working principle of ultrasonic cavitation and is a purely mechanical treatment. Similar to high shear mixers, sonotrodes generate mechanical shear forces only in the process medium. Ultrasonic extraction itself is a non-thermal, chemical-free extraction technique.

Ultrasonic cavitation is sonic or ultrasonic cavitation that occurs at high power, based on repeated high and low pressure cycles. The alternating high and low pressure cycles of sonication 20,000 times per second create intense shear forces and liquid jets. This extreme stress overcomes the selectivity of the membrane, perforates and disrupts the cell wall, and results in high-quality transport between the inner cell and the surrounding solvent. With ultrasonic extraction, higher yields and shorter extraction times can be achieved. Since ultrasonic extraction is a repeatable process, extraction results can be repeated for standardized extraction quality.

Ultrasonic cavitation can locally lead to extreme conditions such as very high differential pressures and high shear forces. When cavitation bubbles burst onto the surface of solids (e.g. particles, plant cells, tissues, etc.), micro-jets and inter-particle collisions can produce effects such as particle rupture, sonoporation (perforation of cell walls and membranes), and cellularity. Furthermore, the bursting of cavitation bubbles in liquid media creates turbulence and agitation, which facilitates mass transfer between the interior of the cell and the surrounding solvent. Ultrasound radiation is an efficient way to enhance mass transfer processes, as ultrasound induces cavitation and its associated mechanisms, such as micromotion induced by liquid jets, compression and decompression in materials, and subsequent cell wall disruption.

02Advantages

Ultrasonic extraction can reduce the amount of solvent and make the amount of solvent more gentle. This means that ultrasonic extraction improves extraction yields and results in healthier extracts. This is due to its characteristic of operating at low temperature, which can not only reduce heat loss due to temperature factors, but also avoid vaporization of substances due to low boiling points and maintain biologically active substances. Ultrasonic extraction is a simple, safe and precisely controllable application. As a non-thermal extraction method, sonication can be performed at low temperature, thus avoiding the degradation of thermally sensitive, thermally unstable substances. Ultrasonic extraction is also able to greatly reduce production time, as the traveling ultrasound disrupts the cell walls, thereby reducing the transfer time of active ingredients from the plant material to the solvent.

03 The effect of ultrasonic extraction

Ultrasonic Cell Disruption and Increased Mass Transfer Ultrasound can assist the extraction process by cell disruption and enhanced mass transfer in the boundary layer around the solid matrix. As a perforation of cell walls and membranes, ultrasound can enhance the permeability of cell walls and membranes, often an intermediate step before cells are completely destroyed by ultrasound.

Mechanical effects of ultrasound-induced cavitation, such as heat and pressure differences, shock waves, shear forces, liquid jets, and microfluidics, enhance solvent penetration into the interior of cells and improve mass transfer between cells and solvents, allowing The intercellular material is transferred to the solvent.

04Summary

Ultrasonic extraction technology uses the cavitation produced by ultrasonic waves to extract active ingredients from plants. Compared with conventional extraction methods, ultrasound-assisted extraction methods become more attractive due to their various advantages, such as low energy consumption, short extraction times, less destruction of active compounds, and high extraction yields.