Are you looking for a powerful and reliable extraction setup to produce high-quality botanical extracts? Here you can find a comparison of common extraction techniques including ultrasonic extraction, supercritical CO2 extraction, ethanol extraction, maceration amongst others and their advantages as well as disadvantages.

Botanical Extraction using Ultrasound vs Alternative Techniques

Extraction of botanicals can be performed via various techniques. However, efficiency, extract yield and quality are influenced heavily by the extraction method and protocol used. Maceration, supercritical CO2 extraction, percolation and Soxhlet extraction are common extraction methods, which deliver often insufficient extraction results.
Ultrasound-based extraction is a sophisticated isolation technique, which excels traditional extraction methods in several points.
Ultrasound-based extraction using an ultrasonic probe is a highly efficacious method of extracting compounds from plants and other materials. Compared to other methods like maceration, CO2 extraction, percolation, and microwave extraction, ultrasonic probe-type extraction excels due to several advantages:

• Faster extraction: Ultrasonic probe-type extraction can extract compounds much faster than maceration and percolation. This is because ultrasonic waves create cavitation bubbles in the solvent, which create micro-shocks that help to break down cell walls and release the compounds more quickly.
• Higher yield: Ultrasonic probe-type extraction can extract a higher yield of compounds than maceration, CO2 extraction, and percolation. This is because the ultrasonic waves help to release more of the target compounds from the material being extracted.
• More efficient: Ultrasonic probe-type extraction is more efficient than maceration, CO2 extraction, percolation and Soxhlet extractors, as it requires less solvent to extract the same amount of compounds. This is because the ultrasonic waves help to increase the solubility of the target compounds in the solvent.
• Versatility: Ultrasonic probe-type extraction can be used to extract a wide range of compounds from various materials, including both hydrophilic and hydrophobic compounds. This means that ultrasound is excellent for the production of full-spectrum extracts, too.
• Low cost: Ultrasonic probe-type extraction is generally less expensive than CO2 extraction, percolation, maceration, and Soxhlet extraction, as it does not require high-pressure equipment or time-intense labour.
• Environmentally friendly: Ultrasonic probes allow for an environmentally friendly extraction, as it requires less solvent and energy compared to other methods, and produces less waste. Although sonication is compatible with any solvents, due to the high efficiency of ultrasonicators, toxic solvents can be mostly avoided. Ethanol, aqueous ethanol and water are excellent solvents for ultrasonic botanical extraction.

When compared to traditional botanical extraction techniques, ultrasonic probe-type extraction offers significant advantages, which explains the wide use of ultrasound extraction for numerous bioactive compounds from plants.

Extraction of High-Quality Extracts from Botanicals

For high-quality botanical extracts from not only the raw material (plant material) is essential, but also the extraction technique applied is crucial. Plant extracts are temperature-sensitive, which means they are degraded by heat. It is therefore crucial to choose a non-thermal extraction method.
The selection of the extraction solvent is another important factor, which influences the extract quality. Solvents such as hexane, methanol, butane and other harsh chemicals can contaminate the extract. Even though solvents are removed after extraction, trace amounts of toxic solvents can be found in the final extract. Water, alcohol, ethanol, glycerine or vegetable oils are safe, non-toxic solvents and approved by the FDA for consumption.

Step-by-Step Protocol of Botanical Extraction using an Ultrasonic Probe

How are bioactive compounds extracted from plants using probe-type ultrasonication? Below you can find a step-by-step instruction for the extraction of phytochemicals and bioactive compounds from plant material such as leaves, petals, fruiting body, stems, roots or rhizomes!

1. First, the plant material is ground or chopped into small pieces to increase the surface area for extraction.
2. The plant material is then mixed with a solvent (such as ethanol or water) to extract the polyphenols.
3. Probe-type ultrasonication is then used to aid in the extraction process by applying high-intensity, low-frequency ultrasound waves at approx. 20kHz to the mixture. This causes acoustic cavitation and a rapid vibration of the solvent, which promotes the disintegration and disruption of the plant cells and the release the bioactive substances such as polyphenols, flavonoids and vitamins.
4. The mixture is then filtered to separate the solid plant material from the liquid containing the extracted bioactive compounds.
5. The liquid is then evaporated or subjected to further processing to remove the solvent and concentrate the bioactive molecules.
6. The final product is a bioactive-rich extract that can be used in various applications such as dietary supplements, functional foods, and cosmetics.

Note: This is an overview of the process and the specific conditions (solvent, ratio of plant material to solvent, time of extraction, ultrasonication power, etc.) may vary depending on the plant source and desired bioactive substance content.

How Does Ultrasonic Extraction Work?

Ultrasonic extraction is based on the working principle of ultrasonic acoustic cavitation and is a purely mechanical treatment. Similar to a high-shear mixer, an ultrasonicator only creates mechanical shear forces in the process medium. Ultrasonic extraction itself is non-thermal, chemical-free extraction technique.
What is Acoustic Cavitation? – Acoustic or ultrasonic cavitation occurs when high-power, low-frequency ultrasound waves are coupled into a slurry consisting of botanical material in a liquid (solvent). High-power ultrasonic waves are coupled via a probe-type ultrasonic processor into the botanical slurry. Highly energetic ultrasound waves travel through the liquid creating alternating high-pressure / low-pressure cycles, which results in the phenomenon of acoustic cavitation. Acoustic or ultrasonic cavitation leads locally to extreme conditions such as very high pressure differentials and high shear forces. When cavitation bubbles implode on the surface of solids (such as particles, plant cells, tissues etc.), micro-jets and inter-particlular collision generate effects such as particle breakdown, sonoporation (the perforation of cell walls and cell membranes) and cell disruption. Additionally, the implosion of cavitation bubbles in liquid media creates turbulences and agitation, which promotes the mass transfer between the cell interior and the surrounding solvent. Ultrasonic irradiation is a highly efficient way to enhance mass transfer processes, since sonication results in cavitation and its related mechanisms such as micros-movement by liquid jets, compression and decompression in the material with the subsequent disruption of cell walls.
Depending on the raw material, the ultrasonic extraction process might require high intensities, e.g. to break stiff plant cells or material with a high cellulose amount. Probe-type ultrasonicators can generate very high amplitudes, which is necessary to generate impactful cavitation. Hielscher Ultrasonic manufactures high-performance ultrasonic extractors, which can easily create amplitudes of 200µm in continuous 24/7 operation. For even higher amplitudes, Hielscher offers specified high-amplitude sonotrodes (probes).
Pressurizable ultrasonic reactors and flow cells are used to intensify the cavitation. With increasing pressures, cavitation and cavitational shear forces become more destructive and improve thereby the ultrasonic extraction effects.

Extract Phyto-Chemicals and Bioactive Compounds with Sonication

Ultrasonic extraction is used to release and isolate a wide variety of bioactive compounds (so-called phyto-chemicals) from botanicals.
The list below gives you a small overview over ultrasonically extracted phyto-chemicals:

• CBD and other Cannabinoids from Cannabis and Hemp
• Terpenes
• Ginger
• Rosemary
• Capsaicin from Chillies
• Caffeine from Coffee Beans
• Astaxanthin from Algae
• Allicin from Garlic
• Catechins (EGEC) from Tea
• Ellagitannins from Pomegranate
• Ayurvedic Herbal Extracts
• Nicotine from Tobacco
• Essential Oils
• Pectins from Citrus Fruit Peels

Solvents for Ultrasonic Extraction

Ultrasonic extraction is compatible with almost any solvent. Most commonly, ethanol, water, ethanol/water mix, glycerine, and vegetable oils are used for the extraction of bioactive compounds from botanicals as these solvents are considered as safe for consumption and are easy-to-use.
Read more about solvents used for ultrasonic extraction!

The Advantages of Ultrasonic Ethanol Extraction

Ethanol is one of the most commonly used solvents with ultrasonic extraction due to its safety (FDA-approved for consumption), its efficacy, and its wide ranging solvency. Ultrasonic ethanol extraction outshines other solvents and other extraction technologies with cost-efficiency, linear scalability, simplicity, and safety.
The superior efficacy of ethanol as solvent is linked to its chemical composition of a hydrocarbon tail and a single hydroxyl group. This chemical composition allows ethanol to dissolve and extract a very wide spectrum of substances, from polyphenols, flavonoids, terpenes, cannabinoids, and lipids (oils).
For instance, ultrasonic ethanol extraction of cannabinoids does not require winterization (dewaxing), a step required with other extraction methods such as CO2 extraction to remove the waxes.

Ethanol extraction exhibits different effects depending on the ethanol temperature. Heated ethanol is often used to produce full-spectrum extracts, which are valued for their entourage effect. On the other hand, ice-cold ethanol is preferably used to produce herbal or cannabis distillates. The extraction in ice-cold ethanol does not require subsequent filtration. Since ultrasonic extraction is a non-thermal treatment, it can be used with hot/warm or cooled/ice-cold ethanol. Jacketed ultrasonic reactors help to maintain the desired processing temperature during the treatment. The digital control and smart software of the ultrasonicator monitors the processing temperature via a pluggable temperature sensors and can be programmed to stop or pause the extraction treatment when the temperature of the medium gets out of a certain range.

Buy the Most Efficient Ultrasonic Extraction Equipment!

Hielscher Ultrasonics’ high-performance extraction systems are available at any scale from small lab size, mid-size pilot scale to fully-industrial production of several tons per hour. Depending on the throughput, Hielscher ultrasonic extractors can be used in batch or continuous inline mode. The choice of solvent is up to you, as Hielscher ultrasonicators can be used in combination with any solvent. All ultrasonic extraction devices are simple and safe to operate. In accordance on your raw material, process capacities and output target, Hielscher offers you the most suitable ultrasonicator.
Ultrasonic extraction processes are influenced by raw material, solvent, and throughput. Various accessories such as sonotrodes (probes) of various sizes and shapes, booster horns, flow cells with various volumes and geometries, pluggable temperature and pressure sensors and many other gadgets are available to assemble the ideal ultrasonic setup for your extraction process.
Process control is crucial in order to obtain reproducible outcome. Therefore, all digital models are equipped with intelligent software, which allows you to adjust, monitor, and revise extraction parameters. Due to the precise control over amplitude, sonication time and duty cycles, optimum process results such as superior yield and highest extract quality can be achieved. The automatic data recording of the sonication process are the bases for process standardization and reproducibility / repeatability, which are required for Good Manufacturing Practices (GMP).

The table below gives you an indication of the approximate processing capacity of our ultrasonicators:

Literature / References