Hielscher Ultrasound Technology

Most Efficient Extraction Method for Botanical Extracts

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.

What are Botanical Extracts?

Botanicals such as leaves, petals, flowers, stems, roots, and bark contain potent bioactive compounds (phyto-chemicals), which are used in foods and beverages, dietary supplements, therapeutics and pharmaceuticals as well as in cosmetic products. Prominent examples of botanical extracts are antioxidants, vitamins (e.g. vitamin A, C, E, K; B vitamins), proteins (e.g. hemp, soy), polyphenols, flavonoids, terpenes, cannabinoids (e.g. CBD, CBG, THC), oligosaccharides, and lipids (e.g. omega-3s from flax seeds or hemp seeds).
Antioxidants act as a powerful defense mechanism that prevents the body’s cells against damage to from aging, stress, inflammation and disease. Research also shows that antioxidants can contribute as immun system enhancer and exhibit anti-cancer properties. Furthermore, antioxidants prevents the oxidation of products and extends thereby their stability and shelf-life. Therefore, antioxidants are added to many foods and drinks, nutritional supplements, therapeutics and cosmetic products. Very prominent examples of antioxidants are vitamin E (α-tocopherol), vitamin C (ascorbic acid), beta-carotene and glutathione.
Antioxidants and other bioactive compounds can be either extracted from natural materials such as botanicals or algae or artificially synthesised. Bioactive compounds, which are extracted from a natural source, show a higher bioavailability, bioaccessibility and thereby increased potency. Therefore, in high-quality supplements naturally extracted phyto-chemicals are used.

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.

UP400St - powerful ultrasonic extractor. (Click to enlarge!)

Botanical extraction with the ultrasonicator UP400St

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Ultrasonic Extraction Maceration CO2 Extraction Soxhlet Percolation
Solvent compatible with almost any solvent water, aqueous and non-aqueous solvents organic solvents water, aqueous and non-aqueous solvents CO2
Temperature non-thermal extraction,
precise temperature control
ambient under heat ambient temperature,
occasionally heat is applied
above the critical
temperature of 31°C
Pressure both, atmospheric or
elevated pressure possible
atmospheric atmospheric atmospheric very high pressures
(above the critical pressure of 74 bar)
Processing Time rapid very slow slow very slow moderate
Amount of Solvent low,

high solid load of plant material
in the solvent, especially when a flow cell
setup is used
large moderate large large amounts of
supercritical CO2
Polarity of Natural Extract dependent on solvent;
to extract non-polar and polar
compounds, a dual-stage extraction
using two solvents is recommended
dependent on solvent dependent on solvent dependent on solvent dependent on pressure
(under higher pressures more polar)
Flexibility / Scalability for batch and inline extraction,
linear scalability
batch extraction only,
limited scalability
batch extraction only,
limited scalability
batch extraction only,
limited scalability
batch extraction only,
limited linear scalability,
very expensive
Advantages of Ultrasonic Extraction at a Glance:

  • High yields
  • Superior Quality
  • Full Spectrum Extracts
  • Rapid Process
  • Compatible with Any Solvent
  • Easy and Safe to Operate
  • Linear Scalability
  • Environmental-Friendly
  • Fast RoI

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, The UIP4000hdT is a 4000 watts powerful ultrasonic inline disperser.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:

Solvents to Use 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’s temperature. Nicotine extraction from dried tobacco leaves with UP400St ultrasonicatorHeated 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.
Hielscher's industrial processors of the hdT series can be comfortable and user-friendly operated via browser remote control.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:

Batch Volume Flow Rate Recommended Devices
1 to 500mL 10 to 200mL/min UP100H
10 to 2000mL 20 to 400mL/min UP200Ht, UP400St
0.1 to 20L 0.2 to 4L/min UIP2000hdT
10 to 100L 2 to 10L/min UIP4000hdT
n.a. 10 to 100L/min UIP16000
n.a. larger cluster of UIP16000

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Ultrasonic processor UIP2000hdT (2kW) with stirred batch reactor

Ultrasonic homogenizer UIP2000hdT (2kW) with continuously stirred batch reactor

Literature / References



Random Facts Worth Knowing

How does CO2 work as solvent?

CO2 heated to above 90 degrees Fahrenheit and 1000 pounds per square inch pressure is considered supercritical. Supercritical CO2 will act as a solvent that dissolves oils.

What is the Winterization of Cannabis Extracts?

In order to winterize a crude extract, the crude cannabis extract is mixed with ethanol. Afterwards, the solution is then placed in a freezer to chill. The cold allows for the separation of compounds by differences in their melting and precipitation points. In the cooling process, the fats and waxes with higher melting points will precipitate out and can then be removed by filtration, centrifugation, decantation, or other separation processes. Finally, the ethanol must be removed from the solution. This is achieved by boiling. Ethanol boils off at 78.5°C atmospheric pressure. Eventually, a pure liquid cannabis oil extract is obtained.

The Nutritional Benefits of Antioxidants

Antioxidants act as a powerful defense mechanism that prevents the body’s cells against damage to from aging, stress, inflammation and disease. Research also shows that antioxidants can contribute as immun system enhancer and exhibit anti-cancer properties.
Antioxidants are molecules that capture free radicals. Free radicals and other reactive oxygen species (ROS) are derived either from regular, essential metabolic processes in the human body or from external sources such as exposure to X-rays, ozone, cigarette smoking, air pollutants, and toxic chemicals. Free radicals are produced in many chemical chain reactions in the body as result of aerobic metabolism. The formation and exposure to free radicals is part of many metabolic processes and cannot be avoided. A healthy body can cope with the normal formation of free radicals, scavenges them and turns them into harmless molecules. However, in stressful events or under harmful environmental conditions, the burden of free radicals rises and contributes to inflammation and ageing. Good, healthy nutrition provides antioxidants, which disarm oxidative free radicals.

There are two categories of antioxidants that can be distinguished, the antioxidant enzymes (e.g. superoxide dismutases, catalase, glutathione peroxidase), and antioxidant nutrients, which include vitamins, minerals and various phytochemicals. A few classes of anti-oxidative nutrients are listed below:

  • vitamin E (α-tocopherol), vitamin C (ascorbic acid), beta-carotene
  • glutathione, ubiquinol, and uric acid
  • selenium
  • flavonoids (polyphenolic pigments)

Vitamin C, uric acid, bilirubin, albumin, and thiols are hydrophilic, radical-scavenging antioxidants, while vitamin E and ubiquinol are lipophilic radical-scavenging antioxidants.
The antioxidants‘ potency in food is measured as ORAC value (Oxygen Radical Absobance Capacity). According to the USDA, the following foods has the highest ORAC values and thereby the best antioxidative potency:

    • Prunes: 5770
    • Raisins: 2830
    • Blueberries: 2400

Fruits and vegetables are rich in antioxidants. Ultrasonic extraction is a highly efficient method to release and isolate bioactive compounds such as antioxidants, vitamins and polyphenols from fruits and vegetables.

  • Blackberries: 2036
  • Kale: 1770
  • Strawberries: 1540
  • Spinach: 1260
  • Raspberries: 1220
  • Brussels sprouts: 980
  • Plums: 949
  • Alfalfa sprouts: 930
  • Broccoli flowers: 890
  • Beets: 840
  • Oranges: 750
  • Red grapes: 739
  • Red bell pepper: 710
  • Cherries: 670
  • Kiwi fruit: 602
  • Grapefruit: 483
  • Onion: 450
Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers for dispersion, emulsification and cell extraction.

High-power ultrasonic homogenizers from lab to pilot and industrial scale.