ULTRASONIC EXTRACTION
A number of bioactive compounds are responsible for imparting different medicinal properties
in the plants. These compounds are synthesized as secondary metabolites, which aid in the
overall survival in plants by allowing their interaction with the surrounding environment. They
have been broadly classified as: (A) terpenes and terpenoids, (B) alkaloids, and (C) phenolic
compounds (Azmir et al., 2013). Of these, the phenolic compounds constitute one of the most
widely distributed groups of secondary metabolites in the plant kingdom and are well known
for their antioxidant behavior. Flavonoids represent another class of low-molecular-weight
phenolic compounds, which are also very effective antioxidants and less toxic than their
synthetic counterparts such as BHT and BHA (Bimakr et al., 2011). Cannabis sativa L.
(hereinafter: Cannabis) has been around since ages and cultivated as an annual crop plant for
its commercial JFDS-2017-1777 Submitted 10/29/2017, Accepted 1/14/2018. Authors Agarwal
and Csoka are with Inst. of Wood Based Products and Technologies, Univ. of ´ Sopron, Bajcsy-
Zsilinszky u. 4, Sopron 9400, Hungary. Author Math ´ e is with ´ Inst. of Applied Arts, Univ. of
Sopron, Bajcsy-Zsilinszky u. 4, Sopron 9400, Hungary. Author Hofmann is with Inst. of
Chemistry, Univ. of Sopron, BajcsyZsilinszky u. 4, Sopron 9400, Hungary. Direct inquiries to
author Csoka (E-mail: ´ levente.csoka@skk.nyme.hu). value. It belongs to the family of
Cannabinaceae and has long been used in traditional Asian medicine, particularly in India
(Happyana et al., 2013). Reportedly, the 1st successful attempt to extract active compounds
from the flowers and leaves of Cannabis was made by Schlesinger in 1840 (Mechoulam &
Hanuˇs, 2000). The phenolic compounds are comprised of phenolic acids such benzoic and
hydroxycinnamic acids, flavonoids such as flavones and flavonols, lignans, and stilbenes
(Andre, Larondelle, & Evers, 2010). About 34 phenols and 23 flavonoids have been identified in
Cannabis (ElSohly, 2007). Besides the common phenolic compounds, Cannabis has been widely
explored for phytocannabinoids (or simply cannabinoids) which are unique to the plant.
Cannabinoids represent a group of C21 terpenophenolic compounds and are usually
concentrated in the female inflorescence, the plant being dioecious. Among the 483
compounds in Cannabis, about 66 have been identified as cannabinoids (ElSohly, 2007). The
most important cannabinoid with psychoactive properties is 9-tetrahydrocannabinol (THC).
The predominant cannabinoids, which are biosynthesized in acidic form, include THC,
cannabidiol (CBD) and cannabinol (CBN), followed by cannabigerol (CBG), cannabichromene
(CBC), and cannabinodiol (CBND). Cannabinoids have shown immense therapeutic potential;
the most common ones being palliative effects such as treatment of nausea and emesis in
patients undergoing chemotherapy, stimulation of appetite in HIV-positive patients and
spasticity associated to multiple sclerosis in adults (Andre, Hausman, & Guerriero, 2016). They
have also shown promise as antitumor or anticancer agents and in treating ailments like
glaucoma, epilepsy, and schizophrenia (Alexander, 2016; Guzman, 2003). The isolation of these
bioactive compounds and their separation from the plant matrix is made complicated due to
their sensitivity to various process parameters such as temperature as well as the coextraction
of other undesirable components (Bimakr et al., 2011). Conventional methods for extraction
such as Soxhlet extraction, maceration and hydro-distillation have the major drawbacks of
longer time needed for extraction and large amounts of solvent needed. In order to overcome
these limitations, a number of nonconventional techniques have been lately focused on which
include extractions assisted by ultrasound, microwave, enzymes, pulsed electric field,
supercritical fluid extraction and pressurized liquid extraction (Azmir et al., 2013). Of these,
ultrasonication has been widely employed for the extraction of bioactive compounds (Khan,
Abert-Vian, Fabiano-Tixier, Dangles, & Chemat, 2010; Muniz-Marquez et al., 2013; Spigno,
Tramelli, & De Faveri, 2007). This technique relies on the phenomenon of bubble formation
and their violent collapse called cavitation, which results in local hotspots with temperature of
the order of 104 K and pressure as high as 103 bar (Iskalieva et al., 2012). It allows the target
compounds to dissolve in the solvent by disrupting the cell wall, thus enhancing yield in much
lesser time (Shirsath, Sonawane, & Gogate, 2012). The present study aimed to extract
bioactive compounds using the principle of ultrasound from the inflorescences of fibertype
Cannabis having THC/CBD 1.0. The evaluation was done by analyzing the influence of factors
such as time, input power and solvent composition on extract properties by using response
surface methodology (RSM) by measuring total phenol and total flavonoid (TF) contents, FRAP
(ferric reducing ability of plasma) antioxidant capacity and overall yield of the extracts. The
identification and comparative evaluation of the amounts of major cannabinoid compounds
(CBG and tetra-hydrocannabinol [THC]) was carried out using HPLC-DAD-MS/MS technique.
Finally, the extraction conditions were optimized and the predicted values of the responses
were compared to the experimentally obtained values to validate the model. To the best of
our knowledge, extraction of bioactive compounds from Cannabis inflorescences using the
principle of ultrasound along with the optimization of critical process parameters has not been
attempted before. This work is expected to encourage the exploration of the potentially useful
compounds present in Cannabis by their facile extraction achieved by ultrasonication.
Materials and Methods Materials Plant material. The inflorescences of fiber-type hemp
(Cannabis sativa L., Hungary), comprising mainly of the top portion including the flowers,
leaves, and seed husks, were harvested in the previous summer. They were dried well and
stored in a dark room at ambient temperature until further analysis. Chemicals. Methanol of
analytical grade was purchased from Scharlab Magyarorszag Kft. Folin and Ciocalteu’s phenol
reagent (2N); gallic acid and sodium acetate buffer solution (3M) were purchased from Sigma
Aldrich. Ferric chloride (hexahydrate), sodium carbonate and L-ascorbic acid were obtained
from Reanal, Budapest, Hungary. 2-aminoethyl diphenyl borinate was purchased from Alfa
Aesar while 2,4,6-tri(2-pyridyl)-1,3,5-triazine from TCI. Quercetin dihydrate was procured by
Fluka AG, Chem. Fabrik. HCl used was obtained from Merck.
Ultrasonic extraction. Plant samples weighed to 2.5 g were mixed with 50 mL of
methanol/water solvent in ratios of 20%, 50%, and 80% (v/v) in slender glass beakers, covered
with a parafilm in order to avoid solvent evaporation. The probe was inserted in the beaker
such that the distance from the tip to the base of the beaker was approximately half the
calculated ultrasonic wavelength to achieve maximum cavitation and efficiency of sonication.
Extractions were carried out at low, medium and full power 2 Journal of Food Science Vol. 0,
Nr. 0, 2018 Food Engineering, Materials Science, & Nanotechnology Extraction of cannabinoids
. . . inputs of 90, 120, and 150 W, respectively. The time for sonication was varied at 5, 10, and
15 min. The sonicated samples were allowed to cool down naturally and thereafter, filtered
through filter paper in glass bottles. The extracts were stored away from light at ambient
temperature (around 5 °C) until further analysis. The energy efficiency of the ultrasonic horn
was calculated by calorimetrically determining the actual energy dissipated according to an
already documented method (Gogate et al., 2001). The input power levels adjusted to
amplitudes of 60, 80, and 100% consumed 90, 120, and 150 W, respectively. The actual power
dissipated from the probe tip into the bulk of the medium was calculated by measuring the
rise in temperature of a given quantity of water in a given time. The actual power dissipation
values corresponding to power inputs of 90, 120, and 150 W were calculated as 31.4, 41.8, and
52.3 W, respectively. The average energy efficiency of the horn was found to be around 34.9%
from the calorimetric studies. Control extraction. A control experiment was run without
ultrasound in order to make a comparative study. The plant sample (2.5 g) was mixed with 50%
methanol (50 mL) in a beaker and stirred continuously on a magnetic stirrer at 300 rpm at 60
°C for 30 min. After cooling it, the filtered extract was also stored away from light in ambient
conditions until further analysis. Determination of total phenolic content (TPC). The TPC of
extracts was determined by the Folin & Ciocalteu (FC) assay. The addition of FC reagent to
phenolic compounds leads to the formation of blue-colored
phosphomolybdic/phosphotungstic complex due to electron transfer in alkaline medium
(Ainsworth & Gillespie, 2007). In a typical procedure, 0.5 mL each of extract followed by FC
reagent were mixed vigorously in a 10 mL volumetric flask. After 2 min, 2.5 mL of 7.5% Na2CO3
solution was added and the remaining volume was made up with distilled water. A blank
solution was prepared with the same procedure without the extract. All the samples were kept
in dark and ambient temperature for 2 hr. Thereafter, the absorbances were measured using
the UV/vis spectrophotometer at 765 nm against the blank sample as the reference. Standard
solutions of gallic acid in the concentration range of 0.1 to 0.5 mg/mL were used for plotting
the calibration curve. All the measurements were made in triplicate and mean values were
expressed in milligrams gallic acid equivalent per gram dry weight of plant (mg GAE/g DW).
Determination of TF. The flavonoids were determined by slightly modifying a method
previously reported (Teh & Birch, 2014). In a 10 mL volumetric flask, 1 mL of extract was mixed
with 0.1 mL of 1% (v/v) methanolic solution of 2-aminoethyl diphenyl borinate and the
remaining volume was made up with distilled water. The absorbances were measured
spectrophotometrically at 404 nm after “zeroing” the blank solution. Quercetin solutions in the
range of 0.05 to 0.3 mg/ mL were used as standards for the calibration curve. The mean results
were reported in milligrams quercetin equivalent per gram dry weight of plant (mg QE/g DW).
Determination of FRAP antioxidant capacity. The FRAP assay measures the antioxidant power
by reduction of the ferric ions through electron transfer reactions. The FRAP reagents were
freshly prepared each time before analysis. As given in a similar procedure by Benzie and
Strain (Benzie & Strain, 1996), 100 mL of sodium acetate buffer (0.3 M, 3.6 pH) was mixed with
10 mL of 2,4,6-tri(2-pyridyl)-1,3,5-triazine (TPTZ) solution (10 mM) by dissolving it in 40 mM
HCl in a hot water bath. This was followed by the addition of 10 mL of ferric chloride solution
(20 mM) and 12 mL of distilled water to give a straw-colored reagent. This ferric-TPTZ complex
changes to its ferrous form Table 1–Design space factors and levels. Factor levels Factor Unit
−10 1 Time, A min 5 10 15 Power, B W 90 120 150 Solvent, C % 20 50 80 in the presence of
antioxidants that act as electron donors, which can be confirmed by the appearance of a dark
violet color. 0.1 mL of extract was mixed with 5 mL of FRAP reagent and incubated at 37 °C in a
water bath in a dark room for 30 min. The blank was also prepared in a similar fashion without
the extract. The absorbances were determined at 593 nm by the spectrophotometer against
the blank as the reference. Ascorbic acid standards in the range of 0.1 to 1.6 mM were used
for the calibration curve. The mean values were expressed in millimoles ascorbic acid
equivalent per gram dry weight of plant (mM AAE/g DW). Yield determination. The yield of the
extracts was determined by drying a known weight of extract in a glass petridish, in an oven at
50 °C for 4 h. After ensuring complete evaporation of the solvent, the extracts were reweighed
and the yield was calculated as a percentage of the dry weight of plant
Results and Discussion Extraction process and factor selection For proper resource utilization
and process optimization, the selection of the right technique and the governing factors plays
a crucial role. The extraction of bioactive compounds was assisted by ultrasonic waves (20
kHz), which create compression and expansion in the medium causing the formation, growth
and collapse of bubbles known as cavitation. It causes the swelling and rupture of cell walls,
followed by leaching of cellular components by mass transfer into the solvent due to the
diffusion across the plant cell wall and subsequent washing-out of the contents (Azmir et al.,
2013). The low frequency of sonication used here leads to stronger physical effects which aid
the extraction process (Iskalieva et al., 2012). Compared to the conventional extraction
techniques, ultrasonication facilitates faster mass and energy transfer, uniform mixing and
reduced thermal gradients, thus leading to shorter extraction times at lower temperatures.
Temperature, time, solvent, power, and frequency are the main parameters affecting the
efficiency of ultrasonication (Azmir et al., 2013). The time and temperature can have either
positive or negative impact on extraction and hence, should be considered cautiously. Longer
sonication time may result in the degradation of some thermolabile compounds due to higher
temperature. Additionally, it also increases the energy and operational costs (Tomsik et al.,
2016). In this study, time was chosen as one of the influencing factors for the design, as it is
easier to monitor and control time over temperature. Further, they are also directly linked as
the temperature increases with time due to the large amount of heat generated continuously
in the process. Another factor considered for process study was the power of sonication. It
affects the intensity of ultrasonic waves passing through the solvent medium and thereby, can
have a profound impact on the extraction process. The third factor, solvent plays a key role
during sonication by dissolving the compounds of interest and chosen based on the selectivity
of the targeted compounds. Methanol has been widely employed as a preferred solvent for
extraction of plant components such as the phenolic antioxidants (Azmir et al., 2013). The
selection of solvent also depends on its safety or toxicity, cost, and availability.
Many cannabis extraction methods exist for creating marijuana
concentrates. From the ancient craft of creating hashish to modern
approaches like supercritical CO2 and hydrocarbon solvent extraction, each
technique has its own benefits and pitfalls. Despite the myriad of methods
and setups, simple alcohol-based extraction continues to prove popular for
producers of all sizes. Extractors opt for alcohols like ethanol because they
are cheap, safe, easy to handle and very effective at extracting desirable
compounds from plant material. That’s not to say that alcohol extraction is
without it’s challenges. It’s polarity, for example, means that it mixes with
water and dissolves water-soluble molecules like chlorophyll which must
then be removed to avoid creating a bitter extract. As with any extraction
process, there is always a demand to reduce costs and runtime and improve
the extraction of desirable compounds. The team at Sopron University set
out to take a simple alcohol extraction setup and enhance its performance
with the addition of an ultrasonicator.
Corresponding author Professor Levente Csoka of the Institute of Wood
Based Products and Technologies explained “Ultrasonication is a relatively
inexpensive and simple technique to use considering the small amounts of
solvents needed for extraction. We believe it can be used to reduce runtime
and the energy required compared to other conventional techniques such as
Soxhlet extraction, maceration and hydro-distillation, which are both
laborious and time-consuming.” In simple terms, ultrasonication aids
extraction via the rapid formation of microbubbles which then violently
collapse. Known as cavitation, this causes tiny localised hotspots with
temperatures of the order of 104 K and pressures as high as 103 bar. These
extreme conditions disrupt the cell wall and allow target compounds to
dissolve into the solvent more readily.
Prof. Csoka went on to say “Ultrasonic-based extraction techniques have
already been applied to a number of plants, such as Curcuma amada,
Ocimum tenuiflorum and vanilla pods, as well as bioproducts such as
strawberries, citrus peels and carrot residues. As far as cannabis is
concerned, a few reports are available on its ultrasonic extraction, but
extraction from inflorescence has not been considered .”
The idea behind this research was to enable the transfer of a well-
established extraction technique for other botanical products into the
cannabis industry.
Developing an ultrasonic extraction method
The end goal of the research was to identify the optimal setup for
ultrasound-assisted extraction. This hinged on testing the impact of adjusting
three independent factors, namely time, input power and solvent
concentration. Methanol was selected as the solvent due to its compatibility
with the desired extract components. Professor Csoka explained “The
polarity of the solvent significantly affects the extraction process. Methanol is
a proven solvent for the extraction of polyphenols, flavones, terpenoids, etc.
But, it would be interesting to study the influence of changing the extraction
solvent to see what affect it has on the properties of the extract.” In this case
the team opted to test their technique on industrial hemp which has a very
low concentration of the main psychoactive component of cannabis, ∆9-
THC. But, they were keen to highlight that this technique can just as easily
be applied to any cannabis chemotype.
Focusing on the highlights of the study, ultrasonication was found to have a
significant beneficial impact on extraction across the board. Demonstrating
the potential of this approach, ultrasonic extraction done for just 15 minutes
doubled extraction efficiency compared to a 30 minute control extraction. In
particular, the extraction of cannabinoids was enhanced considerably - as
confirmed by high-performance liquid chromatography coupled to diode
array and mass spectrometry detectors (HPLC-DAD MS/MS) analysis.
In summary of their findings and the benefits of ultrasonication, the team
said “What we have found can be attributed to more effective mixing, faster
energy transfer and reduced thermal gradients during the process. As added
benefits, the equipment size is small compared to other extraction
techniques, responds rapidly to changes to process parameters and is quick
to start up - all leading to increased production and the elimination of
process steps.”
At this stage though, not everything is clear. The potential negative impacts
of ultrasonic must also be considered. Professor Csoka explained “The
thermal stability of the compounds of interest must be considered. As for
cannabinoids, the acidic ones are more susceptible to degradation than the
neutral ones. At high ultrasonic powers and long sonication times,
degradation of these thermolabile compounds may occur considering the
extremely high temperatures attained inside the cavitation bubble. On the
other hand, there may be compounds, which require the kind of extreme
conditions of ultrasound to be separated from the plant matrix and dissolved
into the extraction solvent.”
Meeting the global demand for cannabis extracts
The team at Sopron are now planning to build on this initial success. This
was in fact their first foray into botanical extraction and cannabis research –
usually they focus on cellulose composites and their functional modifications.
Prof. Csoka said “For us, the next step may be to look into the applications
of the extracted cannabinoids by their separation and immobilization into a
suitable matrix or, by using them as a green chemical (reducing agents) to
create nanoparticles.”
With the rapid increase in demand for cannabis extracts, this paper
highlights a real opportunity for the optimization of alcohol-based extraction
in a growing global market. Simplicity and ease of use may prove to be big
draws for this technology. The major operating parameters
time/temperature, power/amplitude, frequency, solvent composition and
solute to solvent ratio can all be easily tuned as required, thus making this a
very accessible solution. However, whether this approach can be scaled up
to mass production quantities remains to be seen.
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Comments
Jack Rudd
Managing Editor analytical cannabis
Ultrasonic extraction is the next leap forward in cannabinoid extraction
techniques. Due to the continually moving goal post of cannabis law, the
medicinal cannabis industry is experiencing an explosion of technological
advancements. This is especially true when it comes to exploring novel new
methods for extracting viable therapeutic compounds like cannabinoids.
Image Courtesy of Industrial Sonomechanics, LLC. BSP-1200 BENCH-SCALE
PROCESSOR
Extraction has gone from rudimentary ethanol solvent based procedures, which
technically could be done in a garage, to increasingly complex and expensive
devices. These new extractors require significant technical know-how and
typically require a substantial financial investment, sometimes into the tens of
thousands of dollars.
Ultrasonic extractors also referred to as ultrasonic emulsifiers, are part of the
new wave of extraction science. This innovative method is substantially less
costly than other advanced technologies on the market. This has opened up the
playing field for small to medium-sized operations to significantly improve their
extraction processes.
Benefits Of Ultrasonic Extraction
Sonication, a term which refers to the use of ultrasonic waves, has become
increasingly popular since its release. It comes as no surprise to industry
veterans, who know that most commonly practiced extraction techniques come
with unavoidable problems. The benefits of sonication easily beat out the
competition, and often with much less investment.
Ultrasonic extraction has a number of benefits, for a producer's bottom line as
well as the quality of the final product. For one, sonication is a much more
environmentally friendly extraction method that does not rely on harsh solvents
to extract the cannabinoid. Another main reason for the rise of ultrasonic
extraction is that the entire process takes a matter of minutes to complete.
Other methods take hours, sometimes days to deliver a final product. Plus, as
mentioned earlier, it is much more economical than other mechanisms.
The mechanism is widely adaptable to many different applications, from
commercial to industrial, to medicinal products. The ultrasonic extractor can be
used with many different solvents. Depending on what the final product
requires, an ultrasonic extraction method can work with a variety of substances
such as ethanol, CO2, H2O, olive oil, coconut oil, and many others.
Importantly, for producers who care about preserving the integrity and
concentration of cannabinoids and terpenes, ultrasonic extractors do not rely on
heat. Extraction methods which rely on high heat quickly destroy the sensitive
cannabinoid content, which subsequently destroys much of the whole-plant
medicinal benefit. Many suppliers advertise the fact that these extraction
methods are extremely low thermal and do not require temperatures to go
above 60 degrees Celsius.
How Does Ultrasonic Cannabis Extraction Work?
Ultrasonic extraction addresses the extremely problematic fact that
cannabinoids, like THC and CBD, are naturally hydroponic. Without harsh
solvents, it is often difficult to expel the precious cannabinoids from within the
cell interior. To increase the bioavailability of the final product, producers need
to find extraction methods that break down the tough cell wall.
The technology behind ultrasonic extraction is anything but easy to understand.
In essence, sonication relies on ultrasonic waves. A probe is inserted into a
solvent mixture, and the probe then emits a series of high and low-pressure
sound waves. This process essentially creates microscopic currents, eddies,
and pressurized streams of liquid, forming a particularly harsh environment.
These ultrasonic sound waves, which emit at a speed of up to 20,000 per
second, create an environment that breaks through cellular walls. The forces
which typically work to hold the cell together are no longer viable within the
alternating pressurized atmosphere created by the probe.
Millions upon millions of tiny bubbles are created, which subsequently pop,
leading to the complete breakdown of the protective cell wall. As the cell walls
break down, the inner materials are released directly into the solvent, thus
creating a potent emulsion.
Building Off Ultrasonic Methods
The sonication emulsion process can be combined with many other extraction
methods to create even higher concentrations. Unlike other less-advanced
processes, the ultrasonic method is remarkably reproducible. All the parameters
can be meticulously set, and then easily replicated.
Building off the already high-quality products produced through ultrasonic
extraction, producers can combine with other methods to improve the final
cannabinoid potency. For example, liposomal technology is often combined with
sonication in order to increase the bioavailability of the final product.
Liposomal technology takes substances, like CBD which are naturally
hydroponic, and transforms them into water-soluble substances. Liposomes are
essentially tiny messengers working within the human body, and by
encapsulating cannabinoids within this process, producers can develop a
powerful therapeutic agent.
JESSICA MCKEILJessica McKeil is a freelancer
Ultrasonic Extraction of
Cannabis Sativa L.
By Jean-Raphaël Sauvonnet
CANNABIS EXTRACTION
Extracts from Cannabis have been used since ages for its pain-relieving and
sleep-inducing properties. Cannabidiol (CBD), a phytocannabinoid is the
most researched cannabis molecule owing to its therapeutic effects on the
Endocannabinoid System. CBD profoundly affects and enhances mental
alertness, and is therapeutically indicated in the management of convulsion,
inflammation, anxiety, and nausea, and to inhibit cancer cell growth.
Research studies claim that CBD can be as beneficial as atypical
antipsychotics in managing schizophrenia and ADHD.
The different methods of Cannabis extraction
(REFLUX/ULTRASONIC)
For the process of extraction of the cannabis material, the cannabis plant is
determined into respective cannabinoids categories Acid (CDBA –
Cannabidiolic acid), Activated (CBD) and Analog form (CBDV-
Cannabidivarin); thereafter the cannabis material is ground and the ground
material is heated at predetermined temperatures prior to refluxing or using
the ultrasonic to induce a decarboxylation of CBDA into CBD. The extracted
material (CBD) is then infused with an alternative to alcohol (solvent) in a
predetermined ratio and is optimized in appropriate potency to be used for
the selected purpose.
The main steps in ultrasonic extraction
Drying – The cannabis plant is thoroughly air-dried till the leaves next to the
flowering tops are brittle. Duration involved in drying comprises of 24 to 72
hours and is dependent on humidity and ambient temperature. For optimum
extraction the plant needs to be dry (allowed residual water content is 8-
10%).
Sorting – Before crushing of the plant, the flowers, leaves and the stalks are
separated. Seeds are removed. And then the rest of the material is crushed.
Grinding – With the help of a grinder, the coarsely crushed cannabis material
is grounded. It is advised to grind the chopped stems separately and then
mix it with rest of the ground material to obtain uniform consistency of the
powder.
Pre-processing quantitative assessment – This next step consists of a
process which involves of classifying the total plant material into three types
and according to CBDA, CBD and CBDV percent of phytocannabinoids per
gram of dry weight plant material the amount of solvent (percent of grams) is
determined.
The CBD % gram of plant material can be determined from one of the
following ways through analysis with a cannabinoid detection kit, Analysis
from a gas or liquid chromatograph, strain based estimate or from personal
experience. A processor executing computer readable code is used to
choose the plant material (CBD) to solvent amounts incorporating a
predetermined ratio;
Extraction processing – an ultrasonic probe is coupled to a processor
capable of converting electric energy into high frequency sounds. Ultrasonic
extractors use sound waves to transfer cannabinoids from the cannabis
plant material to a solvent matrix. The processor combined with the
ultrasonic extractor controls multiple complex factors such as amplitude,
frequency (Hz) and temperature. The main function of the equipment is to
ensure the extractor effectively infuses the cannabinoids while maintaining
their physical state integrity.
When using an ultrasonic extractor, heating (the plant material is heated at
a predetermined temperature; temperature above 200 (f) converts the acids
from the plant material (CBDA) into the neutrals (CBD) – and or into the
analogs – decarboxylation) can be achieved or not. Ultrasonic extraction
takes less than 15 minutes and can be achieved in cryogenic temperatures,
to preserve the cannabinoids acidic forms.
THE ADVANTAGES OF USING ULTRASONIC EXTRACTION
It is an environmentally friendly process which does not involve the use of
harsh solvents to extract the CBD. The duration involved in extraction is
extremely shortened as compared to reflux or heating. Ultrasonic extraction
mechanism is suitable for varied applications ranging from commercial to
industrial to medicinal products. The ultrasonic extractor can process various
solvents (ethanol, H2O, D-limonene, olive oil and many others) It is superior
to Co2 Supercritical extraction, as ultrasonic extraction preserves the
integrity and concentration of the cannabinoids and terpenes. Ultrasonic
extractors do not require heat or pressure at all. Other conventional
methods of extraction, require substantial investments (large-scale C02
Supercritical equipments are priced above 100.000$), synthetic materials,
complex chemicals, or toxic gases such as petroleum ether, benzene,
butane and other gases to extract. The cannabis extracts derived via these
conventional methods consist of toxic materials resulting in potentially
harmful by-products. Finally it does not incorporate chromatographic
fractioning. This process is able to create higher potencies while not
compromising the final product quality.
REFERENCES
https://patents.google.com/patent/US8445034B1/en – Systems and methods
for producing organic cannabis tincture
One might ask about the need for a more sophisticated unit. The answer is
simple. It provides cannabis processors with the ability to develop and
customize optimum processing steps to achieve consistent, high-quality product
from a variety of sources.
How the Process Works
When activated, the equipment’s generator powers the transducers to vibrate at
their designed ultrasonic frequency. This vibration causes the tank bottom to
vibrate as a membrane that produces countless microscopic vacuum bubbles.
In applications such as cleaning glassware, these bubbles implode with
tremendous force in a process called cavitation. This cavitation quickly and
safely blasts loose contaminants and carries away even the most tenacious
residue. Products are cleaned with a solution formulation designed for the
application.
In a processing application, products are contained in Erlenmeyer flasks, test
tubes, or beakers. These containers are lowered, but not fully immersed, into a
water or surfactant solution. Ultrasonic energy passes through the glass walls of
the containers to act on the contents.
This approach achieves the homogenizing, emulsifying, degassing, and other
cannabis processing steps in a fast, efficient, and environmentally friendly way.
Comparing Ultrasonic Cannabis Production and Quality Control to Alternative
Methods
In 2015, the National Hemp Association published an article in Hemp News
titled “Five Major Types of Cannabis Extraction” (2). In the article, Rien Havens,
PhD, CTO, Really Helping, PBC, stated that in the winter of 2014 he began
research to develop the optimal methods of hemp extraction. “It was quite a
ride. I had in mind three main goals,” said Havens. “No use of fossil fuels, low
energy footprint, and cost effectiveness.”
Here, we paraphrase Havens’ findings as published in the article (2). Readers
may wish to access the full article for additional details.
Ethanol produced a relatively good quality extract, but the solvent and energy
costs were high. It did not produce the desired results of volume and speed.
Residual solvent in the final product was also a drawback.
A closed-loop hydrocarbon extractor is inexpensive to set up, but uses fossil
fuels, almost always contains cancer-causing components like benzene, and
often there are metal filings and welding debris in the solvent tanks.
A supercritical carbon dioxide extractor was able to produce a high quality
extract with very high terpene retention, a great color, taste, speed, and
selectivity. The downside of this approach includes high overhead and unruly
energy consumption.
Critical water extraction is “green” with no added solvents but clean water.
There is no solvent loss, or cost, and the volume and cost of the extractor
makes it a good candidate for industrial hemp extraction.
A truly solventless method is sonic and ultrasonic waves in the plant matter that
push the product out through vibration. This method can also be scaled up, like
water extraction on a budget, and produces a very nice, high-quality extract.
A Closer Look at Ultrasonic Equipment for Cannabis Production
Ultrasonic cleaner tanks are available in multiple sizes in terms of length, width,
and depth. When processing in flasks and beakers, a shallow-depth tank is a
good choice with a length and width that allows the processing of several
containers at once.
The following sections provide a more detailed illustration of how the process
works. This example describes the use of a 37-kHz ultrasonic cleaner based on
its tank configuration and operating features.
Remember that the transformation or extraction process avoids chemical
degradation that can be caused by excessive heat or mechanically induced
damage.
Extraction and Processing Steps
Product is placed in flasks along with a recommended solvent. Flasks are
partially immersed in a sonicator bath containing a surfactant.
The tank configuration of the ultrasonic unit used in this process is especially
designed to quickly and safely accomplish extraction and further processing.
The inside dimensions of the shallow basket, 17.9 x 9.8 x 2.2 in. (LxWxH),
facilitate positioning of multiple smaller containers or larger beakers. Flask
clamps are used to affix flasks to the mesh-bottom basket; test tube holders are
also available.
The equipment described was also selected because of its high ultrasonic
power per unit volume. This feature permits the preparation process to be
completed before heat buildup, a natural result of ultrasonic energy, which can
degrade product. If heat is a concern, a useful accessory is a cooling coil to
prevent temperature increase. The cooling coil must be attached to a source of
recirculating cold liquid such as a laboratory chiller.
