Ultrasonic Extraction and Preservation
Ultrasonic extraction and preservation utilizes using power ultrasound for the disintegration of cell structures (lysis). Breaking cells with ultrasonics rersults in highly efficient extraction of intra-cellular compounds as well as microbial inactivation. Due to numerous advantages, ultrasonication is widely used for extraction and preservation in the food industry. Learn more about the benefits of ultrasonic extraction and food processing!
Power Ultrasound for the Extraction and Preservation of Food and Botanicals
Ultrasonic Extraction: Ultrasonic extraction is a process that uses high-frequency sound waves to extract compounds from a variety of materials such as plants, fruits, and vegetables. The process involves the use of ultrasonic waves to create high-pressure bubbles in a liquid or semi-solid material, which collapse rapidly, generating intense heat and pressure that disrupts the cell walls of the material and releases the desired compounds.
The Working Principle of Ultrasonic Extraction and Preservation
The basic principle behind ultrasonic extraction is based on the phenomenon known as acoustic cavitation. When a liquid is exposed to ultrasonic waves of high intensity and low frequency (approx. 20 kHz), it generates pressure waves that create tiny vacuum bubbles in the liquid. These bubbles grow in size as the intensity of the ultrasound increases, and when they reach a certain size, they collapse suddenly and violently, generating a shock wave and releasing energy in the form of heat and pressure.
This process causes mechanical disruption of the cell walls, releasing the desired compounds from the material into the liquid solvent. The released compounds can then be separated from the solvent using standard separation techniques such as filtration or centrifugation.
Ultrasonic Preservation: Ultrasonic preservation is based on the same cavitational effects as ultrasonic extraction. For preservation, power ultrasound is applied to extend the shelf life of perishable foods by using high-frequency sound waves to inhibit the growth of microorganisms that cause spoilage. The process involves exposing the food to ultrasonic waves that disrupt the cell walls of bacteria, yeasts, and molds, leading to their destruction or inhibition.
This process causes mechanical disruption of the cell walls of microorganisms, leading to their destruction or inhibition. Ultrasonic waves can also increase the permeability of cell membranes, allowing preservatives and other antimicrobial agents to penetrate and kill the microorganisms more effectively.
Ultrasonic preservation is preferred over traditional preservation methods because it offers several advantages such as shorter processing time, higher efficiency, and the ability to preserve the natural properties and flavors of the food. It is used in a wide range of food products such as sauces, juices, dairy products, eggs, and meat to extend their shelf life and ensure their safety.
The ultrasonic extraction and preservation technique is preferred over traditional extraction and preservation methods because it offers several advantages such as faster extraction rates, excellent product quality, higher yield, purely mechanical non-thermal treatment and the ability to extract a broader range of compounds. It is used in a wide range of industries such as food and beverage, pharmaceuticals, and cosmetics.
Ultrasonic Protein and Enzyme Extraction
In particular the extraction of enzymes and proteins stored in cells and subcellular particles is a unique and effective application of high-intensity ultrasound, as the extraction of organic compounds contained within the body of plants and seeds by a solvent can be significantly improved. Therefore ultrasound has a potential benefit in the extraction and isolation of novel potentially bioactive components, e.g. from non-utilized by-product streams formed in current processes. Ultrasound can also help to intensify the effects of enzyme treatment, and by this reduce the amount of enzyme needed or increase the yield of extractable relevant compounds.
Ultrasonic Extraction of Lipids and Proteins
Ultrasonication is often used to improve the extraction of lipids and proteins from plant seeds, such as soybeans (e.g. flour or defatted soybeans) or other oil seeds. In this case, the destruction of the cell walls facilitates the pressing (cold or hot) and thereby reduces the residual oil or fat in the pressing cake.
The influence of continuous ultrasonic extraction to the yield of dispersed protein was demonstrated by Moulton et al. The sonication increased the recovery of dispersed protein progressively as the flake/solvent ratio changed from 1:10 to 1:30. It showed that ultrasound is capable to peptize soy protein at almost any commercial throughput and that the sonication energy required was the lowest, when thicker slurries were used.
Ultrasonic Isolation of Phenolic Compounds and Anthocyanins
Enzymes, such as pectinases, cellulases and hemicellulases are widely used in juice processing in order to degrade cell walls and improve the the juice extractability. The disruption of the cell wall matrix also releases components, such as phenolic compounds into the juice. Ultrasound improves the extraction process and therefore can lead to an increase in the phenolic compound, alkaloids and juice yield, commonly left in the press cake.
The beneficial effects of ultrasonic treatment on the liberation of phenolic compounds and anthocyanins from grape and berry matrix, in particular from bilberries (Vaccinium myrtillus) and black currants (>Ribes nigrum) into juice, was investigated by VTT Biotechnology, Finland using an ultrasonic processor UIP2000hd after thawing, mashing and enzyme incubation. The disruption of the cell walls by enzymatic treatment (Pectinex BE-3L for bilberries and Biopectinase CCM for black currants) was improved when combined with ultrasound. “US treatment increase the concentration of phenolic compounds of bilberry juice by more than 15%. […] The influence of US (ultrasound) was more significant with black currants, which are more challenging berries in juice processing than bilberries due to their high content of pectin and different cell wall architecture. […] the concentration of phenolic compounds in the juice increased by 15-25% by using US (ultrasound) treatment after enzyme incubation.” (cf. Mokkila et al., 2004)
Microbial and Enzyme Inactivation
Microbial and enzyme inactivation (preservation), e.g. in fruit juices and sauces is another application of ultrasound in the food processing. Today, preservation by elevation of temperature for short periods of time (Pasteurization) is still the most common processing method for microbial or enzyme inactivation that leads to longer shelf-life (preservation). Because of the exposure to high temperature, the conventional thermal pasteurization comes often disadvantages for food products.
The production of new substances from heat-catalyzed reactions and the modification of macromolecules as well as the deformation of plant and animal structures may reduce in a loss of quality. Therefore, thermal treatment can cause undesirable alterations of sensory attributes, i.e. texture, flavor, color, smell, and nutritional qualities, i.e. vitamins and proteins. Ultrasound is an efficient non-thermal (minimal) processing alternative.
In contrast to conventional heat treatments, ultrasonic preservation uses the energy and shear forces of acoustic cavitation in order to inactivate enzymes. At sufficiently low levels of sonication structural and metabolic changes can occur in cells without their destruction. The activity of Peroxidase, which is found in most raw and unblanched fruits and vegetables and can be particularly associated with the development of off-flavors and browning pigments can be reduced substantially by the use of ultrasound. Thermoresistant enzymes, such as lipase and protease that withstand ultra-high-temperature treatment and which can reduce the quality and shelf-life of heat-treated milk and other diary products can be inactivated more effectively by the simultaneous application of ultrasound, heat and pressure (MTS).
Ultrasound has demonstrated its potential in the destruction of food-borne pathogens, like E.coli, Salmonellae, Ascaris, Giardia, Cryptosporidium cysts, and Poliovirus.
Applicable to: preservation of jam, marmalade or toppings, fruit juices and sauces, meat products, dairy and ice cream.
Synergies of Ultrasound with Temperature and Pressure
Ultrasonication is often more effective when combined with other anti-microbial methods, such as:
- thermo-sonication, i.e. heat and ultrasound
- mano-sonication, i.e. pressure and ultrasound
- mano-thermo-sonication, i.e. pressure, heat and ultrasound
The combined application of ultrasound with heat and/or pressure is recommended for Bacillus subtilis, Bacillus coagulans, Bacillus cereus, Bacillus sterothermophilus, Saccharomyces cerevisiae, and Aeromonas hydrophila.
Ultrasonics vs Other Food Preservation Techniques
Unlike other thermal and non-thermal processes, such as high-pressure homogenization, heat pasteurization, high hydrostatic pressure (HP), compressed carbon dioxide (cCO2) and supercritical carbon dioxide (ScCO2), high electric field pulses (HELP) or microwave, ultrasound can be easily tested in lab or bench-top scale – generating reproducible results for scale-up. The intensity and the cavitation characteristics can be easily adapted to the specific extraction process to target specific objectives. Amplitude and pressure can be varied in a wide range, e.g. to identify the most energy efficient extraction setup.
Other advantages linked with the use of ultrasonic probe-type extraction are easy handling of extract, rapid execution, no residues, high yield, eco-friendly, enhanced quality and prevention of extract degradation.
(cf. Chemat et al., 2011)
- More complete extraction
- Non-thermal preservation
- Higher yields
- High nutrients, premium food quality
- Rapid process
- Cold / non-thermal process
- Easy and safe to operate
- Low maintenance
High Performance Ultrasonicators for Extraction and Preseravation
Hielscher Ultrasonics designs, manufactures and distributes high-performance ultrasonicators for efficient extraction and preservation. Using Hielscher ultrasonic equipment for extraction and food preservation is a powerful processing technology that can not only be applied safely and environmentally friendly but also efficiently and economically. The homogenizing and preserving effect can be easily used for any liquid or paste-like food product including fruit juices and purees (e.g. orange, apple, grapefruit, mango, grape, plum) as well as for vegetable sauces and soups (e.g., tomato sauce or asparagus soup), dairy, eggs, and meat.
Our portfolio of ultrasonic homogenizers and extractors ranges from hand-held, portable devices to fully-industrial production systems for the inline processing of large volumes on commercial scale.
Design, Manufacturing and Consulting – Quality Made in Germany
Hielscher ultrasonicators are well-known for their highest quality and design standards. Robustness and easy operation allow the smooth integration of our ultrasonicators into industrial facilities. Rough conditions and demanding environments are easily handled by Hielscher ultrasonicators.
Hielscher Ultrasonics is an ISO certified company and put special emphasis on high-performance ultrasonicators featuring state-of-the-art technology and user-friendliness. Of course, Hielscher ultrasonicators are CE compliant and meet the requirements of UL, CSA and RoHs.
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
|0.5 to 1.5mL
|1 to 500mL
|10 to 200mL/min
|10 to 2000mL
|20 to 400mL/min
|0.1 to 20L
|0.2 to 4L/min
|10 to 100L
|2 to 10L/min
|15 to 150L
|3 to 15L/min
|10 to 100L/min
|cluster of UIP16000
Contact Us! / Ask Us!
Literature / References
- Petigny L., Périno-Issartier S., Wajsman J., Chemat F. (2013): Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.). International Journal of Molecular Science 14, 2013. 5750-5764.
- Farid Chemat, Zill-e-Huma, Muhammed Kamran Khan (2011): Applications of ultrasound in food technology: Processing, preservation and extraction. Ultrasonics Sonochemistry, Volume 18, Issue 4, 2011. 813-835.
- Dogan Kubra, P.K. Akman, F. Tornuk(2019): Improvement of Bioavailability of Sage and Mint by Ultrasonic Extraction. International Journal of Life Sciences and Biotechnology, 2019. 2(2): p.122- 135.
- Casiraghi A., Gentile A., Selmin F., Gennari C.G.M., Casagni E., Roda G., Pallotti G., Rovellini P., Minghetti P. (2022): Ultrasound-Assisted Extraction of Cannabinoids from Cannabis Sativa for Medicinal Purpose. Pharmaceutics. 14(12), 2022.
- Alex Patist, Darren Bates (2008): Ultrasonic innovations in the food industry: From the laboratory to commercial production. Innovative Food Science & Emerging Technologies, Volume 9, Issue 2, 2008. 147-154.
- Allinger, H. (1975): American Laboratory, 7 (10), 75 (1975). Bar, R. (1987): Ultrasound Enhanced Bioprocesses, in: Biotechnology and Engineering, Vol. 32, Pp. 655-663 (1987).
- El’piner, I.E. (1964): Ultrasound: Physical, Chemical, and Biological Effects (Consultants Bureau, New York, 1964), 53-78.
- Kim, S.M. und Zayas, J.F. (1989): Processing parameter of chymosin extraction by ultrasound; in J. Food Sci. 54: 700.
- Mokkila, M., Mustranta, A., Buchert, J., Poutanen, K (2004): Combining power ultrasound with enzymes in berry juice processing, at: 2nd Int. Conf. Biocatalysis of Food and Drinks, 19-22.9.2004, Stuttgart, Germany.
- Moulton, K.J., Wang, L.C. (1982): A Pilot-Plant Study of Continuous Ultrasonic Extraction of Soybean Protein, in: Journal of Food Science, Volume 47, 1982.
- Mummery, C.L. (1978): The effect of ultrasound on fibroblasts in vitro, in: Ph.D. Thesis, University of London, London, England, 1978.
Facts Worth Knowing
Ultrasonic Cell Disintegration
Under intense sonication enzymes or proteins can be released from cells or subcellular organelles as a result of cell disintegration. In this case, the compound to be dissolved into a solvent is enclosed in an insoluble structure. In order to extract it, the cell membrane must be destructed. Cell disruption is a sensitive process, because the cell wall’s capability to withstand high osmotic pressure inside. Good control of the cell disruption is required, to avoid an unhindered release of all intracellular products including cell debris and nucleic acids, or product denaturation.
Ultrasonication serves as a well-controllable means for cell disintegration. For this, the mechanical effects of ultrasound provide faster and more complete penetration of solvent into cellular materials and improve mass transfer. Ultrasound achieves greater penetration of a solvent into a plant tissue and improves the mass transfer. Ultrasonic waves generating cavitation disrupt cell walls and facilitate the release of matrix components.
Ultrasonically Improved Mass Transfer Promotes Extraction
In general, ultrasound can lead to a permeabilization of cell membranes to ions, and it can reduce the selectivity of the cell membranes significantly. The mechanical activity of the ultrasound supports the diffusion of solvents into the tissue. As ultrasound breaks the cell wall mechanically by the cavitation shear forces, it facilitates the transfer from the cell into the solvent. The particle size reduction by the ultrasonic cavitation increases the surface area in contact between the solid and the liquid phase.
Ultrasonic Lysis and Inactivation of E.coli
To produce small amounts of recombinant proteins for the study and characterization of their biological properties, E.coli is the bacterium of choice. Purification tags, e.g. polyhistidine tail, beta-galactosidase, or maltose-binding proteins, are commonly joined to recombinant proteins in order to make them separable from cell extracts with a purity sufficient for most analytical purposes. Ultrasonication allows to maximize the protein release, in particular when the production yield is low and to preserve the structure and activity of the recombinant protein.
At controlled intensities, the application of ultrasound to biotransformation and fermentation may well result in an enhanced bioprocessing, due to induced biological effects and due to facilitated cellular mass-transfer. The influence of the controlled application of ultrasound (20kHz) on the oxidation of cholesterol to cholestenone by resting cells of Rhodococcus erythropolis ATCC 25544 (formerly Nocardia erythropolis) was investigated by Bar (1987).
This system is typical of microbial transformations of sterols and steroids in that the substrate and the products are water insoluble solids. Therefore, this system is rather unique in that both the cells and the solids may be subject to the effect of ultrasound. At a sufficiently low ultrasonic intensity which preserved the structural integrity of the cells and maintained their metabolic activity, Bar observed a significant enhancement in the kinetic rates of the biotransformation in microbial slurries of 1.0 and 2.5 g/L cholesterol when sonicated for 5s every 10mn with a power output of 0.2W/cm². Ultrasound showed no effect on the enzymatic oxidation of cholesterol (2.5g/L) by cholesterol oxidase.