Ultraääniuutto ja säilyttäminen

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)

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.

Suunnittelu, valmistus ja konsultointi – Laatu valmistettu Saksassa

Hielscher-ultraääniastiat ovat tunnettuja korkeimmista laatu- ja suunnittelustandardeistaan. Kestävyys ja helppokäyttöisyys mahdollistavat ultraäänilaitteidemme sujuvan integroinnin teollisuuslaitoksiin. Hielscher-ultraäänilaitteet käsittelevät helposti karkeita olosuhteita ja vaativia ympäristöjä.

Hielscher Ultrasonics on ISO-sertifioitu yritys ja painottaa erityisesti korkean suorituskyvyn ultraäänilaitteita, joissa on huipputeknologia ja käyttäjäystävällisyys. Tietenkin, Hielscher-ultraäänilaitteet ovat CE-yhteensopivia ja täyttävät UL: n, CSA: n ja RoHs: n vaatimukset.

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