Ultrasound In The Food Industry
The application of power ultrasound is used for numerous application in food processing, including extraction, homogenization, pasteurization and fermentation. As a non-thermal treatment, ultrasonication improves food production processes by higher yields, higher quality, improved nutrient and flavour profiles as well as time- and cost-saving processing.
Ultrasonic Applications in Food Processing
Power ultrasound has a wide range of applications in food processing, including extraction, mixing, emulsification, pasteurization, degasssing and meat tenderization. Besides these main applications, power ultrasound is also applied to improve freezing, thawing and drying of food products.
The major advantages of high-intensity ultrasonics are related to the improvement of various food processing operations, such as reducing processing time, increasing yields, improving product quality and allow for more cost- and time-saving, economical processing.
In the following paragraph, you can find the main applications of high-intensity ultrasonics in the food industry:
- Extraction: Ultrasound can be used to extract bioactive compounds from plant materials, such as antioxidants, pigments, and essential oils. This process is known as sonication-assisted extraction and can be used to produce high-quality extracts in a shorter time and with lower solvent consumption than traditional methods.
- Homogenization and Emulsification: Ultrasonic homogenization can be used to produce stable emulsions and suspensions, such as salad dressings, mayonnaise, creams, and dairy products. The process involves using high-frequency sound waves to break down the fat globules in the liquid, resulting in a smooth and uniform texture.
Find the step-by-step instruction and a video for ultrasonic mayonnaise emulsification here! - Preservation: High-intensity ultrasound can be used to inactivate microorganisms, such as bacteria and yeasts, in food products. The process, known as sonication-assisted pasteurization, can extend the shelf life of food products and reduce the risk of foodborne illnesses. As a non-thermal processing technique, sonication avoids the use of very high temperatures thereby preventing the related degradation of heat-sensitive nutrients.
Ultrasonic homogenizers are widely used in food processing. Typical applications include extraction, mixing, emulsification and ageing / maturation.
- Degassing: With the application of ultrasound to a liquid, gas bubbles entrapped in liquids are agitated. As a consequence, these air and gas bubbles come close to each other and coalesce. Theis means they grow to a larger bubble size which enables them to float to the top of the liquid and can be easily removed.
- Dissolving: Due to its outstanding mixing and blending capabilities, ultrasound is highly effective to produce highly saturated and even supersaturated solutions. This is used in crystallization processes as well as in the production of brines.
- Fermentation: As ultrasound waves perforate and break down the cell walls of the microorganisms, they get more susceptible to the fermentation process. At the same time, ultrasound accelerates the transport of nutrients and oxygen to the microorganisms, thereby enhancing their metabolic activity. Overall, ultrasonication increases the rate of fermentation, reduce fermentation time, and improve the yield of the desired end-product. This technology is particularly useful for the production of food and beverage products, such as dairy, yogurt, beer, kombucha, and wine.
- Viscosity Reduction before Spray Drying: Ultrasonic shear forces can reduce the viscosity in shear-thinning and thixotropic slurries significantly. Applying ultrasonic shear-thinning before spraying and spray dryers allows to increase the through-put through the spraying equipment significantly. Spray-drying towers are often the bottle-neck in production line. With ultrasound, the capacity of existing spray-dryers can be increased.
The closed batch reactor made from stainless steel is equipped with the ultrasonicator UIP2000hdT (2kW, 20kHz).
- Freezing: Ultrasonic freezing can be used to reduce the formation of ice crystals in food products during the freezing process. The process involves subjecting the food to high-frequency sound waves while it is being frozen. Ultrasound waves create vibrations that prevent the formation of large ice crystals, resulting in a product with a smoother texture and better quality.
- Thawing: Ultrasonic thawing can be used to reduce the thawing time of frozen food products. The process involves subjecting the frozen product to ultrasound waves, which generate heat and accelerate the thawing process. Since ultrasound promotes a very uniform distribution of energy, ultrasonic thawing can be particularly useful for products that are difficult to thaw evenly, such as meat, seafood, fruits and vegetables.
In freezing, thawing and drying, power ultrasound causes significant improvements in mass and energy transfer processes, which accelerates these processes and make them more economical. - Bottle Leak Detection: Ultrasound is a very efficient way to detect leaks and cracks in bottles and cans of carbonic beverages such as soda, beer, sparkling wine etc. Ultrasonics is also applied in the degassing of carbonated beverages, e.g., beer before bottling, a process known as de-fobbing.
- Brining / Pickling: Brining is common process in the preservation and manufacturing of foods, especially for meat, fish, cheese and vegetables. Ultrasonication shortens the brining time and allows to use reduced amounts of sodium chloride in comparison to traditionally brined foods and pickles.
- Hydration / Rehydration: Power ultrasound is a simple, yet highly effective method to hydrate or re-hydrate food products such as dried pulses (e.g. beans, chickpeas) or dehydrated mushrooms. Since ultrasound opens cellular pores in food, water can penetrate quickly. This leads to accelerated swelling of pulses and subsequently a shorter cooking time.
- Decrystallization of Honey: As a non-thermal treatment, ultrasound is effectively used to prevent the formation of large sugar crystals in honey. Furthermore, already formed large crystals in honey can be decrystallized by ultrasound treatment. As highly effective dissolving technique, probe-type ultrasonicators dissolve sugar crystals resulting in a uniformly smooth honey. Additionally, ultrasound improves the microbiological quality of honey since unwanted microbes are inactivated due to the effect of ultrasonic cell disruption.
- Frying: Ultrasonic frying can be used to reduce oil absorption in fried food products. The process involves immersing the meat or vegetable in hot oil while subjecting it to high-frequency sound waves. The ultrasound waves create small bubbles on the surface of the food, which reduce the contact area between the vegetable / meat and the oil, resulting in less oil absorption and a healthier final product. Ultrasonic frying allows to cook food at lower temperatures creating superior flavour profiles, preserving nutrients.
Learn how ultrasonically-assisted frying produces healthier, more flavourful, crispier French fries and potato chips!
High-Performance Ultrasonicators for Food Processing
Hielscher Ultrasonics industrial ultrasonic processors are high-performance ultrasonicators, which are precisely controllable and allow thereby for reproducible outcomes and continuous product quality. Being capable to deliver very high amplitudes, Hielscher ultrasonic processors can be used for very demanding applications.
Customers are satisfied by the outstanding robustness and reliability of Hielscher Ultrasonics systems. Hielscher ultrasonicators reliably run in fields of heavy-duty application, demanding environments and 24/7 operation and ensure thereby efficient and economical food processing. Ultrasonic process intensification reduces processing time and achieves better results, i.e. higher quality, higher yields, novel products.
By means of consistent application of special materials, as e.g. titanium, stainless steel, ceramic or glass of different grades, the compatibility of the technique with the process is guaranteed.
Ultrasonic processors are operator-friendly and convenient machines with low maintenance and a relatively low cost.
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
| Batch Volume | Flow Rate | Recommended Devices |
|---|---|---|
| 0.5 to 1.5mL | n.a. | VialTweeter | 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 |
| 15 to 150L | 3 to 15L/min | UIP6000hdT |
| n.a. | 10 to 100L/min | UIP16000 |
| n.a. | larger | cluster of UIP16000 |
Contact Us! / Ask Us!
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.
Facts Worth Knowing
How Does Ultrasonics in Food Processing Work?
Ultrasonic food processing is a well established technology used for food processing applications such as mixing and homogenization, emulsification, extraction, dissolving, degassing & deaeration, meat tenderisation, crystallization as well as functionalization and modification of intermediates and final food products. Being installed a since decades in food production plants, Hielscher ultrasonic food processors are sophisticated and developed to meet the industry requirements. Ultrasonic processors apply physical forces created by power ultrasound waves, which results in the generation of cavitation.
What is Acoustic Cavitation?
Acoustic cavitation, also known as ultrasonic cavitation, is the growth and collapse of minute vacuum bubbles in an ultrasonic field generated in liquids or slurries. The cavitation bubbles grow during the alternating high-pressure / low-pressure cycles, which are compression and rarefaction phases respectively. After having been grown over several alternating pressure cycles, the vacuum bubble reaches a point where it cannot absorb more energy so that the bubble implodes violently during a high-pressure cycle. During the bubble collapse, locally extreme conditions occur including extreme temperatures of up to 5,000K with very high heating and cooling rates, pressures of up to 2000atm and corresponding pressure differentials, and liquid jets with up to 280m/s velocity. In these cavitational “hot-spots”, locally extreme forces create physical conditions, which result in mixing, extraction and increased mass transfer.
Acoustic cavitation, generated by high-intensity, low-frequency ultrasound, creates intense shear forces and locally occurring high pressure and temperature differentials, which provide the necessary impact for intense mixing and mass transfer. These ultrasonic shear forces are successfully applied for food processing.
Literature/References
Ultrasonic homogenizer UIP6000hdT installed in a food processing plant.
Ultrasonic extraction of botanicals with the ultrasonicator UP400St
From feasibility testing to process optimization and industrial installation – Hielscher Ultrasonics is your partner for successful ultrasonic processes!