Ultrasonic Homogenization of Soy Milk

  • The challenges of soy milk production lie in the production of a tasty, nutritional high-quality soy-based drink under high efficiency process conditions.
  • Ultrasonic homogenization and pasteurization offers the advantages of a healthy soy milk with high nutritional values & shelf-stable properties as well as high mechanical an microbiological stability.

Ultrasonically-Assisted Production of Soy Milk

The ultrasonic treatment of soy-base and soy milk modifies physicochemical properties (macromolecular changes, enzyme inactivation), gives a uniform, fine-size homogenization and improves the rheological characteristics. Ultrasonic emulsification results in a self stable plant milk, whilst ultrasonic preservation and inactivation of microorganisms ensures microbial stability. Besides the improvements of nutritional values, stability and flavour, sonication convinces by its energy- and time-efficiency. In comparison to conventional methods, the ultrasonic treatment is less energy-consuming and more time-efficient.
Ultrasonic homogenizers cover the full production capacity of soy milk production, result in optimized preservation and allow for a functional versatility of the production line. Ultrasonic inline homogenizers can be adjusted easily to the production targets allowing for the production of various flavour profiles (e.g. beany, non-beany) and product funcionality by simply changing the process parameters.

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Ultrasonic homogenizer for soy proteins and soy milk

Sonication is highly efficient to homogenize and preserve soy milk

Soy Flavours and the Effect of Ultrasound

Ultrasonic processing allows to influence the flavour of soybase: Soy milk products can produced with a strong beany flavour, which is appealing to the Asian customer target, whilst western consumers prefer a non-beany, smooth taste. By adapation of the ultrasonic process parameters (amplitude, sonication time, temperature, pressure), either a strong or mild flavour profile can be obtained. This means that the same ultrasonic system can be used to produce selectively various soy flavour profiles in order to manufacture various product types to please different target markets.

Ultrasonic Enzyme Inactivation

The intense soy-bean taste is related mainly to the activity of the lipoxygenase enzyme (LOX). The inactivation of this enzyme LOX is one of the major objectives of modern processing systems.
Manothermosonication (MTS) – the sonication under elevated pressure and temperature conditions – is a proven method to inactivate the lipoxygenase (LOX) enzyme. Lipoxygenase activity causes oxidation of fatty acids and pigments. Intense ultrasound waves cause the inactivation or denaturation of enzymes such as lipoxygenase, peroxidase and polyphenol oxidase.
MTS has been proved to be an efficient tool to inactivate some other enzymes, such as lipoxygenase, peroxidase, and proteases and lipases from psychrophilic bacteria. (Kuldiloke 2002: 2)

Advantages of Ultrasonic Soy Milk Production

  • high extraction yield
  • pleasant flavour
  • mechanical stability
  • microbiological stability / preservation
  • enzyme inactivation
  • energy-efficiency

Microbiological Stability by Ultrasonic Preservation

Ultrasound alone or in combination with heat (thermosonication) or pressure (manosonication) or both heat and pressure (manothermosonication) is known as an effective method to inactivate various food enzymes such as lipoxygenase, peroxidase, and polyphenol oxidase, as well as heat-resistant lipase and protease. Powerful ultrasound waves destruct microorganisms resulting in microbial inactivation and thereby microbial product stability. The inactivation of pathogenic and spoilage microorganisms or enzymes by sonication is mainly caused by physical (caviation, mechanical forces) and/or chemical effects.

Soy Protein Extraction and Isolation using Ultrasonics

Ultrasonic flow cells made from stainless steel and sanitary fittings are suitable for food processing.The application of power ultrasound to soy protein isolate (SPI) and soy protein concentrate (SPC) enables for a targeted modification of the soy protein to obtain a highly functional food additive. Manifold new product concepts involve the use of soy proteins as a base and ultrasonically assisted processing allows for the industrial manufacturing of superior quality products such as dairy-free, vegan smoothies, cheese alternatives, soy cream based soups, spreads and creamy dressings.
Sonication with a powerful ultrasonicator (e.g. UIP2000hdT) causes significant changes in conductivity, increases the solubility of soy protein concentrates, increases the specific surface area significantly, which is important for food textures, and increases the values of the emulsion activity index (EAI). Weight mean diameter D and volume–surface average diameter D decrease significantly for soy protein isolates (SPI) and soy protein concentrates (SPC).
In comparison to conventional soy protein treatments, sonication is less energy consuming and significantly more time-efficient.

Ultrasonic flow cells are used for particle size reduction as well as the extraction of nutritional compounds and flavour. This makes sonicators ideal for soy milk processing.

Ultrasonic flow reactors are highly efficient for extraction and homogenization, e.g. in soy-milk processing,

Ultrasonic Homogenizers for Soy Milk and Plant-Based Milk Substitutes

Hielscher Ultrasonics food processors are versatile and can be easily installed or retrofitted into existing production lines. High power, reliability and robustness make Hielscher sonicators the “work horse” in soybase production. Sonotrodes are made from titanium, ultrasonic reactors and other wet-parts are from food-grade stainless steel and can be equipped with sanitary fittings. This allows for the safe and reliable processing of food and beverage products.

Why Hielscher Ultrasonics?

  • high efficiency
  • state-of-the-art technology
  • reliability & robustness
  • adjustable, precise process control
  • batch & inline
  • for any volume
  • intelligent software
  • smart features (e.g., programmable, data protocolling, remote control)
  • easy and safe to operate
  • low maintenance
  • CIP (clean-in-place)

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:

Batch VolumeFlow RateRecommended Devices
10 to 2000mL20 to 400mL/minUP200Ht, UP400St
0.1 to 20L0.2 to 4L/minUIP2000hdT
10 to 100L2 to 10L/minUIP4000hdT
15 to 150L3 to 15L/minUIP6000hdT
n.a.10 to 100L/minUIP16000
n.a.largercluster of UIP16000

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Please use the form below, if you wish to request additional information about ultrasonic homogenization. We will be glad to offer you an ultrasonic system meeting your requirements.

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Industrial ultrasonic food processor for the production of ice cream in continuous flow mode.

Ultrasonic food processor UIP16000 for the industrial production plant-based milk substitutes.

Facts Worth Knowing

Soy Milk

Soy milk is a plant-based milk substitute, which is produced by extraction from whole soy beans in water. Soy milk is an emulsion of water and soy-derived lipids, which contains water soluble proteins and carbohydrates. For the old-fashioned, traditional way of soy milk preparation, soy beans were soaked, grinded, filtered and cooked. So prepared soy milk offers only a short self life. However, today’s consumers, and the modern lifestyle, request products with a longer shelf-life, which remain safe and stable during the complete storage period. For production of such soy milks and beverages utilization of the UHT technology is obvious. Hereby shelf-life from several months and up to a year can be obtained, depending on the composition of the product. Further, the right choice of emulsifiers and stabilizers is necessary for ensuring a homogeneous product without creaming and sedimentation during the entire shelf-life.

Production of Soy Milk and Soy-Based Drinks

Soy milk is made from whole soybeans or full-fat soy flour. The dry beans are soaked in water overnight or for a minimum of 3 hours or longer. The soaking time is heavily related on the temperature of the water. Afterwards, the soaked beans are ground in a wet-milling process. The water is added to rise the water content as required for the final soy milk product. The final soy drink features generally a protein content of 1–4% and the weight ratio of water to soyabeans 20:1 for a typical soy beverage that appeals to the Western consumers. (Traditional Asian soy milk has a water : soybean weight ratio of as high as 5:1). The milled soy bean slurry is boiled in order to improve flavour properties, digestibility, and microbial stability. The heat treatment inactivates soybean trypsin inhibitors, inactivates lipoxygenase for a milder flavor, and pasteurizes the soy milk. The heat treatment is applied for approx. 15–20 minutes, followed by filtration to remove insoluble residues such as soy pulp fibers / okara. Finally, the soy beverage can be artificially flavoured by adding of sugar, vanilla, chocolate, fruit or other flavours.

Soy Drinks and Yogurt

Soy beans are used to produce various products such as milk substitutes and soy drinks, juice, soy mix drinks (especially in Latinamerica) as well as soy yoghurt. Soy-based drinks and yogurts are widely consumed as dairy alternative by lactose intolerants and vegans, but consumers choose soy products for its health benefits and flavour, too.
Typical soymilk shows the following composition of approx. 3.6% protein, 2% fat, 2.9% carbohydrates and 0.5% ash. Soy beans have a low content of saturated fats, are cholesterol-free and lactose-free. Additionally, they have a high amount of vitamins and minerals make its consumption very health-beneficial.


Manothermosonication (MTS) is the synergetic combination of ultrasound with heat and pressure.


  • Mauricio A. Rostagno, Miguel Palma, Carmelo G. Barroso (2003): Ultrasound-assisted extraction of soy isoflavones. Journal of Chromatography A, Volume 1012, Issue 2, 2003. 119-128.
  • M. Morales-de la Peña, O. Martín-Belloso, J. Welti-Chanes (2018): High-power ultrasound as pre-treatment in different stages of soymilk manufacturing process to increase the isoflavone content. Ultrasonics Sonochemistry, Volume 49, 2018. 154-160.
  • Berk, Z. (1992): Soymilk and related products. Food and Agriculture Organization of the United Nations, Rome, Italy; Corporate Document Repository: Technology of Production of Edible Flours and Protein Products from Soybeans. Services Bulletin No. 97, Chapter 8. Retrieved 16 January 2017.
  • Bourke, P.; Tiwari, B.; O’Donnell, C.; Cullen, P. J. (2010): Effect of ultrasonic processing on food enzymes of industrial importance. Trends in Food Science and Technology, Vol. 21, Issue 7, 2010.

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