Ultrasonic Honey Processing

Honey enjoys great demand as food and medicine. Ultrasonic processing is an effective means to destroy undesirable components, such as crystals and microbial cells in honey. As a non-thermal processing technology, ultrasonic honey decrystallization prevents undesired increase in HFM as well as better retention of diastase, aroma and flavor.

Advantages of Ultrasonic Honey Decrystallization

Ultrasonic decrystallization is an efficient alternative to traditional heating methods for honey decrystallization. Ultrasonic honey decrystallization offers numerous advantages over the conventional heating method, which makes ultrasonic honey processing the superior treatment for honey liquefaction, decrystallization and stabilization:

  • Preservation of the Nutritional Values of Honey: Traditional heating methods involve exposing honey to high temperatures, which can degrade its nutritional value. Ultrasonic decrystallization operates at lower temperatures, minimizing the risk of heat-induced nutrient loss and preserving the natural honey enzymes, vitamins, and antioxidants.
  • Faster and More Efficient Process: Ultrasonic decrystallization can significantly reduce the time required to decrystallize honey compared to traditional heating methods. The application of ultrasonic waves creates cavitation bubbles in the honey, causing rapid and uniform heating throughout the entire volume. This leads to faster and more efficient decrystallization.
  • Uniform Dissolving and Decrystallization: Traditional heating of honey provides an uneven treatment since heat is applied to the honey mass in drums or barrels. This results in partially over-heated honey, whilst other parts of honey in the drum are barely reach a sufficient temperature increase in order to achieve dissolving of sugar crystals and microbial inactivation. Ultrasonic honey processing is applied in continuous flow so that the whole honey bulk is uniformly exposed to ultrasound. This results in a well-controlled liquefaction, decrystallization and stabilization treatment by sonication.
  • Improved Quality and Flavor: Heat can alter the flavor, color, and aroma of honey. Ultrasonic decrystallization, with its gentle heating approach, helps maintain the original sensory characteristics of the honey. It minimizes the risk of overheating, caramelization, or flavor degradation, resulting in a higher-quality end product.
  • Reduced Risk of HMF Formation: Hydroxymethylfurfural (HMF) is a compound that forms in honey when exposed to high temperatures. Excessive HMF levels indicate poor honey quality. Ultrasonic decrystallization, operating at lower temperatures, reduces the risk of HMF formation, ensuring the honey retains its natural composition and high quality.
  • Energy Efficiency: Traditional heating methods require significant energy consumption to raise the temperature of the honey to the desired level. Ultrasonic decrystallization, on the other hand, can achieve the same result with lower energy input due to its ability to generate localized and efficient heating within the honey.

    Ultrasonic decrystallization offers several advantages and can be adapted to all honey types and production scales. Hielscher ultrasonicators are precisely controllable and can be tuned to factors such as honey viscosity, crystal size, and quality standards. Thereby, Hielscher ultrasonicators provide high effectiveness and simple, safe operation.


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    Ultrasonic honey processing reactor for liquefaction and decrystallization of high-quality honey.

    Industrial ultrasonicator for the decrystallization and stabilization of honey in a highly uniform inline treatment.

    Power Ultrasound is a non-thermal method to dissolve sugar crystals in honey providing a mild decrystallization and liquefaction without deteriorating the honey quality.

    Microscopic images of treated honey:
    (a) Control sample. Before being treated, honey appears as network of needle-shaped crystals. Dark circles are air bubbles. (b) 40°C heat-treated samples after 20 min of thermal treatment; (c) 40°C+ ultrasound-treated samples after 20 min of treatment.
    (Research paper and image: ©Deora et al., 2013)

    Ultrasonic Honey Processing

    Ultrasonication is a non-thermal technique to liquefy honey. Ultrasound waves penetrate the honey and dissolve crystals.Ultrasonication is a non-thermal processing alternative for many liquid food products. Its mechanical power is being used for a gentle yet effective microbial inactivation and particle size reduction. When honey is exposed to ultrasonication, most of the yeast cells are destroyed. Yeast cells that survive sonication generally lose their ability to grow. This reduces the rate of honey fermentation substantially.
    Ultrasonication also liquefies honey eliminating existing crystals and inhibiting further crystallization in honey. In this aspect, it is comparable to heating the honey. Ultrasonically aided liquefaction can work at substantially lower process temperatures of approx. 35°C and can reduce liquefaction time to less than 30 seconds. Kai (2000) studied the ultrasonic liquefaction of Australian honeys (Brush box, Stringy bark, Yapunyah and Yellow box). The studies showed, that sonication at a frequency of 20kHz liquefied the crystals in the honey, completely. Ultrasonically treated samples remained in liquefied state for approx. 350 days (+20% when compared to heat treatment). Due to the minimal heat exposure, ultrasonic liquefaction results in a greater retention of aroma and flavour. Sonicated samples show only a very low HMF increase and small decrease in diastase activity. As less thermal energy is needed, the application of ultrasound helps to save processing costs when compared to conventional heating and cooling.

    Ultrasonic dissolving and microbial inactivation is used to improve honey quality. High.intensity ultrasound prevents crystallization, helps to reverse already formed crystals (decrystallization) and to inactivate unwanted microbes.

    Industrial ultrasonicator UIP6000hdT for the liquefaction and microbial stabilization of honey.

    The studies of Kai (2000) also revealed, that different types of honey require different intensities and times of sonication. For this reason, we recommend the conduct of trials using a bench-top size sonication system. Preliminary tests should be conducted in batch mode, while further processing trials require a flow cell for pressurized recirculation or in-line testing.

    What Research says about Ultrasonic Honey De-Crystallization

    Honey is a supersaturated solution of glucose and it has a tendency to crystallize spontaneously at room temperature in the form of glucose monohydrate. Heat treatment has been employed traditionally to dissolve D-glucose monohydrate crystals in honey and delay crystallisation. However, this approach negatively affects the fine-spun flavour of honey. The beneficial application of power ultrasound in honey has been reported by many researchers. The application of ultrasound has been shown to eliminate existing crystals and also retard the crystallisation process resulting in a cost-effective technology. Analysis of the crystallisation process suggests that sonicated honey samples remained in liquid state for longer periods than heat-treated honey. In addition, no significant effects on honey quality parameters, such as moisture content, electrical conductivity or pH, were observed. Studies have shown that, in general, ultrasound treatment (e.g. with a 24 kHz ultrasonic probe of the model UP400St, in batch treatment) leads to faster dissolution of crystals than thermal treatment.
    (cf. Deora et al., 2013)
    Basmacı (2010) compared ultrasonication and high-hydrostatic pressure as treatment options for honey liquefaction. Whilst the high-hydrostatic pressure treatment was shown as too expensive and ineffective, ultrasound gave very good results. Therefore, sonication was recommended as alternative for traditional thermal processing of honey.
    Önur et al. (2018) came to the same conclusion when comparing conventional heat treatment at 50ºC, ultrasonic liquefaction and They recommend ultrasonic honey processing over thermal processing and pressure treatment owing to the convenience, shorter processing times, and less quality loss.
    Sidor et al. (2021) compared ultrasonic liquefaction with microwave heating in order to dissolve sugar crystals in lime, acacia and multifloral honeys. A major disadvantage of the microwave heating were the significantly increased HMF values, changes in enzymatic activity and large diastase number losses. In contrast ultrasonic liquefaction resulted in only smallest changes in honey properties, so that the research team clearly recommended the ultrasonic honey processing in order to delay the crystallization process.
    accelerate the liquefaction time of solid honeys without compromising its quality.

    Ultrasonicator UIP2000hdT is a mobile overhead homogenizer for numerous liquid and solid-liquid applications.

    Overhead ultrasonicator UIP2000hdT with cascatrode on a mobile stand for honey liquefaction and sugar dissolving in batch and inline mode.

    High-Performance Ultrasonicators for Honey Decrystallization and Stabilization

    High-power ultrasound probe for industrial applications: The Hielscher Cascatrode™️Hielscher Ultrasonics manufactures and supplies high-performance ultrasonicators for liquid food processing such as honey liquefaction, crystal reduction (sugar dissolving, decrystallization) and microbial stabilization. Specially developed ultrasonic equipment for honey treatment allows for uniform and reliable processing. This assures the production of superior honey at maintained quality standards. For the treatment of honey, Hielscher Ultrasonics offers special sonotrodes (ultrasonic probes), which are ideal for the very uniform treatment of viscous liquids such as honey.

    Design, Manufacturing and ConsultingQuality 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.

    Why Hielscher Ultrasonics for Honey Processing?

    • high efficiency
    • state-of-the-art technology
    • reliability & robustness
    • batch & inline
    • for any volumefrom small batches to large flow per hour
    • scientifically proven
    • intelligent software
    • simple, linear scale-up
    • smart features (e.g., data protocolling)
    • CIP (clean-in-place)

    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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    Ask for more information

    Please use the form below to request additional information about ultrasonic honey liquefaction, ultrasonicators, technical data and prices. We will be glad to discuss your honey production with you and to offer you an ultrasonic honey liquefaction system meeting your requirements!

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    Ultrasonic high-shear homogenizers are used in lab, bench-top, pilot and industrial processing.

    Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers for mixing applications, dispersion, emulsification and extraction on lab, pilot and industrial scale.

    Literature / References

    Facts Worth Knowing

    Background of Honey Processing

    Honey is high viscosity product of characteristic flavour and aroma, color and texture.
    Honey consists of glucose, fructose, water, maltose, triaccharides and other carbohydrates, sucrose, minerals, proteins, vitamins and enzymes, yeast and other heat-resistant microorganisms and small amounts of organic acids (see chart below). High level of tetracyclines, phenolic compounds and hydrogen peroxide in honey give is antimicrobial properties.

    nutritional profile sugars honey

    Nutritional profile and sugar composition of honey (©www.honey.com)


    Honey Enzymes

    Honey contains starch digesting enzymes. Enzymes are sensitive to heat and therefore serve as an indicator of honey quality and degree of thermal processing. Major enzymes include invertase (α-glucosidase), diastase (α-amylase) and glucose oxidase. These are nutritionally important enzymes. Diastase hydrolyses carbohydrates for easy digestibility. Invertase hydrolyses sucrose and maltose to glucose and fructose. Glucose oxidase catalyses glucose to form gluconic acid and hydrogen peroxide. Honey does also contain catalase and acid phosphatase. The enzyme activity is generally measured as diastase activity and is expressed in a diastase number (DN). Honey standards specify a minimum diastase number of 8 in processed honey.

    Yeast and Microorganisms in Honey

    Extracted honey contains undesirable materials, such as yeast (generally osmophillic, sugar-tolerant) and other heat-resistant microorganisms. They are responsible for the spoilage of the honey during storage. A high yeast count leads to a rapid fermentation of honey. The rate of the fermentation of honey is also correlated to the water/moisture content. A moisture content of 17% is considered to be a safe level for retarding yeast activity. On the other hand, the chance of crystallization increases with decrease in moisture content. A yeast count of 500cfu/mL or less is regarded as a commercially acceptable level.

    Crystallization / Granulation in Honey

    Honey naturally crystallizes as it is a supersaturated sugar solution, with more than a 70% sugar content relative to a water content of about 18%. The glucose spontaneously precipitates out of the supersaturated state, through losing water as it becomes a more stable saturated state of glucose monohydrate. This leads to the formation of two phasesa liquid phase on top and a more solid crystalline form below. The crystals form a lattice, that immobilizes other components of the honey in suspension, thus creating a semisolid state (National Honey Board, 2007). Crystallization or granulation is undesirable as it is a serious problem in processing and marketing of the honey. Also, crystallization limits the flow of unprocessed honey out of storage containers.

    Heat-Treatment in Honey Processing

    After extraction and filtration, honey undergoes thermal-treatment in order to reduce the moisture level and to destroy yeast. The heating does help to liquefy crystals in the honey. Although, heat-treatment can effectively reduce moisture reduction, reduce and delay crystallization, and destroy yeast cells completely, it does also result in product deterioration. The heating increases the level of hydroxymethylfurfural (HMF) considerably. The maximum permissible statutory level of HMF is 40mg/kg. Furthermore, heating reduces enzyme (e.g. diastase) activity and affects sensory qualities and reduces the freshness of the honey. Heat processing darkens the natural honey color (browning), too. In particular heating above 90°C results in caramelization of the sugar. Due to uneven temperature transmission and exposure, heat-treatment falls short in the destruction of heat-resistant microorganisms.
    Due to the limitations of heat treatment, research efforts focus on non-thermal alternatives, like microwave radiation, infrared heating, ultrafiltration and ultrasonication. Ultrasonication offers as a non-thermal treatment great advantages in comparison to alternative honey processing techniques.

    High performance ultrasonics! The Hielscher product range covers the full spectrum from the compact lab ultrasonicator over bench-top units to full-industrial ultrasonic systems.

    Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers from lab to industrial size.

    We will be glad to discuss your process.

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