Faster Sprouting with Ultrasonics

Sprouts are a popular health food rich in vitamins, proteins, minerals and antioxidants. The sprouting process is laborious and time-consuming. Ultrasonic activation of seeds increases the germination rate, accelerates the sprouting process, improves the nutritional profile, and promotes the growth of healthy seedlings. Ultrasonic steeping and priming of seeds is the ideal technique to increase your sprouting capacities.

Sprouting Seeds, Grains and Legumes

Ultrasonic seed activation improves the germination and sprouting of cereals, legumes and microgreens.Sprouts are germinated seeds of alfalfa, clover, sunflower, broccoli, mustard, radish, garlic, dill, pumpkin, almonds, cereals (e.g., wheat berries, quinoa, barley, rye, buckwheat, sorghum, millet), legumes (e.g., peanuts, peas, chickpeas, lentils) as well as of various beans, such as mung, kidney, pinto, navy, and soy. Since sprouts are rich in phytonutrients such as proteins, vitamins, minerals and antioxidants and low in calories, fat and sodium, they are widely considered as “health food” and “superfood”. Including sprouts into the daily nutrition plan, helps to nourish the body with fibre, vitamins, minerals, and other health-promoting phytonutrients.
Bioavailability of nutrients in sprouts and microgreens: Cereals and legumes contain various anti-nutrients, which impede digestion and inhibit the bioavailability of micronutrients and minerals. For instance, trypsin inhibitors and phytates, which are present in cereals and legumes, reduce protein digestibility and mineral uptake, respectively. Trypsin inhibitors hinder the activity of the digestive enzyme trypsin, so that consequently ingested proteins cannot be digested properly and absorbed by the body.
Therefore, germination and sprouting are applied to deactivate these anti-nutrients. During sprouting, pathways for the production of nutrients and phytochemicals are initiated and enzymes are activated. By that means, sprouted seeds and legumes provide a wide spectrum of bioaccessible nutrients.
During the germination and sprouting procedure, endogenous enzymes such as α‐amylase, pullulanase, phytase, and other glucosidases get activated in the seeds. These enzymes degrade anti-nutritional factors and break down complex macronutrients into simple and more digestible forms.
Sprouts are full of health-promoting nutrients such as proteins, chlorophyll, vitamins, minerals, enzymes, amino acids and phyto-chemicals. For instance, broccoli sprouts are well known to be extremely rich in sulfurophane. Compared to mature broccoli florets, sprouted broccoli seeds contain 50 times more sulfurophane.

Sprouting Procedure

The cultivation of sprouts is laborious and time-consuming. During the sprouting process, hygiene and sanitary conditions are crucial to prevent microbial contamination and spoilage. Ultrasonically assisted soaking, germination and sprouting accelerates the cultivation and growth of nutrient-rich, vigorous sprouts and seedlings.

Enhanced Cultivation of Sprouts and Microgreens with Ultrasonics

Ultrasonic steeping, germination and sprouting intensifies your cultivation process of sprouts and micro-greens. Sprouting is a laborious and time-consuming process, which is prone to spoilage by mould and bacteria. As the seeds spend a significant amount of time in water (during the stage of soaking and steeping) and in a highly moist environment (during the stage of sprouting), the risk of microbial contamination and spoilage is very high. When spoiled sprouts and micro-greens are consumed, they cause severe food poisoning. Ultrasonic steeping and germination reduces the soaking and sprouting duration. As the seeds germinate and grow faster, the time of presence in high moisture environments is reduced. By that means, the time for microbial growth and spoilage is minimized. Ultrasonic sprouting not only makes your sprouting process more efficient, it also reduces the risk of contamination.
Furthermore, various research studies have shown that ultrasonically soaked and germinated sprouts excel by an elevated nutritional profile such as higher protein, vitamin and phytonutrient content when compared to conventionally sprouted seeds. Ultrasonically grown sprouts exhibit a higher seedling vigor, too.

The UP400St is a 400W powerful ultrasonic homogenizer for seed priming, germination and sprouting.

Ultrasonicator UP400St for seed priming. Ultrasonic treatment results in faster sprouting, higher nutrient profile and improved seedling vigor.

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Ultrasonically treated lentils show a higher water uptake.

Ultrasonic hydro-priming improves the water and nutrient uptake. The comparison of sonicated lentils (40Ws/g) vs non-sonicated lentils shows that sonication improves the water uptake significantly.

Ultrasonic Seed Activation

Ultrasonically intensified germination is caused by the mechanical effects of ultrasonic / acoustic cavitation. The effects of ultrasonic cavitation impact the seed shell: It fragments the seed coat and creates thereby a larger porosity of the surface of seeds. It literally means that ultrasonic fragmentation of the seed coating perforates the shell. Furthermore, sonication enlarges the pore size so that a higher mass transfer between seed core and the growth medium takes place. The intensified mass transfer provides the seed with water and nutrients required. Due to the increased porosity and permeability, the seed can take up water and nutrients quicker. The better hydration and increased water retention capacity in dry seeds / grains result in accelerated growth of the sprouts.

The duration of ultrasonic seed treatment takes only a few minutes. The specific sonication duration depends on the hardness of seed coat and might wary between 4 to 6 minutes for most seed varieties. To adapt the ultrasonic treatment to the specific seed / grain type, the amplitude of the ultrasonicator is an important factor that contributes significantly to the effectiveness of the ultrasonic soaking and priming of the seeds. The harder and thicker the seed shell, the higher amplitudes are required. Hielscher Ultrasonics has profound knowledge of ultrasonically-assisted soaking /steeping, priming and germination of seeds. We will offer you the most suitable and effective ultrasonic equipment for your sprout varieties and sprouting capacities.

Ultrasonic seed priming

Longer sonication results in the better germination of the Calanthe hybrids. (Shin et al. 2011)

Higher Nutritional Value of Ultrasonically Germinated Sprouts

Ultrasonically assisted sprouting not only promotes germination speed and elicitation rate, but has also positive effects on the nutritional quality of sprouts. Several studies demonstrated an enhanced biosynthesis of phytonutrients by ultrasonication. Yang et al. (2015) measured increased isoflavonoid contents in sonicated soybean sprouts. Increased amounts of the isoflavoonoids daidzein and genistein by 39.13 and 96.91 %, respectively, when compared with the non-sonicated samples. The ultrasonically primed soy beans also showed elevated gamma-aminobutyric acid (GABA) by 43.4%. In another study, Yu et al. (2016) observed improved antioxidant capacity with ultrasonically treated Romaine lettuce.
Ampofo (2020) showed in her thesis that sonication of common beans at 360 W for 60 min provoked a significantly increased accumulation of stress markers at 96 h of sprouting. Stress during seedling growth leads to elevated activities of defense phenylpropanoid triggering enzymes, phenolic compounds and antioxidant capacities at significant levels in comparison to the non-sonicated control sample. The ultrasonication reduced sprouting time by 60 h, compared to the control. Ultrasonically treated seeds showed radicles emergence at 24 h of sprouting with significant radicle elongation at increasing sprouting times, whereas in comparison the control samples had delayed radicle emergence up to 48 h of sprouting. In respect to nutritional value, the sonicated bean sprouts showed a 6.6 fold higher total flavonoids content and an 11.57 fold higher total anthocyanin content when compared to non-sonicated samples.
Hielscher Ultrasonics’ probe ultrasonicators are precisely controllable. Process parameters auch as amplitude and temperature control as well as the uniform and even exposure of all seeds to the ultrasonic cavitation zone are essential factors in order to provoke up-regulated biosynthesis in seeds and sprouts.

Advantages of Ultrasonically-Promoted Sprouting

  • Reduced pre-soaking
  • Faster germination
  • More uniform growth
  • Enhanced nutrient uptake
  • Increased seedling vigor
  • Higher nutritional value of the sprouts
  • Faster turnover
  • Reduced risk of mirobial spoilage
  • Food-grade process
  • Simple and safe to operate
The SonoStation is a complete ultrasonic setup, which is suitable to process larger volumes of hand sanitizer.

SonoStation – a simple turnkey solution for ultrasonic processes

Case Studies of Ultrasonic Sprouting

Hassan et al. (2020) demonstrate that ultrasonically sprouted sorghum seeds show a significantly improved nutritional profile. Profile and amount of phytonutrients in sorghum seeds were enhanced by ultrasonication. Various phytochemical constituents (alkaloids, phytates, saponins, and sterols), radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl assay, ferric reducing antioxidant power assay, and oxygen radical absorbance capacity assay assay), phenolic profile (total phenolics content, total flavonoids content, ferulic acid, gallic acid, catechin, quercetin, and tannin) along with in vitro protein digestibility (IVPD %) were examined for the influence of ultrasonic germination of sorghum sprouts. All tested factors were improved by ultrasonic treatment. The treated sprouts exhibited especially high radical scavenging activity and a rich phenolic profile with higher percentage of IVPD.
Mild sonication treatment at 40% amplitude for 5 min showed the significant improvements. After germination, the ultrasound-treated sorghum sprouts showed superior profile of phytochemicals that can serve as valuable raw material for producing high-protein functional foods with low cost.

The UIP1000hdT is Hielscher's powerful 1kW ultrasonic processor for batch and continuous sonication (Click to enlarge!)Petru et al. (2018) investigated the action of ultrasonic cavitation during the collapse of cavitation bubbles. They found that ultrasonic cavitation induces micro-erosions on the seed coats, which increase the permeability of the seed shell and promotes mass transfer. They studied the influence of ultrasonic treatment for seed germination, emergence and initial stages of growth of triticale (rye and wheat hybride) seedlings. The samples of 50 seeds were treated by ultrasound in water in the following regime: the amplitude 15 µm at a temperature of 25 degС for different treatment durations 0, 2, 4, 6, 8 min. Then the seeds were placed for germination and sprouting on a wet filter paper at room temperature. The most pronounced effect of US treatment was observed for the treatment duration of 4 min. The optimal data on the germination of ultrasonically treated within 4 min triticale seeds and emergence of seedlings in comparison with the untreated seeds (control) are shown in Fig. 1. It was found out that the average length of the seedlings of the ultrasonically treated seeds by 15 – 20% exceeds the length for the control seeds. The ultrasonically treated seeds germinate earlier and exhibit greater germination vigor, higher length of seedlings and roots.

Ultrasonic Processors for Intensified Germination and Sprouting

Hielscher Ultrasonics’ high-performance processors are used in food and agriculture to promote germination and sprouting, seed-priming including osmo-priming, hydro-priming as well as fermentation processes. State-of-the art technology, user-friendliness, safe-to-operate and robustness are key features of all Hielscher Ultrasonics’ processors.

Batch and Inline

Hielscher ultrasonicators can be used for batch and continuous flow-through processing. Depending on your process volume and hourly throughput, inline processing might be recommended. Whilst batching of large volumes is more time- and labour-intensive, a continuous inline sonication process is more efficient, faster and requires significantly less labour.

Ultrasonic Processors for Every Production Capacity

Ultrasonic processor UIP4000hdT, a 4kW powerful ultrasonic reactorHielscher Ultrasonics product range covers the full spectrum of ultrasonic processors from compact lab ultrasonicators over bench-top and pilot systems to fully-industrial ultrasonic processors with the capacity to process truckloads per hour. The full product range allows us to offer you the most suitable ultrasonic processor for your process capacity and goals.
Ultrasonic benchtop systems are ideal for feasibility tests and process optimization. Linear scale-up based on established process parameters makes it very easy to increase the processing capacities from smaller lots to fully commercial production. Up-scaling can be done by either installing a more powerful ultrasonic mixer unit or clustering several ultrasonicators in parallel. With the UIP16000, Hielscher offers the most powerful ultrasonic processor worldwide.

Precisely Controllable Amplitudes for Optimum Results

All Hielscher ultrasonicators are precisely controllable and thereby reliable work tools. The amplitude is one of the crucial process parameters that influence the efficiency and effectiveness of ultrasonic germination and sprouting. Seeds with a soft coating require a mild sonication treatment and lower amplitude settings, whilst seeds with a robust and hard shell show better sprouting results when sonicated at higher amplitudes. All Hielscher Ultrasonics’ processors allow for the precise setting of the amplitude. Sonotrodes and booster horns are accessories that allow to modify the amplitude in an even wider range. Hielscher’s industrial ultrasonic processors can deliver very high amplitudes and deliver the required ultrasonic intensity for demanding applications. Amplitudes of up to 200µm can be easily continuously run in 24/7 operation.
Precise amplitude settings and the permanent monitoring of the ultrasonic process parameters via smart software give you the possibility to treat your seeds with the most effective ultrasonic conditions. Optimal sonication for best sprouting results!
The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation at heavy duty and in demanding environments. This makes Hielscher’s ultrasonic equipment a reliable work tool that fulfils your processing requirements.

Easy, Risk-free Testing

Ultrasonic processes can be completely linear scaled. This means every result that you have achieved using a lab or bench-top ultrasonicator, can be scaled to exactly the same output using the exactly same process parameters. This makes ultrasonication ideal for risk-free feasibility testing, process optimization and subsequent implementation into commercial manufacturing. Contact us to learn how sonication can increase your sprout yield and quality.

Highest Quality – Designed and Manufactured in Germany

As a family-owned and family-run business, Hielscher prioritizes highest quality standards for its ultrasonic processors. All ultrasonicators are designed, manufactured and thoroughly tested in our headquarter in Teltow near Berlin, Germany. Robustness and reliability of Hielscher’s ultrasonic equipment make it a work horse in your production. 24/7 operation under full load and in demanding environments is a natural characteristic of Hielscher’s high-performance ultrasonicators.

You can buy Hielscher ultrasonic processor in any different size and exactly configured to your process requirements. From treating seeds in a small lab beaker to the continuous flow-through mixing of seed slurries on industrial level, Hielscher Ultrasonics offers a suitable ultrasonicator for you! Please contact us – we are glad to recommend you the ideal ultrasonic setup!

The table below gives you an indication of the approximate processing capacity of our ultrasonicators:

Batch VolumeFlow RateRecommended Devices
1 to 500mL10 to 200mL/minUP100H
10 to 2000mL20 to 400mL/minUP200Ht, UP400St
0.1 to 20L0.2 to 4L/minUIP2000hdT
10 to 100L2 to 10L/minUIP4000hdT
n.a.10 to 100L/minUIP16000
n.a.largercluster of UIP16000

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Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers for dispersion, emulsification and cell extraction.

High-power ultrasonic homogenizers from lab to pilot and industrial scale.

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Facts Worth Knowing

Why does Sprouts contain More Nutrients?

Sprouting and germination are steps in the growth of a plant, in which many biochemical pathways are activated to initiate the start of the growth and to promote the development of a healthy, survivable plant. These biochemical pathways include the activation of manifold enzymes. Via biosynthesis, secondary metabolites (a.k.a. phyto-chemicals) are formed by enzymatic conversion. These secondary metabolites are known as health-promoting. Prominent examples include polyphenols, terpenes, sulfuraphane, and numerous others.
One example for such biosynthesis is the enzyme phenylalanine ammonia-lyase (PAL). The PAL enzyme catalyzes the pathways for biosynthesis of the different phyto-chemicals. When this enzyme is inhibited, it becomes limiting factor for biosynthesis of phenolic acids and flavonoids. A possible explanation for higher phytochemical contents in sprouts ist that PAL activity is up-regulated during germination. Alternative explanations suggest that bound phenolic compounds are hydrolysed aand/or that de novo biosynthesis of phenols in the embryonic axis of the sprouts occurs. Many phytochemicals are known for their anti oxidative characteristics, which explains an increased antioxidant activity of germinated cereals and legumes.
High in phytonutrients, sprouts are a great addition to the meal plan. Phytonutrients contribute to many pathways in the human body and can thereby prevent and/or ameliorate diseases.

Research has found various nutritional benefits for sprouting and germinating seeds, grains and legumes:

  • For buckwheat, after 72hr of germination a significantly increased protein content was found. Furthermore, germinated buckwheat had increased amounts of total phenolics, flavonoid, and condensed tannin (Zhang et al., 2015).
  • In germinated finger millet, the protein digestibility was increased by 64%. (Mbithi-Mwikya et al. 2000)
  • For white maize kernels, when sprouted for 5 days bioavailable phenolic compounds were increased by 92%.

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