Superior Efficiency and Quality in Nutmilk Production with Ultrasonics
Nutmilks and plant-based milk alternatives are a growing food segment. For the production of nutmilks and plant-based milk analogues, ultrasonic extraction and homogenization has shown great advantages over conventional techniques. High-power ultrasound increases yield, product stability, nutrient content and overall processing efficiency.
Higher Nutmilk Yields with Power Ultrasonics
Ultrasonic extraction is well known as reliable and highly efficient method to increase the yield of plant-derived oils, proteins, polysaccharides, and micro-nutrients. Therefore, sonication is used in the production of plant-based milk substitutes, e.g. made from almond, cashew, coconut, hazelnut, peanut, sesame, soy, tiger nut, oat, rice, hemp, peas, pistachios, walnut, amaranth, or quinoa. The raw material of nutmilks and other plant-based milk alternatives is often expensive and higher extraction yields from these raw materials lowers production costs and improve production efficiency.
How Does Ultrasonic Extraction Increase Yield?
The working principle of ultrasonic extraction is acoustic cavitation. The extraction intensifying mechanism of low-frequency, high-intensity ultrasound is mainly attributed to the phenomenon of acoustic cavitation. When cavitation bubbles collapse on the surface of the botanical material, erosion and sonoporation breaks the matrix of plant cells (such as as macerated nuts, seeds, legumes, and leaves), which results in the destruction of the cellular structure and the release of intracellular substances such as proteins, lipids, polysaccharides, fibres, vitamins, minerals, and phytochemicals. The thereby intensified mass transfer facilitates the release of molecules such as proteins, lipids, polysaccharides and phyto-chemicals.
Ultrasonically generated shear forces improve the penetration of the solvent into the cellular matrix of the botanical matter and improve the permeability of the cell membranes, respectively. (Please note that the term solvent is used in a broad sense of meaning and includes any liquid, e.g., water). These mechanisms of power ultrasonics are responsible for the significant process intensification achieved when ultrasonication is applied for the extraction of food products from botanical raw material. As ultrasonic cavitation generates such intense forces, it drives highly effective cell disruption and mixing on macro- and micro-level. Furthermore, solvent penetration, the dissolving of bioactive compounds, and mass transfer are significantly improved. This makes ultrasound-assisted extraction highly efficacious, resulting in superior extract yields within a rapid process time.
Improved Nutmilk Stability with Ultrasonics
High-intensity, low-frequency ultrasonication is an efficacious and reliable method to improve the physical stability of suspensions as well as the microbial stability of food products (e.g., nutmilk and other milk substitutes).
Ultrasonically Improved Physicochemical Stability of Nutmilks
Widely used for homogenization and emulsification of food products, high-power ultrasound is a highly efficient non-thermal technique to produce highly homogeneous and long-term stable food products. Ultrasonic homogenization reduces the diameter of fat droplets to uniform minute size and disperses solid particles such as starches, sugars and fibres evenly. Thereby, ultrasonic homogenization improves the physicochemical of nutmilks and other plant-based milks significantly, so that unwanted phase separation is prevented.
Lu et al. (2019) investigates the effects of high-power ultrasonication on coconut milk. Sonication treatment reduced the particle size of the coconut milk and homogenized the distribution of droplets and solids in the system. In comparison to mechanically emulsified coconut milk, the ultrasonic treatment showed a significant effect on the uniform of emulsion system (p < 0.05). Additionally, it was observed that sonication promoted the encapsulation of amylose into the enzyme amylase in the interfacial layer. Iswarin and Permadi (2012) investigated how ultrasonication affects the droplet diameter of coconut-based milk drinks studying various combinations of ultrasonic intensity. Ultrasonic processing reduced the diameter of the droplet size and size reduction increased at higher ultrasound intensity.
Ultrasonically Improved Microbial Stability of Nutmilks
Ultrasonication has been proven to reduce the microbial load in dairy, fruit juices and other liquid foods. Therefore, ultrasonic pasteurization has been also adopted to the preservation process of milk alternatives in order to improve microbial stability in nut- and other plant-based milk substitutes.
Iorio et al. (2019) studied the ultrasonic inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in almond milk and could demonstrate the ultrasonic pasteurization causes sub-lethal damage to the pathogens, which leads to an increased shelf life. For instance, ultrasonic pasteurization treatment significantly reduced E. coli O157:H7 level from 5.12 to 3.81 log CFU/mL and lowered the growth rate (µmax) (from 1.19 to 0.79 (log CFU/mL)/day).
- Higher yields
- Superior quality
- Improved nutrient profile
- Physicochemical and microbial stabilization
- No thermal degradation
- Process intensification for higher overall efficiency
- Precisely controllable conditions
Higher Nutrient Content with Ultrasonic Nutmilk Extraction
Micronutrients such as vitamins, polyphenols and antioxidants are located within the cellular matrix of plants. To release these micronutrients efficiently, complete cell disruption and intense micro-mixing between cellular matter and solvent is required. As described above, ultrasonic extraction is very efficient in disintegration cells and releasing lipids, proteins, polysaccharides, fibres, and phytochemicals from the cellular matrix. Ultrasonic extraction is a highly efficient method to isolate the complete amount of phytochemicals from botanicals within a rapid extraction process. The application of high-power ultrasound produces strong cavitation effects, disturbances / turbulences, high-velocity liquid streaming, which wash the phytochemicals out of the cell interior. Being a non-thermal extraction method, thermal degradation of these sensitive micronutrients is prevented when using ultrasonication.
Superior Efficiency in Nutmilk Production with Ultrasonics
Higher yields, improved nutritional profile and reduced processing duration are just a few advantages when it comes to the superior efficiency of ultrasonic nutmilk and non-dairy beverage processing. Low energy consumption, low maintenance, and 24/7 operation are additional factors that contribute to the exceptional overall efficiency of ultrasonic processing. Hielscher high-performance ultrasonic homogenizers can run 24/7 under under heavy-duty and process high volumes in continuous flow mode. Hielscher ultrasonic processors have a n outstanding overall energy efficiency. Robustness and low maintenance keep operational costs low, too.
What Research says about Ultrasonic Food Processing
“Ultrasonic’s has emerged to an unconditional extent in the last decade. It has found its application in fruit juice and beverage industry due to its multifunctional desired effects. The technology is inexpensive, simple, reliable, and environmentally friendly and highly effective in the preservation of juices with enhanced quality attributes.” (Dolas et al., 2019)
“Sonication is an upcoming technology that can enhance food quality and reduce nutrient loss.” (Cheok et al., 2013)
Ultrasonic Food Processors for Industrial Nutmilk Production
Hielscher Ultrasonics designs, manufactures, and distributes high-performance ultrasonic food processing system for continuous industrial production of nutmilks (such as cashew, almond, hazelnut, walnut, peanut, coconut milk), and plant-based milk substitutes (such as rice, soy, spelt, oat, sesame, flaxseed, pea, fermented tiger nut milk).
The use of ultrasonic food processing offers major advantages being a non-thermal, purely mechanical method, which results in improved final products, decreases processing time, and is environmental-friendlier.
Hielscher ultrasonic food processing systems are used for manifold applications being a safe, reliable and cost-efficient technology to produce high-quality foods and beverages. Installation and operation of all Hielscher ultrasonic processors is simple: They requires only little space, can be easily retrofitted into existing processing facilities.
Hielscher Ultrasonics is long-experienced in the application of power ultrasound in the food & beverage industry as well as many other industrial branches. Our ultrasonic processors are equipped with easy-to-clean (clean-in-place CIP / sterilize-in-place SIP) sonotrodes and flow-cells (the wet parts). Hielscher Ultrasonics’ industrial ultrasonic processors can deliver very high amplitudes. Amplitudes of up to 200µm can be easily continuously run in 24/7 operation. High amplitudes are important achieve ahomogeneous particle distribution and to inactivate more resistant microbes (e.g., gram-positive bacteria). For even higher amplitudes, customized ultrasonic sonotrodes are available. All sonotrodes and ultrasonic flow cell reactors can be operated under elevated temperatures and pressures, which allows for a reliable thermo-mano-sonication (sonication in combination with elevated temperature and pressure) and highly effective extraction and stabilization.
State-of-the-art technology, high-performance and sophisticated software make Hielscher Ultrasonics’ reliable work horses in your food extraction, homogenization and pasteurization line. With a small footprint and versatile installation options, Hielscher ultrasonicators can be easily integrated or retro-fitted into existing production lines.
Please contact us know to learn more about the features and capability of our ultrasonic extraction, homogenization and pasteurization systems. We would be glad to discuss your application with you!
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
|Batch Volume||Flow Rate||Recommended Devices|
|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|
|n.a.||10 to 100L/min||UIP16000|
|n.a.||larger||cluster of UIP16000|
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Literature / References
- Tabib, Malak, Yang Tao, Christian Ginies, Isabelle Bornard, Njara Rakotomanomana, Adnane Remmal, Farid Chemat (2020): A One-Pot Ultrasound-Assisted Almond Skin Separation/Polyphenols Extraction and its Effects on Structure, Polyphenols, Lipids, and Proteins Quality. Applied Sciences 10, no. 10: 3628.
- Iswarin, S.J.; Permadi, B. (2012): Coconut milk’s fat breaking by means of ultrasound. Int. J. Basic Appl. Sci. 12, 2012. 1–5.
- Maria Clara Iorio, Antonio Bevilacqua, Maria Rosaria Corbo, Daniela Campaniello, Milena Sinigaglia, Clelia Altieri (2019): A case study on the use of ultrasound for the inhibition of Escherichia coli O157:H7 and Listeria monocytogenes in almond milk. Ultrasonics Sonochemistry, Volume 52, 2019. 477-483.
- Rupali Dolas, Chakkaravarthi Saravanan, Barjinder Pal Kaur (2019): Emergence and era of ultrasonic’s in fruit juice preservation: A review. Ultrasonics Sonochemistry, Volume 58, 2019.
- Xu Lu, Jinghao Chen, Mingjing Zheng, Juanjuan Guo, Jingxuan Qi, Yingtong Chen, Song Miao, Baodong Zheng (2019): Effect of high-intensity ultrasound irradiation on the stability and structural features of coconut-grain milk composite systems utilizing maize kernels and starch with different amylose contents. Ultrasonics Sonochemistry Volume 55, 2019. 135-148.
Facts Worth Knowing
Production of Nutmilks and Plant-Based Dairy Substitutes
The production of nutmilks and other plant-based, non-dairy beverages (e.g., from almond, cashew, coconut, hazelnut, peanut, sesame, soy, tiger nut, oat, spelt, rice, hemp, pea, flaxseed, linseed, walnut) includes commonly the following processing steps: wet milling and grinding for extraction, filtration, the addition of food additives and ingredients, pasteurization / sterilization, homogenization, and aseptic packaging.
widely used additives are gums and lecithin, which are used to improve stability, as well as salt and sweeteners, which are used to modify texture and flavour profile. Often plant-based milk substitutes are fortified and enriched with protein, vitamins and minerals to obtain a balanced nutritional profile of the plant-based non-dairy beverage.
Depending on the type of plant-based milk substitute, a different raw ingredient (e.g., nuts, grains, legumes) is used as base. This specific raw material (e.g., almonds, soy beans or oats) are mixed with a certain amount of water and milled in a wet-grinding process under elevated temperatures. During this heated milling process, valuable plant compounds such as proteins, lipids, fibres and vitamins are extracted from the raw material, which is time-consuming and often quite inefficient. Due to the incomplete extraction, a second extraction step may be necessary to increase the yield of the nutmilk or plant-based milk substitute. When ultrasonic extraction is implemented in the milling process, the extraction of plant compounds is significantly increased and accelerated.
After the milling and extraction, the plant milk is separated from the extracted plant fibers in large centrifuges. In order to improve texture and sensory qualities, the plant milk may be homogenized with edible oil or thickened by adding gums, mixed with various addititives (vitamins, minerals), and is finally pasteurized by heat treatment and then packaged.
Sonication can be used to disperse gums and other food additives homogeneously in the plant based beverage and promote the microbial stabilization by ultrasonic pasteurization.