Ultrasonic Extraction of Sugar from Sugar Beet Cossettes
Ultrasonic extraction enhances the yield of extracted sucrose from sugar beet cossettes and reduces the extraction process duration significantly. Sonication is a simple and safe technique, which can be easily combined with the current counter-current flow extraction technology in order to improve extraction efficiency.
Ultrasonic Sugar Beet Cossette Extraction
Ultrasound-assisted extraction is based on the working principle of acoustic or ultrasonic cavitation. The mechanical effects, which are generated by ultrasonically induced cavitation, cause sono-poration and disruption of cell walls, which subsequently increases the permeability of molecules entrapped in the cell interior. Cavitationally caused liquid streaming and micro-turbulences improve the mass transfer of the extraction process, so that sucrose and other molecules are transferred into the solvent, i.e. water.
Ultrasonic extraction can be installed at various steps during sucrose extraction:
- Ultrasonic pre-treatment (before counter-current tower)
- Sonication during countercurrent extraction
- Ultrasonic post-treatment (after counter-current tower)
Depending on the existing extraction facility, production targets and available space, sonication can be easily retro-fitted as pre- or post-treatment as well as during countercurrent flow extraction.
Ultrasonic Pre-Treatment of Sugar Beet Cossettes
Ultrasonic pre-treatment of sugar beet cossettes is a process intensifying technique. Ultrasonic extractors can be easily combined with counter-current flow extraction towers, which are mainly used for sugar beet extraction. A short sonication of the sugar beet cossettes before they enter the counter-current extraction system help to disrupt and open the cell walls. Ultrasonication promotes mass transfer between the solvent (i.e., water) and beet cossettes, so that the intracellular molecules such as sucrose are transferred from the cell interior to the solvent. The ultrasonic pre-treatment of sugar beet cossettes facilitates and accelerates the sucrose extraction in the counter-current flow column.
Comparison of Ultrasonic vs Counter-Current Extraction
Fu et al. (2013) compared the traditional counter-current flow extraction with ultrasonic extraction of sucrose from sugar beet cossette. The results of the study showed that sonication resulted in higher yield of superior purity, whilst the extraction time was significantly reduced from 70 min. (countercurrent) to 40 min. (sonication). Ultrasonically assisted extraction (UAE) results in a lower colloidal impurity concentration (especially pectins), and gives a higher sucrose yield (94.0±0.15%). The extracted juice of high purity (92.6±0.11%). (cf. Fu et al., 2013)
Since sugar production facilities are already equipped with conventional countercurrent extraction towers, the combination of synergistic sonication with the existing installation is generally favoured. In order to apply ultrasonic sucrose extraction in the most cost- and time-efficient manner, ultrasonic extraction can be installed as synergistic treatment before, during, or after conventional counter-current flow extraction. As sonication disrupts the sugar beet cells and releases the sucrose from the cells, the duration of the counter-current flow treatment can be reduced, whilst the sucrose yield is enhanced.
- Accelerated process
- Higher yields
- Process intensification
- Synergetic effects w/ countercurrent systems
- Easy retro-fitting
- Simple testing
- Linear scalability
- Low maintenance
- Fast RoI
High Performance Ultrasonic Extractors
Hielscher Ultrasonics’ extraction systems are used worldwide in food and pharma for the commercial production of high quality extracts used as food products, dietary supplements or pharmaceuticals. Wether you want to test and optimise ultrasonic processing parameters on bench-top level or install a fully-industrial ultrasonic extraction system for inline production, Hielscher Ultrasonics has the suitable ultrasonic extraction setup for you. A small foot print and flexible installation options allow for retro-fitting even in a crammed processing facility.
Process Standardization with Hielscher Ultrasonics
Food-grade products should be produced in accordance to Good Manufacturing Practices (GMP) and under standardised processing specifications. Hielscher Ultrasonics’ digital extraction systems come with intelligent software, which makes it easy to set and control the sonication process precisely. Automatic data recording writes all ultrasonic process parameters such as ultrasound energy (total and net energy), amplitude, temperature, pressure (when temp and pressure sensors are mounted) with date and time stamp on the built-in SD-card. This allows you to revise each ultrasonically processed lot . At the same time, reproducibility and continuously high product quality are ensured.
Hielscher Ultrasonics’ industrial ultrasonic processors can deliver very high amplitudes. Amplitudes of up to 200µm can be easily continuously run in 24/7 operation. For even higher amplitudes, customized ultrasonic sonotrodes are available. The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation at heavy duty and in demanding environments.
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
- Fu et al. (2013): The ultrasonic-assisted extraction of sugar from sugar beet cossettes. International Sugar Journal, Sept. 2013. 696-700.
- Petigny L., Périno-Issartier S., Wajsman J., Chemat F. (2013): Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.). International journal of Molecular Science 14, 2013. 5750-5764.
- Martín-García Beatriz; Pasini, Federica; Verardo, Vito; Díaz-de-Cerio, Elixabet; Tylewicz, Urszula; Gómez-Caravaca, Ana María; Caboni Maria Fiorenza (2019): Optimization of Sonotrode Ultrasonic-Assisted Extraction of Proanthocyanidins from Brewers’ Spent Grains. Antioxidants 2019, 8, 282.
Facts Worth Knowing
Sucrose, also known as table sugar, is mainly produced from sugar cane and from sugar beets (Beta vulgaris). Sugar, i.e., sucrose, is extracted from beets using hot water in a multi-step step process, where raw sugar juice is extracted in a hot water diffusion in a countercurrent flow system. Afterwards, the sugar juice is concentrated under vacuum, followed by cyclic washing and finally drying.
After harvest, the beet roots are transported to the sugar processing plant, where the beets are washed and then mechanically cut into thinly sliced strips, the so-called cossettes. The cossettes are fed into to counter-current flow extraction system. The countercurrent system works by diffusion and leaches the sugar content from the cossettes into hot water.
The countercurrent diffusion systems are long reactors or high towers / columns of several metres in which the cossettes flow in one direction (upwards) while hot water flows in the opposite direction (downstream). Modern tower extraction plants have a processing capacity of up to 17,000 metric tons per day. The typical retention time of cossettes in the countercurrent tower is approx. 90 min., whilst the water remains only 45 min. in the diffuser column. The main advantage of counter-current flow systems is the reduced water use when compared to sugar beet maceration in a hot water reactor. The sugar juice solution which is produced in the counter-current diffusion system is called raw juice. The raw juice colour can vary between black to dark red depending on its oxidation level.
The spent cossettes exits the diffusion system as pulp with approx. 95% moisture, but low sucrose content.
The moist pulp is pressed with a screw press to approx. 75% moisture to recover remaining sucrose from the pulp.
The remaining pulp is dried and used mainly as animal feed.
Carbonatation is applied to remove impurities from raw juice before it can be precipitated to sugar crystals. Therefore, the raw juice is mixed with hot milk of lime, i.e., a suspension of calcium hydroxide in water. During the carbonatation, impurities such as sulfates, phosphates, citrate and oxalates precipitate. They precipitate in form of calcium salts and larger organic molecules , e.g. proteins, pectins, and saponins. Additionally, the alkaline pH value converts the simple sugars glucose and fructose along with the amino acid glutamine, to chemically stable carboxylic acids, which can be removed later via filtration, since those molecules would interfere with the crystallization.
In the following process step, carbon dioxide is bubbled through the alkaline sugar solution, precipitating the lime as calcium carbonate. The calcium carbonate particles bind some impurities. The heavy particles settle in the tank and can be removed via filtration.After these purification and cleaning steps the so-called thin juice is obtained. The thin juice might be treated with soda ash to adjust the pH value as well as with a sulfur-based compound to reduce colouring, which might occur due to thermal decomposition of monosaccharides.
Evaporation is used to concentrate the thin juice using multiple-effect evaporation systems, so that the thin juice turns into a thick juice. The thick juice has approx. 60% sucrose by weight.
In the final step, the thick juice is treated in crystallizers. By adding and dissolving recycled sugar, a so-called mother liquor is produced. The mother liquor is concentrated further by boiling under a vacuum in large vessels, known as vacuum pans, and very fine sugar crystal are added as seeding points. These crystals grow as sugar from the mother liquor forms around them. The resulting sugar crystal / syrup mixture is called a massecuite, a French term wich means “cooked mass”. The massecuite is fed into a centrifuge, where the “High Green syrup” is removed from the massecuite by centrifugal force. After a centrifucagtion, water is then sprayed into the centrifuge to wash the sugar crystals, which produces a so-called “Low Green syrup”. The centrifuge then spins at very high speeds to partially dry the crystals. When the centrifuge slows down, the sugar is scraped from centrifuge walls onto a conveyer system to transport the sugar into a rotation granulator where it is dried by warm air. The dry, clean sugar crystals are ready to be sold to refineries or food manufacturers for further treatment or use.