Pilot plant for aqueous extraction

For recovering protein products

Pilot plant for aqueous extraction
The aqueous extraction allows protein isolates and concentrates to be obtained from oil-free flour or flakes

The Fraunhofer IVV possesses a batch pilot plant for manufacturing protein isolates and concentrates from oil-free meal or flakes. Per batch 50-200kg of raw material can be processed. The recovery of protein is generally carried out by aqueous extraction followed by downstream fiber separation via a decanter. The recovered protein solution is then concentrated by either isoelectric precipitation with downstream separation or by ultrafiltration. The protein quark or protein enriched retentate is usually dried and stabilized in a spray tower.  
The modular design means that individual process steps can be used separately in order to gain insight into specific aspects of protein recovery.
During the process, all relevant process parameters from each processing step are stored in a data protocol. The evaluation of a particular recovery process is performed by balancing the process steps and measurement of the protein yield. The characterization of the protein products can be carried out in our laboratories.
If desired, seed preparation (dehulling, classification, and flaking) before the protein recovery or the deoiling of the starting material can be performed in our pilot plant.


Features of the pilot plant units

Three stirred 2m3 vessels are available for protein extraction and precipitation. All these vessels have temperature and pH control as well as filling level control. The amount of solid can be up to 20% of the working volume.

A two-phase decanter is available for separating the fiber-containing raffinate: drum diameter: 300mm, equivalent clarifying area: 2213m2, reference capacity: max. 15m3/h with free solids discharge.
To separate the proteins after precipitation there is a clarifying separator: Total volume: 8l, volume of the solid: 4l, reference capacity: 11m3/h, intermittent solids discharge.

Ultrafiltration uses modules with capillary membranes made of polysulfone. The separation area is a maximum of 9m2. The concentrating of the proteins is at a cut-off of either 6 or 10kDa depending on requirements. The filtration throughput is 100-1500-/h depending on the product properties and the plant can withstand a maximum differential pressure of 5 bar. The filtration processes can be carried out at temperatures of 22-70°C and at pH values of 2-10. The computer controlled plant independently regulates the ultrafiltration pressure, backwash, temperature, and addition of diafiltration medium.

Spray dryer
For temperature-sensitive products the universal spray dryer is operated with single batches and an internal mixing two-substance nozzle. The evaporation rate is in the range from 25-40kg/h depending on the inlet temperature (180-250°C) and outlet temperature (60-100°C). It is also possible to use a centrifugal atomizer instead of a nozzle and to agglomerate the end product. This involves an internal and external fluidized bed with fines return.