Soy proteins are (by volume) the most important vegetable protein in the
world market. The soya beans are typically grown in The United States, Latin
America, China and Africa.
Soya beans are composed of:
- Protein: 40% (of which about 80% is water soluble).
- Oil: 20%
- Fibers: 10%
- Carbohydrates and salts: 20%
- Water: 10%
This composition is only approximate as it depends on the type of bean,
weather, soil and other growing conditions.
What can GEA Niro
do for you?
The GEA Group is engaged and recognized as an
important partner world-wide for designing and supplying complete process lines
for Soy Protein Isolate (SPI) and the valuable by-products from the process
such as fibers/insoluble proteins, carbohydrates and salts.
Nozzle tower
The feed
material for production of SPI is defatted soy flakes. Water is used for the
soaking of the soy flakes and the extraction of the water soluble soy protein.
Acid is used to precipitate the protein solution at the iso-electric point. The
protein curd is then separated and washed with water in decanters and
re-solubilized by neutralization. The protein content in the product is now 90%
or more (based on solids). The by-product from the extraction contains fibers
and the remaining un-dissolved proteins. Depending on the final use of the SPI
- be it in fortified energy drinks, as meat replacer or in powdered
infant formula/baby food - the
protein solution can be pasteurized or UHT treated before further processing.
Spray drying Soy Protein Isolate (SPI) is
spray dried in a
NOZZLE TOWER™ using
atomization by high pressure nozzles and a high drying air temperature. The
high protein content in the concentrate makes it very viscous. Low total solids
content is then necessary in the feed and the resulting powder will consist of
fine particles. To avoid powder loss, the process air is passed through bag
filters. By selecting a
Fluidized
Spray Dryer FSD™ , it will be possible to produce an agglomerated
free-flowing powder.
Processing of the by-products
The water used for soaking and extracting the soy flakes contains
carbohydrates and salts. The water is removed by evaporation and after
condensation polished in a
reverse
osmosis plant. The water can now be used for cleaning purposes or returned
to the extraction process thereby saving water.
The concentrate with
the carbohydrates and salts are mixed with the fiber/un-dissolved protein
fraction from the extraction. This mixture is then dried in a
Ring Dryer and used for
animal feed.
Final result
The two powder products:
the SPI and the by-products, can be
conveyed to silos and
bagged off in suitable bags. Thus, the GEA Niro process leaves
no product loss and the water used in the process is reused for cleaning.