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Alfa Laval Foodec decanter centrifuges for processing soy protein isolate

Soy protein isolate – the growing alternativeSoy protein isolate is the most concentrated form oflow-fat, high-protein nutrition currently available, andis in great demand.

The most hygienic and efficient way to process soyprotein isolate is with Foodec decanter centrifugesfrom Alfa Laval.

Alfa Laval in briefAlfa Laval is a leading global provider ofspecialized products and engineeredsolutions. Our equipment, systems and services are dedicated to helpingcustomers to optimize the performanceof their processes. Time and time again.

We help our customers to heat, cool, separate and transport productssuch as oil, water, chemicals,beverages, foodstuffs, starch andpharmaceuticals.

Our worldwide organization worksclosely with customers in almost 100countries to help them stay ahead.

How to contact Alfa LavalUp-to-date Alfa Laval contact details forall countries are always available on ourwebsite at www.alfalaval.com

2 Alfa Laval Foodec decanter centrifuges

Unlike most other beans, soybeansprovide a “complete” protein profile.Soybeans contain all the essentialamino acids that we need from our diet,because our bodies are simply notcapable of synthesizing them.

This means that soy protein productsare excellent substitutes for animalproducts and animal-based foods.These, too, are a good source ofcomplete proteins, but they have thedisadvantage of containing more fats,especially those of the saturated kind.

Soy protein is now one of the majorsources of protein for both livestockand human consumption. With aprotein content of 90% (based on dryweight), soy protein isolate (SPI) is themost concentrated form of soy proteinavailable.

Improving, updating and expandingBecause soy protein isolate has such ahighly desirable protein profile, theworld market for this product is growingextremely rapidly – in some regions byas much as 30–40% each year.

This means that manufacturers have asubstantial need to● replace older, less efficient and less

hygienic equipment with a new generation of high-quality units that eliminate production bottlenecks and optimize the overall processing flow

● install new high-efficiency processing equipment that ensures a boost in capacity, maximum flexibility and tip-top levels of hygiene. The Foodec benefits for SPI

include● up to 25% greater solids handling

capacity, at no extra cost● unparalleled hygiene standards,

which mean better product value● reduced power consumption,

which means lower operating costs● better control, which means greater

process efficiency and increased profits. Foodec decanter

centrifugeFoodec decanter

centrifuge

Foodec decantercentrifuge

Foodec decantercentrifuge

Disc stack centrifuge

Batch mixer tank

Defattedsoy

Pre-conditioning agent

Centrate

Feed

Wet cake

Mixer tank

Solid waste for animal feed

Protein isolatefor further processingWastewater for

further treatment

y p

Disc stack centrifuge

Mixer tank

Mixer tank

This is achieved by re-suspending thecurd in water and then using adecanter centrifuge to separate thetwo components. Recovery can thenbe improved still further using an Alfa Laval disc stack centrifuge. Thewashed “isoelectric soy protein isolate”can then be spray-dried, or neutralizedand then spray-dried to form so-calledproteinates.

Benefit from Foodec decantercentrifuges in your SPI processingThe unique design of the Alfa LavalFoodec range features a series of built-in advantages that provide you withsubstantial processing benefits. Theseinclude● better solids transportation that

enables you to boost solids handling capacity by up to 25% compared with all other designs currently available – at no additional cost

● special sanitary design that enables you to match stringent FDA, 3A and USDA standards. The Foodec designalso focuses on ease of cleaning

● an advanced drive system that enables you to operate at any given capacity with significantly lower power consumption than other current designs

● a new drive and control system that reduces your operating costs and gives you even better control over the separation process. This makes itpossible to reduce production costs as well as boosting the quality and value of the end product.

Alfa Laval Foodec decanter centrifuges 5

The processThe principles used in the productionof soy protein isolate are basicallysimple. Using defatted soy flour orflakes as the starting material, theprotein is first dissolved in water. Theresulting solution is then separatedfrom the solid residue. Finally, theprotein is precipitated from thesolution, and then separated and dried.

The objectivesFor companies in the soy proteinindustry, the prime objectives are toimprove both product purity and yield.These depend on many differentparameters, including alkalinity,extraction time, temperature, the ratioof water to soy meal, heat treatmentand agitation.

Alfa Laval and soy processingOne of the key features of the soyprotein isolate production process isthe separation of the protein from thesolid soybean residue. The Alfa LavalFoodec range of decanter centrifugesis particularly well suited for dealingwith this. Foodec decanter centrifugesare specially designed to meet thehygiene requirements of soy proteinmanufacturers and other quality-conscious food industry companies.

Protein extractionThe soy meal is mixed with water andisoelectrically adjusted so that themajority of the protein goes intosolution. This protein-rich solution mustthen be separated from the solidmatter (known as okara). A traditionalconfiguration for doing this featuresextraction consisting of vibrating androtary screens, followed by optionalpurification and concentration.

However, Alfa Laval Foodec decantercentrifuges are ideal as a replacementfor such traditional systems, becauseof their extreme efficiency and highsolids handling capacity.

Protein precipitationThe protein solution is nowisoelectrically adjusted still further sothat the protein can be precipitated.The solidified protein (known as curd)must then be separated out.

Alfa Laval Foodec decanter centrifugesare widely considered the preferredchoice for this process. This is due totheir exceptional solids handlingcapacity, high standards of hygieneand low cleaning and maintenancerequirements.

Curd washingThe precipitated protein (curd) isseparated from the supernatant (whey)using a decanter centrifuge. This curdmust then be washed in order toremove any whey residues. Thoroughwashing is an important step inobtaining soy protein isolate of high purity.

High-efficiency process flow chart – soy protein isolate

Soybeans – a long time under wayAfter extensive studies, the US Foodand Drug Administration (FDA)authorized the use of the followinghealth statement on soy proteinproducts in 1999: “Diets low insaturated fat and cholesterol thatinclude 25 grams of soy protein a daymay reduce the risk of heart disease.”

Complete protein profile