Soy protein concentrate is a processed soy ingredient containing a minimum of 65% protein on a dry-weight basis. It sits between basic soy flour (around 50% protein) and soy protein isolate (90%+ protein) in terms of purity, and it’s one of the most widely used plant proteins in the food industry. You’ll find it in everything from meat alternatives and protein bars to animal feed and infant formulas.
How It’s Made
The process starts with defatted soy flakes, which are what’s left after soybeans are crushed and their oil is extracted. These flakes contain protein, but also about 8% free sugars and other soluble compounds that dilute the protein content. The goal is to wash away those sugars and low-molecular-weight components while keeping the protein intact.
There are three main ways to do this:
- Aqueous alcohol wash: The most common commercial method. Defatted flakes are mixed with a roughly 60% ethanol solution, which dissolves sugars but doesn’t dissolve soy proteins. After extraction, the alcohol is evaporated, recovered, and recycled. The remaining solids are dried and ground into powder.
- Acid wash: The flakes are mixed with water adjusted to a pH of about 4.5, which is the point where soy proteins are least soluble. The sugars dissolve into the water while the proteins stay in the solid phase. The solids are separated by centrifuge, and the resulting concentrate can be neutralized to a more functional pH before drying.
- Heat denaturation and water wash: The proteins are first made insoluble through moist heat treatment. Then hot water extracts the sugars from the heat-treated meal. This is the simplest approach but produces a concentrate with less functional versatility.
The choice of method matters beyond just protein yield. Alcohol washing, for instance, strips out most isoflavones (the antioxidant compounds naturally present in soy) along with the sugars. Heat-based processing can reduce the protein’s ability to bind water or form gels, which limits its usefulness in certain food applications.
Nutritional Profile
The defining feature of soy protein concentrate is its minimum 65% protein content on a moisture-free basis, though many commercial products test higher. The remaining composition includes dietary fiber, a small amount of fat, minerals, and residual carbohydrates. Oligosaccharides (the short-chain sugars that cause gas in some people) are reduced to less than 3.5%, which is a significant drop from whole soybeans.
Protein quality is high. When measured using the PDCAAS method, which scores a protein’s ability to deliver essential amino acids based on both its amino acid profile and digestibility, soy protein concentrate scores between 0.95 and 1.00. A score of 1.00 is the maximum, putting it on par with animal proteins like eggs and milk. The slight variation in published scores comes down to differences in testing labs and processing methods rather than any fundamental gap in quality.
Soy protein provides all nine essential amino acids, which makes it one of the few plant proteins considered “complete.” Its limiting amino acid is methionine, but at levels that still meet human nutritional requirements for most age groups.
Concentrate vs. Isolate
Soy protein isolate goes a step further than concentrate by removing not just the soluble sugars but also the insoluble fiber and polysaccharides. The result is a product with 90% or more protein, a more neutral flavor, and better solubility in liquids. These properties make isolate the preferred choice for protein shakes, smoothie powders, and applications where a clean taste matters.
Concentrate retains more of the original soybean’s fiber and has a slightly beany flavor that works well in products where it isn’t the star ingredient: processed meats, baked goods, cereals, and textured vegetable protein. It’s also meaningfully cheaper to produce than isolate because the processing is less intensive. For food manufacturers, concentrate often hits the sweet spot between protein content and cost.
How the Food Industry Uses It
Soy protein concentrate is valued less for its protein content alone and more for what it does in a formulation. It binds water, which helps processed meats retain moisture during cooking. It emulsifies fat, keeping oil and water from separating in sauces and dressings. And it improves texture in baked goods, giving structure without gluten.
In meat alternatives, soy protein concentrate is often extruded under heat and pressure to create a chewy, fibrous texture that mimics muscle. This “textured soy protein concentrate” is the base of many plant-based burgers, sausages, and chicken substitutes. In conventional meat products like sausages and deli meats, it serves as a binder and extender, reducing cost while improving juiciness.
Animal feed is another major market. In aquaculture and pig farming, soy protein concentrate replaces fishmeal and other expensive protein sources. The removal of oligosaccharides and antinutritional factors during processing makes it easier for young animals to digest compared to raw soybean meal.
Antinutrients and Processing
Raw soybeans contain trypsin inhibitors, compounds that interfere with protein digestion. Processing reduces these significantly but doesn’t eliminate them entirely. Soy protein concentrates retain intermediate levels of trypsin inhibitors, lower than raw soy but somewhat higher than soy protein isolates. In finished food products like infant formulas, residual trypsin inhibitor content drops to 3 to 28% of the levels found in raw soybeans, depending on the specific processing conditions used.
Phytates, which can reduce mineral absorption, are also partially removed during the washing steps. The acid wash process tends to be more effective at reducing phytates than alcohol washing because phytic acid is more soluble at low pH. For most people eating a varied diet, the remaining levels are not a practical concern, but it’s one reason soy protein concentrate is sometimes further processed for sensitive applications like infant nutrition.
Environmental Footprint
Plant-based proteins carry a substantially smaller environmental burden than animal-based alternatives, and soy protein is no exception. Lifecycle analysis of soy protein isolate (the closest product with published data) found a carbon footprint of 2.4 kg CO2 equivalents per kilogram of protein. For comparison, whey protein concentrate comes in at 16, chicken at 17, and pork at 24. Soy protein concentrate would fall in a similar range to isolate, potentially slightly lower given its less intensive processing.
Land use follows the same pattern. Soy protein requires less than half the land needed to produce the same amount of whey protein, and a fraction of what’s needed for beef. Water use for soy and whey protein is comparable, but both are markedly lower than pork or beef production. Replacing even half of the whey protein concentrate used in sports nutrition beverages globally with soy protein could avoid an estimated 424,000 tons of CO2 emissions annually.
Market Size and Growth
The global soy protein market is projected to reach $8.6 billion in 2026, growing to $10.89 billion by 2031 at a rate of about 4.8% per year. North America is the largest market, accounting for roughly a third of global demand, supported by its large-scale soybean crushing infrastructure. The Asia-Pacific region is growing fastest, driven by protein fortification programs in China and India, with a projected growth rate of 5.4% annually through 2031.