Soy Protein Concentrate is one of many products obtained during the processing of mature soybeans. High quality soybeans are
selected and cleaned as the first step in soy product processing.The clean soybeans are dehulled, then the oil is extracted for cooking, biodiesel and other uses. The residue, consisting of defatted white flakes, can then be ground to make soy flour, toasted and ground to make soybean meal, or subjected to further processing to produce value-added soy fiber and protein concentrate and isolate products.
SPC is made by treating the white soy flakes to aqueous alcohol extraction as shown in the processing flow chart in Figure 1. This extraction process removes the soluble carbohydrate and significantly lowers the levels of lectins, trypsin inhibitors, glycinin, B-conglycinin, saponins and oligosaccharides that are considered to be anti-nutritional factors (ANF’s) in regular soybean meal.
These ANF’s have been documented to cause gastrointestinal disturbances, intestinal damage, increased disease susceptibility and reduced performance in some aquatic species.
The resulting traditional soy protein concentrate is then thermally processed to further reduce ANF’s and produce low-antigen, feedgrade SPC. Low-antigen SPC has nutritional qualities that make it ideal for use in nutrient dense aquafeeds for marine fish species, marine shrimp and for fry and fingerling feeds of both freshwater and marine fish. Research has also identified higher energy and nitrogen digestibility for SPC over soybean meal included in feed for fish.
Soybean protein isolates are full-value protein food additives having protein content of more than 90% and are used mainly in food products. About twenty different amino acids are present in soybean protein isolates including all the essential amino acids. It can replace animal protein. Soybean protein isolates can be used in meat products, minced meat ham sausages, emulsified sausages, surimi and other sea foods, quick-frozen prepared products and tumbled products. Soybean proteins are also used in salad dressings, soups, meat analogues, beverage powders, cheeses, non-dairy creamers, frozen desserts, whipped toppings, infant formulae, bread, breakfast cereals, and pastas. Functionally, soybean protein isolates are mainly used to improve the texture of meat products, but are also added to increase protein content, to enhance moisture retention, and as an emulsifier.
Pure soybean protein isolates are also available in pharmacies as a part of nutritional formulations along with other food ingredients.
Soybean protein concentrates are widely used as functional or nutritional ingredients in a wide range of food products, mainly in bakery products, breakfast cereals, and in some meat products. They are used in meat and poultry products to increase water and fat (oil) retention and to improve nutritional values, i.e., to increase the protein content and reduce the fat. Soybean protein concentrates are very digestible and therefore are well-suited for children, pregnant and lactating women and the elderly people. They are also used in milk replacements, pet foods, as well as in some non-food applications.