Soy Protein Ingredients

High molecular weight proteins (>50,000 g/mole) are needed to form texture during extrusion of soy protein ingredients. 

Genovese MI, Barbosa AC, Pinto Mda S, Lajolo FM. 2007. Commercial soy protein ingredients as isoflavone sources for functional foods. Plant Foods Hum Nutr 62 53-58. 

Soy protein ingredients used in adhesives are typically modified using high sodium hydroxide concentrations and pressure. AMSP adhesive is stronger and more water-resistant compared with adhesives containing unmodified soy protein (Hettiarachchy et al., 1995). 

Other soy protein products include dried soy milk and tofu (see the Chapter Food Use of Whole Soybeans), as well as mixtures of SF, SPC, or SPI with milk or egg protein, gelatin, or other components for specific functional applications. Extruder-texturized fburs and concentrates and spun fiber isolates, which resemble meat in appearance, may be made at the point of use but usually are supplied in bulk from strategically located production facilities. Edible co-products of soy protein ingredient manufacture include the hulls and the cotyledon fiber (cell walls) from SPI or soymilk production. The extract by-product from SPC may be used as the feedstock for isolating isoflavones. 

The vast majority, but not all, of the nitrogen in soy protein ingredients is of protein origin. The AOCS conversion factor for soybean protein is N x 5.71 however, industry practice is to label protein content as Protein (N x 6.25). Nitrogen may be deter-... 

FFSFs and grits are the least refined soy protein ingredients. Three types of FFSFs are produced (i) enzyme-active, (ii) toasted, and (iii) extruder-processed. Re-fatted flours are sometimes referred to as fully-fatted or full-fat, but they are described in this chapter in the section on defatted SF because the original fat is removed and replaced with refined, bleached, and deodorized (RED) oil. 

Generally, one can predict about a soy protein s functional performance by examining chemical compositions in manufacturers product specification sheets. Matrix tables, showing potential applications of a manufacturer s product line, also teach little. But for general guidance tables, such as Table 19.10, provide guidance about what types of soy protein ingredients should be considered for specific applications. 

Table 19.9. Functional Properties Performed by Soy Protein Ingredients in Foods ...

Table 19.12. Baking Applications for Various Soy Protein Ingredients ...

Deak, N.A. L.A. Johnson. Functional properties of soy protein ingredients prepared from high-sucrose/low-stachyose soybeans./. Am. Oil Chem. Soc. 2006, 83, 811-818. 

Lawhon, J.T. K.C. Rhee E.W. Lusas. Soy protein ingredients prepared by new processes—aqueous processing and industrial membrane isolation./. Am. Oil Chem. Soc. 1981,58, 377-384. 

Surface-active proteins can be extracted from a variety of plant sources, including legumes and cereals [60]. A considerable amount of research has been carried out to establish the ability of these proteins to stabilize emulsions, and whether they could be made into commercially viable value-added ingredients for utilization as emulsifiers in foods [90, 91]. One of the most widely studied proteins extracted from a plant source is soy protein, which is commercially available as a protein concentrate or isolate [92-95]. Soy protein ingredients are a complex mixture of many individual protein fractions with different molecular and functional characteristics (e.g. 2S, 7S, US, and 15S fractions) [60]. In addition, each of these fractions contains a mixture of different protein sub-units that also have different molecular and functional characteristics. 

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