The nutritional value of soyfood products varies considerably. As a general rule, they are lower in fat, but there are exceptions. Meat alternatives made from soybeans serve as excellent sources of protein, iron and B vitamins. Boasting 10g of protein, the grilled chicken and sausage gumbo variety of Campbell Soup's (Camden, N.J.) Chunky soup lists soy protein isolate (SPI) among its ingredients. The most highly refined soy protein, SPI is the result of isolating soy protein from defatted soy flakes. Containing at least 90% protein, SPIs have the greatest amount of protein content of all soy ingredients. Furthermore, they serve as a highly digestible source of amino acids, regarded as the protein building blocks needed for proper human growth and maintenance.
Compatible with traditional batch pressure-cook processes for cereal, many textured soy protein concentrates can be added into a mixture of split or crushed grains cooked together. A low-pressure extruder then can be used to form the resulting dough into pellets, which are rolled into flakes.