Soy meal is a grainy, flour-like substance made from the leftover fragments of soybeans that have already been processed for oil. The extraction of oil from soybeans, whether by chemical solvents or machine efforts, leaves behind mush, which manufacturers typical call bean chips, bean flakes and bean cakes. These remnants are then ground into a powder that is valued by some for its high non-animal protein content.
Soy meal is often used to feed livestock and farmed fish, but has worked its way into human diets as well. First introduced in China in the 11th century, soy contains high amounts of amino acids, which promote greater energy levels and muscle development. Heat and solvents like hexane are used to dry out bean mush to make soy meal, which typically consists of 44 to 80 percent protein and less than 1 percent fat. It has traces of phosphorus, little fiber and no carbohydrates. The primary amino acids in soybean meal include tryptophan, lysine, and threronine—all nine amino acids, however, are found in significant quantities in the soybean meal, making it a complete protein.
Traditionally, soy meal has primarily been used by farmers to feed chickens and cattle. The rise of the protein bar industry, however, combined with the abundance of soybean crops has created an escalating interest in using soy meal in health-conscious convenience food. Powdered protein shakes, cereals, and packaged protein bars often have soy meal as an ingredient. Many baby food products also contain soybean meal.
Packages of soy meal can be bought in many health food stores and grocery marts to make baked goods at home. The meal is often substituted for flour in bread recipes to reduce carbohydrates and boost protein content. Muffins, tortillas, and cookies are among the most popular homemade goods using soybean meal.
The use of soy for humans has raised occasional concern among some doctors. While some nutritionists promote soy for humans, claiming it can help prevent heart disease and prostate cancer, others caution that the processing of soy can introduce too much toxic hexane into human diets. Detractors also often express concern that excess soy exposes consumers to too many phytoestrogens. Soy contains daidzein and genistein, which mimic the female hormone estrogen and, according to some doctors, can create hormonal imbalances at high doses, particularly in men. Vegetarian proponents of soy, however, hail it as an inexpensive and beneficial replacement for beef, pork, and chicken.
Beyond food, soy meal has also been used in the manufacturing industry. It is often blended with rubber, polymers, and plastics to create rubber bands, film, and tubing. The inclusion of soybean meal in rubber and plastic products makes the end product more water-resistant and elastic.