and
soy sauce, both made from soy beans Among the
legumes, the soybean is valued for its high (38–45%)
protein content as well as its high (approximately 20%) oil content. Soybeans are the most valuable agricultural export of the United States. Approximately 85% of the world's soybean crop is processed into soybean meal and soybean oil, the remainder processed in other ways or eaten whole. Soybeans can be broadly classified as "vegetable" (garden) or field (oil) types. Vegetable types cook more easily, have a mild, nutty flavor, and better texture, are larger in size, higher in protein, and are lower in oil than field types.
Tofu,
soy milk, and
soy sauce are among the top edible commodities made using soybeans. Producers prefer the higher protein cultivars bred from vegetable soybeans originally brought to the United States in the late 1930s. The "garden" cultivars are generally not suitable for mechanical combine harvesting because there is a tendency for the pods to shatter upon reaching maturity.
Nutrition A 100-gram reference quantity of raw soybeans supplies of
food energy and are 9% water, 30%
carbohydrates, 20% total
fat and 36%
protein.
Peanuts are the only
legumes with a higher fat content (48%) and calorie count (2,385 kJ). They contain less carbohydrates (21%), protein (25%) and dietary fiber (9%). Soybeans are a rich source of
essential nutrients, providing in a 100-gram serving (raw, for reference) high contents of the
Daily Value (DV) especially for protein (36% DV),
dietary fiber (37%),
iron (121%),
manganese (120%),
phosphorus (101%) and several
B vitamins, including
folate (94%) (table). High contents also exist for
vitamin K,
magnesium,
zinc and
potassium. For human consumption, soybeans must be processed prior to consumption–either by cooking, roasting, or fermenting–to destroy the
trypsin inhibitors (
serine protease inhibitors). Raw soybeans, including the immature green form, are toxic to all
monogastric animals.
Protein Most soy protein is a relatively heat-stable storage protein. This heat stability enables soy food products requiring high temperature cooking, such as
tofu,
soy milk and
textured vegetable protein (soy flour) to be made.
Soy protein is essentially identical to the protein of other
legume seeds and
pulses. Soy is a good source of protein for vegetarians and
vegans or for people who want to reduce the amount of meat they eat, according to the
US Food and Drug Administration: Although soybeans have high protein content, soybeans also contain high levels of
protease inhibitors, which can prevent digestion. Protease inhibitors are reduced by cooking soybeans, and are present in low levels in soy products such as
tofu and
soy milk. All
spermatophytes, except for the family of grasses and cereals (
Poaceae), contain 7S (
vicilin) and 11S (
legumin) soy protein-like globulin storage proteins; or only one of these
globulin proteins. S denotes
Svedberg, sedimentation coefficients. Oats and rice are anomalous in that they also contain a majority of soybean-like protein. Cocoa, for example, contains the 7S globulin, which contributes to cocoa/chocolate taste and aroma, whereas coffee beans (coffee grounds) contain the 11S globulin responsible for coffee's aroma and flavor. Vicilin and legumin proteins belong to the
cupin superfamily, a large family of functionally diverse proteins that have a common origin and whose evolution can be followed from bacteria to eukaryotes including animals and higher plants. 2S
albumins form a major group of homologous storage proteins in many
dicot species and in some
monocots but not in grasses (cereals). Soybeans contain a small but significant 2S storage protein. 2S albumin are grouped in the
prolamin superfamily. Other allergenic proteins included in this 'superfamily' are the non-specific
plant lipid transfer proteins,
alpha amylase inhibitor,
trypsin inhibitors, and prolamin storage proteins of cereals and grasses.
Other constituents Soy contains
isoflavones—
polyphenolic compounds, produced by legumes including peanuts and
chickpeas. Isoflavones are closely related to
flavonoids found in other plants, vegetables and flowers.
Saponins, a class of natural
surfactants (soaps), are sterols that are present in small amounts in various
plant foods, including soybeans, other
legumes, and cereals, such as oats.
Comparison to other major staple foods The following table shows the nutrient content of green soybean and other major staple foods, each in respective raw form on a
dry weight basis to account for their different water contents. Raw soybeans, however, are not edible and cannot be digested. These must be sprouted, or prepared and cooked for human consumption. In sprouted and cooked form, the relative nutritional and anti-nutritional contents of each of these grains is remarkably different from that of raw form of these grains reported in this table. The nutritional value of soybean and each cooked staple depends on the processing and the method of cooking: boiling, frying, roasting, baking, etc.
Soybean oil Soybean seed contains 18–19% oil. The oil is then refined, blended for different applications, and sometimes hydrogenated. Soybean oils, both liquid and partially hydrogenated, are exported abroad, sold as "vegetable oil," or end up in a wide variety of processed foods. In 2022 China was the main producer of soybean oil, with a share of 29%, and the United States of America in second with a share of 21%.
Soybean meal Soybean meal, or soymeal, is the material remaining after solvent extraction of oil from soybean flakes, with a 50%
soy protein content. The meal is 'toasted' (a
misnomer because the heat treatment is with moist steam) and ground in a
hammer mill. Ninety-seven percent of soybean meal production globally is used as livestock feed. Soybean meal is also used in some
dog foods.
Livestock feed One of the major uses of soybeans globally is as livestock feed, predominantly in the form of soybean meal. In the European Union, for example, though it does not make up most of the weight of livestock
feed, soybean meal provides around 60% of the protein fed to livestock. In the United States, 70 percent of soybean production is used for animal feed, with poultry being the number one livestock sector of soybean consumption. The
American Soybean Association estimates that over 90% of U.S. soybeans are used as animal feed and 97% of soybean meal feeds livestock and poultry.
Spring grasses are rich in omega-3 fatty acids, whereas soy is predominantly omega-6. The soybean hulls, which mainly consist of the outer coats of the beans removed before oil extraction, can also be fed to livestock and whole soybean seeds after processing.
Food for human consumption ) using Soya beans In addition to their use in livestock feed, soybean products are widely used for human consumption. Common soybean products include
soy sauce,
soy milk,
tofu,
soy meal,
soy flour,
textured vegetable protein (TVP),
soy curls,
tempeh, soy
lecithin and
soybean oil. Soybeans may also be eaten with minimal processing, for example, in the Japanese food , in which immature soybeans are boiled whole in their pods and served with
salt. in
China –
Nepali fried soybeans In China, Japan, Vietnam and
Korea, soybean and soybean products are a standard part of the diet.
Tofu (豆腐
dòufu) is thought to have originated in China, along with
soy sauce and several varieties of
soybean paste used as seasonings. Japanese foods made from soya include
miso (),
nattō (),
kinako () and
edamame (), as well as products made with tofu such as
atsuage and
aburaage. In China, whole dried soybeans are sold in supermarkets and used to cook various dishes, usually after rehydration by soaking in water; they find their use in soup or as a savory dish. In
Korean cuisine, soybean sprouts (
kongnamul) are used in a variety of dishes, and soybeans are the base ingredient in
doenjang,
cheonggukjang and
ganjang. In Vietnam, soybeans are used to make soybean paste (
tương) in the North with the most popular products are
tương Bần,
tương Nam Đàn,
tương Cự Đà as a garnish for
phở and
gỏi cuốn dishes, as well as tofu ( or or ), soy sauce (), soy milk ( in the North or in the South), and (tofu sweet soup).
Flour Soy flour refers to soybeans ground finely enough to pass through a 100-mesh or smaller screen where special care was taken during desolventizing (not toasted) to minimize
denaturation of the protein to retain a high
protein dispersibility index, for uses such as
food extrusion of
textured vegetable protein. It is the starting material for soy concentrate and protein isolate production. Soy flour can also be made by roasting the soybean, removing the coat (hull), and grinding it into flour. Soy flour is manufactured with different fat levels. Alternatively, raw soy flour omits the roasting step. • Defatted soy flour is obtained from
solvent extracted flakes and contains less than 1% oil. • "Natural or full-fat soy flour is made from unextracted, dehulled beans and contains about 18% to 20% oil." Its high oil content requires the use of a specialized Alpine Fine Impact Mill to grind rather than the usual
hammer mill. Full-fat soy flour has a lower protein concentration than defatted flour. Extruded full-fat soy flour, ground in an Alpine mill, can replace/extend eggs in baking and cooking. Full-fat soy flour is a component of
Cornell bread. • Low-fat soy flour is made by adding some oil back into defatted soy flour. Fat levels range from 4.5% to 9%. • High-fat soy flour can also be produced by adding back soybean oil to defatted flour, usually at 15%.
Soy lecithin can be added (up to 15%) to soy flour to make lecithinated soy flour. It increases dispersibility and gives it emulsifying properties. Soy flour has 50% protein and 5% fiber. It has higher levels of protein, thiamine, riboflavin, phosphorus, calcium, and iron than
wheat flour. It does not contain
gluten. As a result,
yeast-raised
breads made with soy flour are dense in texture. Among many uses, soy flour thickens sauces, prevents
staling in baked food, and reduces oil absorption during frying. Baking food with soy flour gives it tenderness, moistness, a rich color, and a fine texture. Soy grits are similar to soy flour, except the soybeans have been toasted and cracked into coarse pieces.
Kinako is a soy flour used in
Japanese cuisine.
Soy-based infant formula Soy-based
infant formula (SBIF) is sometimes given to infants who are not being strictly breastfed; it can be useful for infants who are either allergic to pasteurized cow milk proteins or who are being fed a
vegan diet. It is sold in powdered, ready-to-feed, and concentrated liquid forms. Some reviews have expressed the opinion that more research is needed to determine what effect the phytoestrogens in soybeans may have on infants. Diverse studies have concluded there are no adverse effects in human growth, development, or reproduction as a result of the consumption of soy-based infant formula. One of these studies, published in the
Journal of Nutrition, Food service, retail and institutional (primarily school lunch and correctional) facilities regularly use such "extended" products. The extension may result in diminished flavor, but fat and cholesterol are reduced. Vitamin and mineral fortification can be used to make soy products nutritionally equivalent to animal protein; the protein quality is already roughly equivalent. The soy-based meat substitute
textured vegetable protein has been used for more than 50 years as a way of inexpensively extending
ground beef without reducing its nutritional value. In China and Taiwan, soy milk (known as
doujiang) is a traditional breakfast staple consumed for centuries. It is often perceived as a healthier, more natural alternative to cow's milk, which is a more recent addition to the local diet. Fresh soy milk is commonly distinguished from processed, packaged versions (
dounai).
Soy nut butter The soybean is used to make a product called soy
nut butter which is similar in texture to peanut butter.
Sweetened soybean Sweet-boiled beans are popular in Japan and Korea, and the sweet-boiled soybeans are called "Daizu no " in Japan and Kongjorim () in Korea. Sweet-boiled beans are even used in sweetened buns, especially in . The boiled and pasted edamame, called , is used as one of the
Sweet bean pastes in
Japanese confections.
Coffee substitute Roasted and ground soybeans can be a caffeine-free substitute for
coffee. After the soybeans are roasted and ground, they look similar to regular coffee beans or can be used as a powder similar to instant coffee, with the aroma and flavor of roasted soybeans.
Other products Soybeans with black hulls are used in Chinese fermented black beans,
douchi, not to be confused with
black turtle beans. Soybeans are also used in industrial products, including oils, soap, cosmetics,
resins, plastics, inks, crayons,
solvents, and clothing. Soybean oil is the primary source of
biodiesel in the United States, accounting for 80% of domestic biodiesel production. Soybeans have also been used since 2001 as fermenting stock in the manufacture of a brand of
vodka. In 1936, Ford Motor Company developed a method where soybeans and fibers were rolled together producing a soup which was then pressed into various parts for their cars, from the distributor cap to knobs on the dashboard. Ford also informed in public relation releases that in 1935 over five million acres (20,000 km) was dedicated to growing soybeans in the United States.
Potential health benefits Reducing risk of cancer According to the
American Cancer Society, "There is growing evidence that eating traditional soy foods such as tofu may lower the risk of cancers of the breast, prostate, or endometrium (lining of the uterus), and there is some evidence it may lower the risk of certain other cancers." There is insufficient research to indicate whether taking soy
dietary supplements (e.g., as a pill or capsule) has any effect on health or cancer risk. As of 2018, rigorous dietary
clinical research in people with cancer has proved inconclusive.
Gastrointestinal and colorectal cancer Reviews of preliminary clinical trials on people with
colorectal or
gastrointestinal cancer suggest that soy isoflavones may have a slight protective effect against such cancers.
Prostate cancer A 2016 review concluded that "current evidence from
observational studies and small clinical trials is not robust enough to understand whether soy protein or
isoflavone supplements may help prevent or inhibit the progression of
prostate cancer." Soy consumption has been shown to have no effect on the levels and quality of
sperm.
Meta-analyses on the association between soy consumption and prostate cancer risk in men concluded that dietary soy may lower the risk of prostate cancer.
Cardiovascular health The
Food and Drug Administration (FDA) granted the following health claim for soy: "25 grams of soy protein a day, as part of a diet low in
saturated fat and
cholesterol, may reduce the risk of
heart disease."
Research by constituent Lignans Plant
lignans are associated with high fiber foods such as cereal brans and beans are the principal precursor to mammalian lignans which have an ability to bind to human estrogen sites. Soybeans are a significant source of mammalian lignan precursor
secoisolariciresinol containing 13–273 μg/100 g dry weight.
Phytochemicals Soybeans and processed soy foods are among the richest foods in total
phytoestrogens (wet basis per 100 g), which are present primarily in the form of the
isoflavones,
daidzein and
genistein. Because most naturally occurring phytoestrogens act as
selective estrogen receptor modulators, or SERMs, which do not necessarily act as direct agonists of estrogen receptors, normal consumption of foods that contain these phytoestrogens should not provide sufficient amounts to elicit a physiological response in humans. The major product of daidzein microbial metabolism is
equol. Only 33% of Western Europeans have a
microbiome that produces equol, compared to 50–55% of Asians.
Phytic acid Soybeans contain
phytic acid, which may act as a
chelating agent and inhibit mineral absorption, especially for diets already low in minerals. ==In culture==