Fat-free (defatted) soybean meal is a significant and cheap source of protein for animal feeds and many prepackaged meals ; soy vegetable oil is another product of processing the soybean crop. For example, soybean products such as textured vegetable protein (TVP) are ingredients in many meat and dairy analogues. Soybeans produce significantly more protein per acre than most other uses of land.
Traditional nonfermented food uses of soybeans include soy milk, and from the latter tofu and tofu skin. Fermented foods include soy sauce, fermented bean paste, natto, and tempeh, among others. The oil is used in many industrial applications. The main producers of soy are the United States (35%), Brazil (27%), Argentina (19%), China (6%) and India (4%).
The beans contain significant amounts of phytic acid, alpha-linolenic acid,
and isoflavones. The plant is sometimes referred to as greater bean (大豆 – Chinese dàdòu and Japanese daizu ). Both the immature soybean and its dish are called edamame in Japan, but in English, edamame refers only to a specific dish. The genus name, Glycine, is the same as a simple amino acid.
The genus name Glycine was originally introduced by Carl Linnaeus (1737) in his first edition of Genera Plantarum. The word glycine is derived from the Greek - glykys (sweet) and likely refers to the sweetness of the pear-shaped ( apios in Greek) edible tubers produced by the native North American twining or climbing herbaceous yambean legume, Glycine apios, now known as Apios americana. The cultivated soybean first appeared in Species Plantarum, by Linnaeus, under the name Phaseolus max L. The combination Glycine max (L.) Merr., as proposed by Merrill in 1917, has become the valid name for this useful plant.
The genus Glycine Willd. is divided into two subgenera, Glycine and Soja. The subgenus Soja (Moench) FJ Herm. includes the cultivated soybean, Glycine max (L.) Merr., and the wild soybean, Glycine soja Sieb. & Zucc. Both species are annuals. Glycine soja is the wild ancestor of Glycine max, and grows wild in China, Japan, Korea, Taiwan and Russia. The subgenus Glycine consists of at least 25 wild perennial species: for example, Glycine canescens FJ Herm. and G. tomentella Hayata, both found in Australia and Papua New Guinea.
Like some other crops of long domestication, the relationship of the modern soybean to wild-growing species can no longer be traced with any degree of certainty. It is a cultural variety with a very large number of cultivars.
Soy varies in growth and habit. The height of the plant varies from less than 0.2 to 2.0 m (0.66 to 6.6 ft).
The pods, stems, and leaves are covered with fine brown or gray hairs. The leaves are trifoliolate, having three to four leaflets per leaf, and the leaflets are 6–15 cm (2.4–5.9 in) long and 2–7 cm (0.79–2.8 in) broad. The leaves fall before the seeds are mature. The inconspicuous, self-fertile flowers are borne in the axil of the leaf and are white, pink or purple.
The fruit is a hairy pod that grows in clusters of three to five, each pod is 3–8 cm long (1–3 in) and usually contains two to four (rarely more) seeds 5–11 mm in diameter.
Soybeans occur in various sizes, and in many hull or seed coat colors, including black, brown, blue, yellow, green and mottled. The hull of the mature bean is hard, water-resistant, and protects the cotyledon and hypocotyl (or "germ") from damage. If the seed coat is cracked, the seed will not germinate. The scar, visible on the seed coat, is called the hilum (colors include black, brown, buff, gray and yellow) and at one end of the hilum is the micropyle, or small opening in the seed coat which can allow the absorption of water for sprouting.
Remarkably, seeds such as soybeans containing very high levels of protein can undergo desiccation, yet survive and revive after water absorption. A. Carl Leopold, son of Aldo Leopold, began studying this capability at the Boyce Thompson Institute for Plant Research at Cornell University in the mid-1980s. He found soybeans and corn to have a range of soluble carbohydrates protecting the seed's cell viability. Patents were awarded to him in the early 1990s on techniques for protecting "biological membranes" and proteins in the dry state. Compare to tardigrades.
Many legumes ( alfalfa, clover, peas, beans, lentils, soybeans, peanuts and others) contain symbiotic bacteria called Rhizobia within nodules of their root systems. These bacteria have the special ability of fixing nitrogen from atmospheric, molecular nitrogen (N 2 ) into ammonia (NH 3 ). The chemical reaction is:
N 2 + 8 H + + 8 e − → 2 NH 3 + H 2
Ammonia is then converted to another form, ammonium (NH 4 + ), usable by (some) plants by the following reaction:
NH 3 + H + → NH 4 +
This arrangement means that the root nodules are sources of nitrogen for legumes, making them relatively rich in plant proteins.
Together, soybean oil and protein content account for about 60% of dry soybeans by weight (protein at 40% and oil at 20%). The remainder consists of 35% carbohydrate and about 5% ash. Soybean cultivars comprise approximately 8% seed coat or hull, 90% cotyledons and 2% hypocotyl axis or germ.
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.
The principal soluble carbohydrates of mature soybeans are the disaccharide sucrose (range 2.5–8.2%), the trisaccharide raffinose (0.1–1.0%) composed of one sucrose molecule connected to one molecule of galactose, and the tetrasaccharide stachyose (1.4 to 4.1%) composed of one sucrose connected to two molecules of galactose. While the oligosaccharides raffinose and stachyose protect the viability of the soybean seed from desiccation (see above section on physical characteristics) they are not digestible sugars, so contribute to flatulence and abdominal discomfort in humans and other monogastric animals, comparable to the disaccharide trehalose. Undigested oligosaccharides are broken down in the intestine by native microbes, producing gases such as carbon dioxide, hydrogen, and methane.
Since soluble soy carbohydrates are found in the whey and are broken down during fermentation, soy concentrate, soy protein isolates, tofu, soy sauce, and sprouted soybeans are without flatus activity. On the other hand, there may be some beneficial effects to ingesting oligosaccharides such as raffinose and stachyose, namely, encouraging indigenous bifidobacteria in the colon against putrefactive bacteria.
The insoluble carbohydrates in soybeans consist of the complex polysaccharides cellulose, hemicellulose, and pectin. The majority of soybean carbohydrates can be classed as belonging to dietary fiber.
Within soybean oil or the lipid portion of the seed is contained the phytosterols : stigmasterol (17–21%), sitosterol (53–56%) and campesterol (20–23%) accounting for 2.5% of the lipid fraction.
Saponins, a class of natural surfactants (soaps), are sterols that are present naturally in a wide variety of food-plants: vegetables, legumes, and cereals–ranging from beans and spinach to tomatoes, potatoes and oats. Whole soybeans contain from 0.17 to 6.16% saponins, 0.35 to 2.3% in defatted soy flour and 0.06 to 1.9% in tofu. Legumes such as soybean and chickpeas are the major source of saponins in the human diet. Sources of non-dietary saponins include alfalfa, sunflower, herbs and barbasco. Recent studies have shown that saponins are potential functional food ingredients because of their physiological properties.
Soy contains isoflavones like genistein and daidzein. It also contains glycitein, an O-methylated isoflavone which accounts for 5–10% of the total isoflavones in soy food products. Glycitein is a phytoestrogen with weak estrogenic activity, comparable to that of the other soy isoflavones.
For human consumption, soybeans must be cooked with "wet" heat to destroy the trypsin inhibitors ( serine protease inhibitors ). Raw soybeans, including the immature green form, are toxic to humans, swine, chickens, and in fact, all monogastric animals.
Soybeans are considered by many agencies to be a source of complete protein. A complete protein is one that contains significant amounts of all the essential amino acids that must be provided to the human body because of the body's inability to synthesize them. For this reason, soy is a good source of protein, amongst many others, 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 :
Soy protein products can be good substitutes for animal products because, unlike some other beans, soy offers a 'complete' protein profile. ... Soy protein products can replace animal-based foods—which also have complete proteins but tend to contain more fat, especially saturated fat—without requiring major adjustments elsewhere in the diet.
The gold standard for measuring protein quality, since 1990, is the Protein Digestibility Corrected Amino Acid Score (PDCAAS) and by this criterion soy protein is the nutritional equivalent of meat, eggs, and casein for human growth and health. Soybean protein isolate has a biological value of 74, whole soybeans 96, soybean milk 91, and eggs 97.
Soy protein is essentially identical to the protein of other legume seeds and pulses. Moreover, soybeans can produce at least twice as much protein per acre than any other major vegetable or grain crop besides hemp, five to 10 times more protein per acre than land set aside for grazing animals to make milk, and up to 15 times more protein per acre than land set aside for meat production.
Consumption of soy may also reduce the risk of colon cancer, possibly due to the presence of sphingolipids.
Soybeans are an importantly global crop, providing oil and protein. In the United States, the bulk of the harvest is solvent-extracted with hexane, and the "toasted" defatted soymeal (50% protein) then makes possible the raising of farm animals (eg chicken, hog, turkey) on an industrial scale never before seen in human history. A very small proportion of the crop is consumed directly by humans. Soybean products do, however, appear in a large variety of processed foods.
During World War II, soybeans became important in both North America and Europe chiefly as substitutes for other protein foods and as a source of edible oil. During World War II, the soybean was discovered as fertilizer by the United States Department of Agriculture. In the 1960–1 Dillon round of the General Agreement on Tariffs and Trade (GATT), the United States secured tariff-free access for its soybeans to the European market. In the 1960s, the United States exported over 90% of the world's soybeans. By 2005, the top soybeans exporters were Argentina (39% of world soybean exports), United States (37%) and Brazil (16%), while top importers were China (41% of world soybean imports), European Union (22%), Japan (6%) and Mexico (6%).
Cultivation is successful in climates with hot summers, with optimum growing conditions in mean temperatures of 20 to 30 °C (68 to 86 °F); temperatures of below 20 °C and over 40 °C (68 °F, 104 °F) retard growth significantly. They can grow in a wide range of soils, with optimum growth in moist alluvial soils with a good organic content. Soybeans, like most legumes, perform nitrogen fixation by establishing a symbiotic relationship with the bacterium Bradyrhizobium japonicum ( syn. Rhizobium japonicum ; Jordan 1982). For best results, though, an inoculum of the correct strain of bacteria should be mixed with the soybean (or any legume) seed before planting. Modern crop cultivars generally reach a height of around 1 m (3.3 ft), and take 80–120 days from sowing to harvesting.
The US, Argentina, Brazil, China and India are the world's largest soybean producers and represent more than 90% of global soybean production. The US produced 75 million tons of soybeans in 2000, of which more than one-third was exported. In the 2010–2011 production year, this figure is expected to be over 90 million tons.
The average worldwide yield for soybean crops, in 2010, was 2.5 tonnes per hectare. The three largest producers had an average nationwide soybean crop yields of about 3 tonnes per hectare. The most productive soybean farms in the world in 2010 were in Turkey, with a nationwide average farm yield of 3.7 tonnes per hectare. The world record for soybean yield is 10.8 tonnes per hectare, demonstrated in 2010 by Kip Cullers, a farmer in Purdy, Missouri. Kip Cullers claims the secret to his record breaking soybean crop yields year after year is attention to detail, proactive management style, irrigation, herbicides, keeping plants healthy and stress free for the entire growing season.
American soil scientist Dr. Andrew McClung, who first showed that the ecologically biodiverse savannah of the Cerrado region of Brazil could grow profitable soybeans, was awarded the 2006 World Food Prize on October 19, 2006.
In the USA human sewage sludge can be used as fertilizer to grow soybeans. Soybeans grown in sewage sludge likely contain elevated concentrations of metals. Soybean plants are vulnerable to a wide range of bacterial diseases, fungal diseases, viral diseases and parasites. Soybeans can be grown organically, that is, without the use of synthetic pesticides and fertilizers.
Further information: List of soybean diseases
Further information: Organic Beans
Soybeans were a crucial crop in eastern Asia long before written records. They remain a major crop in China, Japan, and Korea. Prior to fermented products such as soy sauce, tempeh, natto, and miso, soy was considered sacred for its beneficial effects in crop rotation.
The plants would be plowed under to clear the field of food crops. Soy was first introduced to Europe in the early 18th century and to British colonies in North America in 1765, where it was first grown for hay. Benjamin Franklin wrote a letter in 1770 mentioning sending soybeans home from England. Soybeans did not become an important crop outside of Asia until about 1910. In America, soy was considered an industrial product only, and was not used as a food prior to the 1920s. Soy was introduced to Africa from China in the late 19th century, and is now widespread across the continent.
Approximately 85% of the world's soybean crop is processed into soybean meal and vegetable oil. Soybeans can be broadly classified as "vegetable" (garden) or field (oil) types. Vegetable types cook more easily, have a mild, nutty flavor, better texture, are larger in size, higher in protein, and lower in oil than field types. Tofu and soy milk 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.
Among the legumes, the soybean, also classed as an oilseed, is preeminent for its high (38–45%) protein content as well as its high (20%) oil content. Soybeans are the second-most valuable agricultural export in the United States behind corn. The bulk of the soybean crop is grown for oil production, with the high-protein defatted and "toasted" soy meal used as livestock feed. A smaller percentage of soybeans are used directly for human consumption.
Immature soybeans may be boiled whole in their green pods and served with salt, under the Japanese name edamame ( 枝豆 edamame ). In English, these soybeans are generally known as "edamame" or "green vegetable soybeans".
In China, Japan, and Korea, the bean and products made from it are a popular part of the diet. The Chinese invented tofu (豆腐dòufu ), and also made use of several varieties of soybean paste as seasonings. Japanese foods made from soya include miso (味噌), nattō (納豆), kinako (黄粉) and edamame (枝豆). Also many kinds of food are produced using tofu such as atsuage, aburaage, and so on. In Korean cuisine, soybean sprouts, called kongnamul ( 콩나물 ), are also used in a variety of dishes, and are also 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, tofu ( đậu hũ or đậu phụ or tàu hũ ), soya sauce ( nước tương , literally: soya water), soya milk ( nước đậu in the North or sữa đậu nành in the South), and đậu hũ nước đường (tofu sweet soup).
The beans can be processed in a variety of ways. Common forms of soy (or soya) include soy meal, soy flour, soy milk, tofu, textured vegetable protein (TVP, which is made into a wide variety of vegetarian foods, some of them intended to imitate meat), tempeh, soy lecithin and soybean oil. Soybeans are also the primary ingredient involved in the production of soy sauce ( shoyu ).
Archer Daniels Midland (ADM) is among the largest processors of soybeans and soy products. ADM, along with Dow Chemical Company, DuPont and Monsanto Company, support the industry trade associations United Soybean Board and Soyfoods Association of North America. These trade associations have increased the consumption of soy products dramatically in recent years.
Soybean seed contains about 19% oil. To extract soybean oil from seed, the soybeans are cracked, adjusted for moisture content, rolled into flakes and solvent-extracted with commercial hexane. 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. The remaining soybean meal is used mainly as animal feed.
Soybean meal 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. Soybean meal is an essential element of the American production method of growing farm animals, such as poultry and swine, on an industrial scale that began in the 1930s; and more recently the aquaculture of catfish. Ninety-eight percent of the US soybean crop is used for livestock feed. Soybean meal is also used in lower-end dog foods.
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 production of soy concentrate and soy protein isolate.
Soy flour is made by roasting the soybean, removing the coat, and grinding into a flour. Soy flour is manufactured with different fat levels.
- 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 then defatted flour.
- 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 at the level of 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 then 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 (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, concludes that there are:
...no clinical concerns with respect to nutritional adequacy, sexual development, neurobehavioral development, immune development, or thyroid disease. SBIFs provide complete nutrition that adequately supports normal infant growth and development. FDA has accepted SBIFs as safe for use as the sole source of nutrition.
Soybeans can be processed to produce a texture and appearance similar to many other foods. For example, soybeans are the primary ingredient in many dairy product substitutes (eg, soy milk, margarine, soy ice cream, soy yogurt, soy cheese, and soy cream cheese) and meat substitutes (eg veggie burgers ). These substitutes are readily available in most supermarkets. Soy milk does not naturally contain significant amounts of digestible calcium. Many manufacturers of soy milk sell calcium-enriched products, as well. Soy is also used in tempeh : the beans (sometimes mixed with grain) are fermented into a solid cake.
Soy products also are used as a low-cost substitute in meat and poultry products. Food service, retail and institutional (primarily school lunch and correctional) facilities regularly use such "extended" products. 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.
Soybeans with black hulls are the beans used in Chinese fermented black beans, douchi, not the sometimes confused 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 dash board. Ford also informed in public relation releases that in 1935 over 5-million-acre (20,000 km 2 )s was dedicated to growing soybeans in the United States.
The Upjohn company used soybean stigmasterol as the starting raw material for the synthesis of cortisone.
According to James A. Duke, "The family of the yam Dioscoreaceae triggered North America's second revolution,the Sexual Revolution, by serving as the source for the steroid contraceptive." Today, it is the (yambean) legume family Fabaceae that has replaced Dioscorea sp. as the starting material for steroids. The days are over when Mexican barbasco fueled the steroid contraceptive industry. All commercially available steroids start with soy sterols. The soybean is now the prime source of steroidal drugs, including contraceptives and steroidal anti-inflammatory drugs.
In a 1985 interview with William Shurtleff of the Soy Info Center, AW Bill Schneider who started working at Upjohn in 1943 after leaving Central Soy, tells of the Upjohn company starting to make commercial products out of soy sterols in 1947–48. The first major product was progesterone and "then it really blossomed out with cortisone. "Upjohn made an industry out of soy sterols especially cortical steroids. He knew Percy Julian of Glidden well. Bill's professional career pivoted around commercializing soy sterols. He had more to do with its commercialization than anyone except for Percy Julian who started the idea at Glidden
Cattle are often fed soy. Spring grasses are rich in omega-3 fatty acids, whereas soy is predominantly omega-6. (From Wikipedia)
Juice recommended
- Smoothies job's-tears with cantaloupe
Vegetable juice is recommended
- Soy milk
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