Thesoybean,soy bean, orsoya bean (Glycine max)[4] is a species oflegume native toEast Asia, widely grown for its ediblebean. Soy is astaple crop, the world's most grown legume, and an important animal feed.[5]
Soy is a key source of food, useful both for its protein and oil content.Soybean oil is widely used in cooking, as well as in industry. Traditional unfermented food uses of soybeans includeedamame, as well assoy milk, from whichtofu andtofu skin are made. Fermented soy foods includesoy sauce,fermented bean paste,nattō, andtempeh. Fat-free (defatted) soybean meal is a significant and cheap source of protein for animal feeds and manypackaged meals.[5] For example, soybean products, such astextured vegetable protein (TVP), are ingredients in many meat anddairy substitutes.[5][6] Soy based foods are traditionally associated with East Asian cuisines, and still constitute a major part of East Asian diets, but processed soy products are increasingly used in Western cuisines.
Soy wasdomesticated from thewild soybean(Glycine soja) in north-central China between 6,000 and 9,000 years ago.[7] Brazil and the United States lead the world in modern soy production. The majority of soybeansare genetically modified,[8] usually for either insect, herbicide, or drought resistance. Three-quarters of soy is used to feed livestock, which in turn go to feed humans. Increasing demand for meat has substantially increased soy production since the 1980s, and contributed to deforestation in theAmazon.
Soybeans contain significant amounts ofphytic acid,dietary minerals andB vitamins. Soy may reduce the risk of cancer and heart disease. Some people areallergic to soy. Soy is acomplete protein and therefore important in the diets of manyvegetarians andvegans. The association of soy with vegans and the misconception that soy increasesestrogen production have led to "soy boy" being used as a derogatory term.[9]
Etymology
The word "soy" derives from the Japanesesoi, a regional variant ofshōyu,[10] which in turn comes from the Chinesejiangyou (醬油), meaning "soy sauce".[11]
The name of the genus,Glycine, comes fromLinnaeus. When naming the genus, Linnaeus observed that one of the species formerly within the genus, which has since been reclassified to the genusApios, had a sweet root. Based on the sweetness, the Greek word for sweet,glykós, was Latinized.[12] The genus name is not related to the amino acidglycine.[citation needed]
Like most plants, soybeans grow in distinctmorphological stages as they develop from seeds into fully mature plants.
Germination
The first stage of growth isgermination, a method which first becomes apparent as a seed'sradicle emerges.[13] This is the first stage of root growth and occurs within the first 48 hours under ideal growing conditions. The firstphotosynthetic structures, thecotyledons, develop from thehypocotyl, the first plant structure to emerge from the soil. These cotyledons both act as leaves and as a source of nutrients for the immature plant, providing the seedling nutrition for its first 7 to 10 days.[13]
Fruits/pods
Maturation
The first true leaves develop as a pair ofsingle blades.[13] Subsequent to this first pair, maturenodes form compound leaves with three blades. Maturetrifoliolate leaves, having three to fourleaflets per leaf, are often between 6 and 15 cm (2+1⁄2 and 6 in) long and 2 and 7 cm (1 and 3 in) broad. Under ideal conditions, stem growth continues, producing new nodes every four days. Before flowering, roots can grow2 cm (3⁄4 in) per day. Ifrhizobia are present,root nodulation begins by the time the third node appears. Nodulation typically continues for 8 weeks before thesymbiotic infection process stabilizes.[13] The final characteristics of a soybean plant are variable, with factors such as genetics,soil quality, and climate affecting its form; however, fully mature soybean plants are generally between 50 and 125 cm (20 and 50 in) in height[14] and have rooting depths between 75 and 150 cm (30 and 60 in).[15]
Flowering
Flowering istriggered by day length, often beginning once days become shorter than 12.8 hours.[13] This trait is highly variable however, with differentvarieties reacting differently to changing day length.[16] Soybeans form inconspicuous, self-fertile flowers which are borne in theaxil of the leaf and are white, pink or purple. Though they do not require pollination, they are attractive to bees, because they produce nectar that is high in sugar content.[17] Depending on the soybean variety, node growth may cease once flowering begins. Strains that continue nodal development after flowering are termed "indeterminates" and are best suited to climates with longer growing seasons.[13] Often soybeans drop their leaves before the seeds are fully mature.
Small, purple flowers
The fruit is a hairy pod that grows in clusters of three to five, each pod is 3–8 cm (1–3 in) long and usually contains two to four (rarely more)seeds 5–11 mm in diameter. Soybean seeds come in a wide variety of sizes andhull colors such as black, brown, yellow, and green.[14] Variegated and bicolored seed coats are also common.
Seed resilience
Bean varieties
The hull of the mature bean is hard, water-resistant, and protects thecotyledon andhypocotyl (or "germ") from damage. If the seed coat is cracked, the seed will notgerminate. The scar, visible on the seed coat, is called thehilum (colors include black, brown, buff, gray and yellow) and at one end of the hilum is themicropyle, or small opening in the seed coat which can allow the absorption of water for sprouting.
Some seeds such as soybeans containing very high levels ofprotein can undergodesiccation, yet survive and revive after water absorption.A. Carl Leopold began studying this capability at theBoyce Thompson Institute for Plant Research atCornell University in the mid-1980s. He found soybeans and corn to have a range of solublecarbohydrates protecting the seed's cell viability.[18] Patents were awarded to him in the early 1990s on techniques for protecting biological membranes and proteins in the dry state.
The genusGlycine may be divided into two subgenera,Glycine andSoja. The subgenusSoja includes the cultivated soybean,G. max, and the wild soybean, treated either as a separate speciesG. soja,[21] or as the subspeciesG. max subsp.soja.[2] The cultivated and wild soybeans areannuals. The wild soybean is native toChina,Japan,Korea andRussia.[21] The subgenusGlycine consists of at least 25 wildperennial species: for example,G. canescens andG. tomentella, both found inAustralia andPapua New Guinea.[22][23] Perennial soybean (Neonotonia wightii) belongs to a different genus. It originated in Africa and is now a widespread pasture crop in the tropics.[24][25][26]
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.[27] It is acultigen with a very large number ofcultivars.[28]
Soybeans are globally important agricultural crops, grown as a major source of protein andoil. It prefers fertile, well-drained soils and requires a warm temperate climate with adequate rainfall or irrigation. Soybeans are mainly grown in the United States, Brazil, and Argentina.[31]
It is usually planted in straight rows using modern machinery, and pests and weeds must be controlled to maintain the crop. After maturity, it is harvested using mechanized harvesting machines. Soybeans are used in the production of many food and industrial products, such astofu, oils, and feed, in addition to their role in improving soil fertility byfixing nitrogen.
Conditions
Mature row planted soy in Argentina
Cultivation is successful in climates with hot summers, with optimum growing conditions in mean temperatures of 20 to 30 °C (70 to 85 °F); temperatures of below 20 °C (70 °F) and over 40 °C (105 °F) stunt growth significantly. They can grow in a wide range of soils, with optimum growth in moistalluvial soils with good organic content. Soybeans, like most legumes, performnitrogen fixation by establishing asymbiotic relationship with the bacteriumBradyrhizobium japonicum (syn.Rhizobium japonicum; Jordan 1982). This ability to fix nitrogen allows farmers to reduce nitrogenfertilizer use and increase yields when growing other crops inrotation with soy.[32] There may be some trade-offs, however, in the long-term abundance oforganic material in soils where soy and other crops (for example,corn) are grown in rotation.[33] 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 cropcultivars generally reach a height of around 1 m (3 ft), and take 80–120 days from sowing to harvesting.
Humansewage sludge can be used as fertilizer to grow soybeans. Soybeans grown in sewage sludge likely contain elevated concentrations of metals.[38][39]
TheJapanese beetle (Popillia japonica) poses a significant threat to agricultural crops, including soybeans, due to its voracious feeding habits. Found commonly in both urban and suburban areas, these beetles are frequently observed in agricultural landscapes where they can cause considerable damage to crops like corn, soybeans, and various fruits.[41][42]
Soybean cyst nematode (SCN) is the worst pest of soybean in the US. Losses of 30%[43] or 40%[RM 1] are common even without symptoms.
Soybeans are consumed bywhitetail deer which may damage soybean plants through feeding, trampling and bedding, reducingcrop yields by as much as 15%.[45]Groundhogs are also a common pest in soybean fields, living in burrows underground and feeding nearby. One den of groundhogs can consume a tenth to a quarter of an acre of soybeans.[46]Chemical repellents orfirearms are effective for controlling pests in soybean fields.[45][46]
The vast majority of cultivars in the US havesoybean cyst nematode resistance (SCN resistance), but rely ononly one breeding line (PI 88788) as their sole source of resistance.[RM 2] (The resistance genes provided by PI 88788,Peking, andPI 90763 werecharacterized in 1997.)[51] As a result, for example, in 2012 only 18 cultivars out of 807 recommended by theIowa State University Extension had any ancestry outside of PI 88788. By 2020 the situation was still about the same: Of 849 there were 810 with some ancestry from PI 88788,[52][53] 35 from Peking, and only 2 from PI 89772. (On the question of exclusively PI 88788 ancestry, that number was not available for 2020.)[53] That was speculated to be in 2012[RM 3]—and was clearly by 2020[52]—producing SCN populations that are virulent on PI 88788.
In 2020, world production of soybeans was over 353 million tonnes, led by Brazil and the United States combined with 66% of the total (table). Production has dramatically increased across the globe since the 1960s, but particularly in South America after a cultivar that grew well in low latitudes was developed in the 1980s.[55] The rapid growth of the industry has been primarily fueled by large increases inworldwide demand for meat products, particularly in developing countries like China, which alone accounts for more than 60% of imports.[56] Soy is astaple crop; global soy production accounts for four times more legume production than all other legumes combined.[57]
In spite of the Amazon "Soy Moratorium", soy production continues to play a significant role indeforestation when its indirect impacts are taken into account, as land used to grow soy continues to increase. This land either comes frompasture land (which increasingly supplants forested areas), or areas outside the Amazon not covered by the moratorium, such as theCerrado region. Roughly one-fifth of deforestation can be attributed to expanding land use to produce oilseeds, primarily for soy andpalm oil, whereas the expansion ofbeef production accounts for 41%. The main driver of deforestation is the global demand for meat, which in turn requires huge tracts of land to grow feed crops for livestock.[58] Around 80% of the global soybean crop is used to feed livestock.[59]
Soybeans were a crucial crop in East Asia long before written records began.[60] The origin of soy cultivation remains scientifically debated. The closest living relative of the soybean isGlycine soja (previously calledG. ussuriensis), a legume native to central China.[61] Genomic data increasingly supports a single domestication event in north-central China between 6,000 and 9,000 years ago, although some evidence suggests a more complex scenario involving low-intensity pre-domestication cultivation across multiple locations in East Asia, followed by the eventual dominance of the Chinese lineage.[7]
There is evidence for soybean domestication between 7000 and 6600 BC in China, between 5000 and 3000 BC in Japan and 1000 BC in Korea.[62] The first unambiguously domesticated,cultigen-sized soybean was discovered in Korea at theMumun-period Daundong site.[62][63] Prior tofermented products such as fermented black soybeans (douchi),jiang (Chinese miso),soy sauce,tempeh,nattō, andmiso, soy was considered sacred for its beneficial effects incrop rotation, and it was eaten by itself, and asbean curd andsoy milk.
Soybeans were introduced toJava inMalay Archipelago circa 13th century or probably earlier. By the 17th century through their trade with Far East, soybeans and its products were traded by European traders (Portuguese, Spanish, and Dutch) in Asia, and reached Indian Subcontinent by this period.[citation needed] By the 18th century, soybeans were introduced to the Americas and Europe from China. Soy was introduced to Africa from China in the late 19th century, and is now widespread across the continent.
Soy was most likely domesticated 6,000–9,000 years ago in the region between theYellow River and theHuai River in China.[7] The earliest documented evidence for the use ofGlycine of any kind comes from charred plant remains of wild soybean recovered from Jiahu inHenan province, aNeolithic site occupied between 9,000 and 7,800 years ago.[62] An abundance of archaeological charred soybean specimens have been found centered around this region.[64]
Soybeans became an important crop by theZhou dynasty (c. 1046–256 BC) in China. According to an ancient Chinese myth, in 2853 BC, the legendaryEmperor Shennong of China proclaimed that five plants were sacred: soybeans, rice, wheat, barley, andmillet.[65] Early Chinese records mention that soybeans were a gift from the region of theYangtze River delta and Southeast China.[66] However, there is no archaeological evidence that soybeans were domesticated in southern China, and it appears that soy was unknown there prior to theHan dynasty.[62]
The oldest preserved soybeans resembling modern varieties in size and shape were found inarchaeological sites inKorea dated about 1000 BC.[66][67]Radiocarbon dating of soybean samples recovered throughflotation during excavations at the EarlyMumun period Okbang site in Korea indicated soybean was cultivated as a food crop in around 1000–900 BC.[67] Soybeans from the Jōmon period in Japan from 3000 BC[62] are also significantly larger than wild varieties.[62][68] The earliest Japanese textual reference to the soybean is in the classicKojiki (Records of Ancient Matters), which was completed in 712 CE.
Southeast Asia
Soybeans were mentioned askadêlê (modernIndonesian term:kedelai)[69] in anold Javanese manuscript, SeratSri Tanjung, which dates to 12th- to 13th-centuryJava.[70] By the 13th century, the soybean had arrived and cultivated in Indonesia; it probably arrived much earlier however, carried by traders or merchants from Southern China.[71]
The earliest known reference to it as "tempeh" appeared in 1815 in theSerat Centhini manuscript.[72] The development of tempeh fermented soybean cake probably took place earlier, circa 17th century in Java.
Indian subcontinent
By the 1600s, soy sauce spread from southern Japan across the region through theDutch East India Company (VOC).
From a high-altitude area ofNepalYoung plants inIndia
While the origins and history of Soybean cultivation in theEastern Himalayas is debated, it was potentially introduced from southernChina, more specificallyYunnan province.[73][74] Alternatively, it could have reached here through traders fromIndonesia viaMyanmar.Northeast India is viewed as a passive micro-centre within the soybean secondary gene centre. Central India is considered a tertiary gene centre particularly the area encompassing Madhya Pradesh which is also the country largest soybean producer.[74]
Iberia
Vocabvlario da Lingoa de Iapam, a Japanese-Portuguese dictionary, was compiled and published in 1603 by Jesuit priests in Nagasaki. It contains short but clear definitions for about 20 words related to soyfoods—the first in any European language.
The Luso-Hispanic traders were familiar with soybeans and soybean product through their trade with Far East since at least the 17th century. However, it was not until the late 19th century that the first attempt to cultivate soybeans in the Iberian peninsula was undertaken. In 1880, the soybean was first cultivated in Portugal in theBotanical Gardens at Coimbra (Crespi 1935).
In about 1910 in Spain the first attempts at Soybean cultivation were made by the Count of San Bernardo, who cultivated soybeans on his estates at Almillo (in southwest Spain) about 48 miles east-northeast of Seville.[75]
North America
Soybeans were first introduced to North America from China in 1765, bySamuel Bowen, a formerEast India Company sailor who had visited China in conjunction withJames Flint, the first Englishman legally permitted by the Chinese authorities to learn Chinese.[76] The first "New World" soybean crop was grown onSkidaway Island, Georgia, in 1765 by Henry Yonge from seeds given him by Samuel Bowen.[77][78][79] Bowen grew soy nearSavannah, Georgia, possibly using funds from Flint, and made soy sauce for sale to England.[80] Although soybean was introduced into North America in 1765, for the next 155 years, the crop was grown primarily forforage.[81]
In 1831, the first soy product "a few dozen India Soy" [sauce] arrived in Canada. Soybeans were probably first cultivated in Canada by 1855, and definitely in 1895 atOntario Agricultural College.[82]
It was not untilLafayette Mendel andThomas Burr Osborne showed that the nutritional value of soybean seeds could be increased by cooking, moisture or heat, that soy went from a farm animal feed to a human food.[83][84]
William Joseph Morse is considered the "father" of modern soybean agriculture in America. In 1910, he andCharles Piper began to popularize what was regarded as a relatively unknown Oriental peasant crop in America into a "golden bean", with the soybean becoming one of America's largest and most nutritious farm crops.[85][86][87]
Prior to the 1920s in the US, the soybean was mainly aforage crop, a source of oil, meal (for feed) and industrial products, with very little used as food. However, it took on an important role after World War I. During theGreat Depression, the drought-stricken (Dust Bowl) regions of the United States were able to use soy to regenerate their soil because of its nitrogen-fixing properties. Farms were increasing production to meet with government demands, andHenry Ford became a promoter of soybeans.[88] In 1931, Ford hired chemistsRobert Boyer and Frank Calvert to produceartificial silk. They succeeded in making a textile fiber of spun soy protein fibers, hardened or tanned in aformaldehyde bath, which was given the nameAzlon. It never reached the commercial market. Soybean oil was used byFord inpaint for the automobiles,[89] as well as a fluid for shock absorbers.
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 the war, the soybean was discovered asfertilizer due tonitrogen fixation by theUnited States Department of Agriculture.
Prior to the 1970s, Asian-Americans and Seventh-Day Adventists were essentially the only users of soy foods in the United States.[90] "The soy foods movement began in small pockets of the counterculture, notably the Tennessee commune named simplyThe Farm, but by the mid-1970s a vegetarian revival helped it gain momentum and even popular awareness through books such asThe Book of Tofu."[91]
Although practically unseen in 1900, by 2000 soybean plantings covered more than 70 million acres,[92] second only to corn, and it became America's largest cash crop.[citation needed] In 2021, 87,195,000 acres were planted, with the largest acreage in the states of Illinois, Iowa, and Minnesota.[93]
Caribbean and West Indies
The soybean arrived in the Caribbean in the form of soy sauce made by Samuel Bowen in Savannah, Georgia, in 1767. It remains only a minor crop there, but its uses for human food are growing steadily.[94]
Mediterranean area
The soybean was first cultivated in Italy by 1760 in the Botanical Garden of Turin. During the 1780s, it was grown in at least three other botanical gardens in Italy.[95] The first soybean product, soy oil, arrived inAnatolia during 1909 underOttoman Empire.[96] The first clear cultivation occurred in 1931.[96] This was also the first time that soybeans were cultivated in Middle East.[96] By 1939, soybeans were cultivated in Greece.[97][98]
Australia
Wild soybeans were discovered in northeastern Australia in 1770 by explorers Banks and Solander. In 1804, the first soyfood product ("Fine India Soy" [sauce]) was sold in Sydney. In 1879, the first domesticated soybeans arrived in Australia, a gift of the Minister of the Interior Department, Japan.[99]
France
The soybean was first cultivated in France by 1779 (and perhaps as early as 1740). The two key early people and organizations introducing the soybean to France were the Society of Acclimatization (starting in 1855) andLi Yu-ying (from 1910). Li started a large tofu factory, where the first commercial soyfoods in France were made.[100]
Africa
The soybean first arrived in Africa via Egypt in 1857.[101] Soya Meme (Baked Soya) is produced in the village called Bame Awudome nearHo, the capital of theVolta Region ofGhana, by theEwe people of Southeastern Ghana and southern Togo.
Central Europe
In 1873, ProfessorFriedrich J. Haberlandt first became interested in soybeans when he obtained the seeds of 19 soybean varieties at theVienna World Exposition (Wiener Weltausstellung). He cultivated these seeds in Vienna, and soon began to distribute them throughout Central and Western Europe. In 1875, he first grew the soybeans in Vienna, then in early 1876 he sent samples of seeds to seven cooperators in central Europe, who planted and tested the seeds in the spring of 1876, with good or fairly good results in each case.[102] Most of the farmers who received seeds from him cultivated them, then reported their results. Starting in February 1876, he published these results first in various journal articles, and finally in hismagnum opus, Die Sojabohne (The Soybean) in 1878.[102] In northern Europe,lupin (lupine) is known as the "soybean of the north".[103]
Central Asia
The soybean is first in cultivated Transcaucasia in Central Asia in 1876, by the Dungans. This region has never been important for soybean production.[104]
Central America
The first reliable reference to the soybean in this region dates from Mexico in 1877.[105]
South America
The soybean first arrived in South America in Argentina in 1882.[106]
Andrew McClung showed in the early 1950s that with soil amendments theCerrado region of Brazil would grow soybeans.[107] In June 1973, when soybean futures markets mistakenly portended a major shortage, theNixon administration imposed an embargo on soybean exports. It lasted only a week, but Japanese buyers felt that they could not rely on U.S. supplies, and the rival Brazilian soybean industry came into existence.[108][88] This led Brazil to become the world's largest producer of soybeans in 2020, with 131 million tons.[109]
Industrial soy production in South America is characterized by wealthy management who live far away from the production site which they manage remotely. In Brazil, these managers depend heavily on advanced technology and machinery, and agronomic practices such as zero tillage, high pesticide use, and intense fertilization. One contributing factor is the increased attention on the BrazilianCerrado inBahia, Brazil by US farmers in the early 2000s. This was due to rising values of scarce farmland and high production costs in the US Midwest. There were many promotions of the Brazilian Cerrado by US farm producer magazines and market consultants who portrayed it as having cheap land with ideal production conditions, with infrastructure being the only thing it was lacking. These same magazines also presented Brazilian soy as inevitably out-competing American soy. Another draw to investing was the insider information about the climate and market in Brazil. A few dozen American farmers purchased varying amounts of land by a variety of means including finding investors and selling off land holdings. Many followed theethanol company model and formed anLLC with investments from neighboring farmers, friends, and family while some turned to investment companies. Some soy farmers eitherliquidated their Brazilian assets or switched to remote management from the US to return to farming there and implement new farming and business practices to make their US farms more productive. Others planned to sell their now expensive Bahia land to buy land cheaper land in the frontier regions ofPiauí orTocantins to create more soybean farms.[110]
Different varieties of soybeans being grown together
Soybeans are one of the "biotech food" crops that have beengenetically modified, and genetically modified soybeans are being used in an increasing number of products. In 1995,Monsanto company introducedglyphosate-tolerant soybeans that have been genetically modified to be resistant to Monsanto'sglyphosate herbicides through substitution of theAgrobacterium sp. (strain CP4)gene EPSP (5-enolpyruvyl shikimic acid-3-phosphate) synthase. The substituted version is not sensitive toglyphosate.[117]
In 1997, about 8% of all soybeans cultivated for the commercial market in the United States were genetically modified. In 2010, the figure was 93%.[118] As with other glyphosate-tolerant crops, concern is expressed over damage tobiodiversity.[119] A 2003 study[120] concluded the "Roundup Ready" (RR) gene had been bred into so many different soybean cultivars, there had been little decline in genetic diversity, but "diversity was limited among elite lines from some companies".
The widespread use of such types of GM soybeans in the Americas has caused problems with exports to some regions. GM crops require extensive certification before they can be legally imported into theEuropean Union, where there is considerable supplier and consumer reluctance to use GM products for consumer or animal use. Difficulties withcoexistence and subsequent traces of cross-contamination of non-GM stocks have caused shipments to be rejected and have put a premium on non-GM soy.[121]
A 2006United States Department of Agriculture report found the adoption of genetically engineered (GE) soy, corn and cotton reduced the amount of pesticides used overall, but did result in a slightly greater amount ofherbicides used for soy specifically. The use of GE soy was also associated with greaterconservation tillage, indirectly leading to better soil conservation, as well as increased income from off-farming sources due to the greater ease with which the crops can be managed. Though the overall estimated benefits of the adoption of GE soybeans in the United States was $310 million, the majority of this benefit was experienced by the companies selling the seeds (40%), followed by biotechnology firms (28%) and farmers (20%).[122] The patent on glyphosate-tolerant soybeans expired in 2014,[123] so benefits can be expected to shift.[124]
Allergy to soy is common, and the food is listed with other foods that commonly cause allergy, such as milk, eggs, peanuts, tree nuts, and shellfish. The problem has been reported among younger children, and the diagnosis of soy allergy is often based on symptoms reported by parents and results of skin tests or blood tests for allergy. Only a few reported studies have attempted to confirm allergy to soy by direct challenge with the food under controlled conditions.[125] It is very difficult to give a reliable estimate of the true prevalence of soy allergy in the general population. To the extent that it does exist, soy allergy may cause cases ofurticaria andangioedema, usually within minutes to hours of ingestion. In rare cases, trueanaphylaxis may also occur. The reason for the discrepancy is likely that soy proteins, the causative factor inallergy, are far less potent at triggering allergy symptoms than the proteins of peanut and shellfish.[126] An allergy test that is positive demonstrates that the immune system has formed IgE antibodies to soy proteins. However, this is only a factor when soy proteins reach the blood without being digested, in sufficient quantities to reach a threshold to provoke actual symptoms.
Soy can also trigger symptoms viafood intolerance, a situation where no allergic mechanism can be proven. One scenario is seen in very young infants who have vomiting anddiarrhoea when fed soy-based formula, which resolves when the formula is withdrawn. Older infants can suffer a more severe disorder with vomiting, diarrhoea that may be bloody,anemia, weight loss and failure to thrive. The most common cause of this unusual disorder is a sensitivity to cow's milk, but soy formulas can also be the trigger. The precise mechanism is unclear and it could be immunologic, although not through the IgE-type antibodies that have the leading role in urticaria and anaphylaxis. However, it is also self-limiting and will often disappear in thetoddler years.[127]
In theEuropean Union, identifying the presence of soy either as an ingredient or unintended contaminant in packaged food is compulsory. The regulation (EC) 1169/2011 on food-labeling lists 14 allergens, including soy, in packaged food must be clearly indicated on the label as part of the list of ingredients, using a distinctive typography (such as bold type or capital letters).[128]
Thyroid function
One review noted that soy-based foods may inhibit absorption of thyroid hormone medications required for treatment ofhypothyroidism.[129] A 2015 scientific review by theEuropean Food Safety Authority concluded that intake of isoflavones from supplements did not affect thyroid hormone levels inpostmenopausal women.[130]
Uses
Breakdown of what the world's soy was used for in 2018Tofu andsoy sauce, both made from soy beans
Among thelegumes, 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.[131] 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.[132]
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, andsoy 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.
A 100-gram reference quantity of raw soybeans supplies 1,866 kilojoules (446 kilocalories) offood energy and are 9% water, 30%carbohydrates, 20% totalfat and 36%protein.Peanuts are the onlylegumes with a higher fat content (48%) and calorie count (2,385 kJ). They contain less carbohydrates (21%), protein (25%) and dietary fiber (9%).
For human consumption, soybeans must be processed prior to consumption–either by cooking, roasting, or fermenting–to destroy thetrypsin inhibitors (serine protease inhibitors).[135] Raw soybeans, including the immature green form, are toxic to allmonogastric animals.[136]
Most soy protein is a relatively heat-stable storage protein. This heat stability enables soy food products requiring high temperature cooking, such astofu,soy milk andtextured vegetable protein (soy flour) to be made.Soy protein is essentially identical to the protein of otherlegume seeds andpulses.[137][138]
Soy is a good source of protein for vegetarians andvegans or for people who want to reduce the amount of meat they eat, according to theUS Food and Drug Administration:[139]
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.
Although soybeans have high protein content, soybeans also contain high levels ofprotease inhibitors, which can prevent digestion.[140] Protease inhibitors are reduced by cooking soybeans, and are present in low levels in soy products such astofu andsoy milk.[140]
Allspermatophytes, 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 theseglobulin proteins. S denotesSvedberg, sedimentation coefficients. Oats and rice are anomalous in that they also contain a majority of soybean-like protein.[142] Cocoa, for example, contains the 7S globulin, which contributes to cocoa/chocolate taste and aroma,[143][144][145] whereas coffee beans (coffee grounds) contain the 11S globulin responsible for coffee's aroma and flavor.[146][147]
Vicilin and legumin proteins belong to thecupin 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.[148]
Peanuts, for instance, contain 20% 2S albumin but only 6% 7S globulin and 74% 11S.[149] It is the high 2S albumin and low 7S globulin that is responsible for the relatively low lysine content of peanut protein compared to soy protein.
Carbohydrates
The principal solublecarbohydrates of mature soybeans are the disaccharidesucrose (range 2.5–8.2%), the trisaccharideraffinose (0.1–1.0%) composed of one sucrose molecule connected to one molecule ofgalactose, and the tetrasaccharidestachyose (1.4 to 4.1%) composed of one sucrose connected to two molecules of galactose.[citation needed] While theoligosaccharides 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 toflatulence and abdominal discomfort in humans and othermonogastric animals, comparable to the disaccharidetrehalose. Undigested oligosaccharides are broken down in the intestine by native microbes, producing gases such ascarbon dioxide,hydrogen, andmethane.
Since soluble soy carbohydrates are found in thewhey 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 indigenousbifidobacteria in the colon against putrefactive bacteria.
The insoluble carbohydrates in soybeans consist of the complex polysaccharidescellulose,hemicellulose, andpectin. The majority of soybean carbohydrates can be classed as belonging todietary fiber.
Soy containsisoflavones—polyphenolic compounds, produced by legumes including peanuts andchickpeas. Isoflavones are closely related toflavonoids found in other plants, vegetables and flowers.[155]
Soy contains thephytoestrogencoumestans, also are found in beans and split-peas, with the best sources being alfalfa, clover, and soybean sprouts.Coumestrol, an isoflavonecoumarin derivative, is the only coumestan in foods.[156][157]
Saponins, a class of naturalsurfactants (soaps), are sterols that are present in small amounts in variousplant foods, including soybeans, otherlegumes, and cereals, such as oats.[158][159]
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 adry 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.
A raw yellow dent corn B raw unenriched long-grain white rice C raw hard red winter wheat D raw potato with flesh and skin E raw cassava F raw green soybeans G raw sweet potato H raw sorghum Y raw yam Z raw plantains /* unofficial
Soybean seed contains 18–19% oil.[161] To extract soybean oil from seed, the soybeans are cracked, adjusted for moisture content, rolled into flakes, and solvent-extracted with commercial hexane.[162] 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.
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' (amisnomer because the heat treatment is with moist steam) and ground in ahammer mill. Ninety-seven percent of soybean meal production globally is used as livestock feed.[161] Soybean meal is also used in somedog foods.[163]
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 livestockfeed, soybean meal provides around 60% of the protein fed to livestock.[164] 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.[165]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.[166][167]
In addition to their use in livestock feed, soybean products are widely used for human consumption. Common soybean products includesoy sauce,soy milk,tofu,soy meal,soy flour,textured vegetable protein (TVP),soy curls,tempeh, soylecithin andsoybean oil. Soybeans may also be eaten with minimal processing, for example, in the Japanese foodedamame (枝豆,edamame), in which immature soybeans are boiled whole in their pods and served withsalt.
In China, Japan, Vietnam andKorea, soybean and soybean products are a standard part of the diet.[168]Tofu (豆腐dòufu) is thought to have originated in China, along withsoy sauce and several varieties ofsoybean paste used as seasonings.[citation needed] Japanese foods made from soya includemiso (味噌),nattō (納豆),kinako (黄粉) andedamame (枝豆), as well as products made with tofu such asatsuage andaburaage. 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. InKorean cuisine, soybean sprouts (콩나물 [ko]kongnamul) are used in a variety of dishes, and soybeans are the base ingredient indoenjang,cheonggukjang andganjang. In Vietnam, soybeans are used to make soybean paste (tương) in the North with the most popular products aretương Bần,tương Nam Đàn,tương Cự Đà as a garnish forphở andgỏi cuốn dishes, as well as tofu (đậu hũ orđậu phụ ortàu hũ), soy sauce (nước tương), soy milk (nước đậu in the North orsữa đậu nành in the South), andđậu hũ nước đường (tofu sweet soup).
Flour
Wikimedia Commons has media related toSoybean 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 minimizedenaturation of the protein to retain a highprotein dispersibility index, for uses such asfood extrusion oftextured vegetable protein.[169] 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.[170] Alternatively, raw soy flour omits the roasting step.
Defatted soy flour is obtained fromsolventextracted flakes and contains less than 1% oil.[170]
"Natural or full-fat soy flour is made from unextracted, dehulled beans and contains about 18% to 20% oil."[170] Its high oil content requires the use of a specialized Alpine Fine Impact Mill to grind rather than the usualhammer 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.[171][172] Full-fat soy flour is a component ofCornell bread.[173][174][175]
Low-fat soy flour is made by adding some oil back into defatted soy flour. Fat levels range from 4.5% to 9%.[170]
High-fat soy flour can also be produced by adding back soybean oil to defatted flour, usually at 15%.[176]
Soy lecithin can be added (up to 15%) to soy flour to make lecithinated soy flour. It increases dispersibility and gives it emulsifying properties.[170]
Soy flour has 50% protein and 5% fiber. It has higher levels of protein, thiamine, riboflavin, phosphorus, calcium, and iron thanwheat flour. It does not containgluten.[170] As a result,yeast-raisedbreads made with soy flour are dense in texture. Among many uses, soy flour thickens sauces, preventsstaling 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.[170]
Soy grits are similar to soy flour, except the soybeans have been toasted and cracked into coarse pieces.
Soy-basedinfant 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 avegan 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.[177] 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.[178][179][180] One of these studies, published in theJournal of Nutrition,[180] 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 manydairy product substitutes (e.g.,soy milk,margarine, soy ice cream,soy yogurt,soy cheese, and soy cream cheese) and meat alternatives (e.g.veggie burgers). These substitutes are readily available in most supermarkets. Soy milk does not naturally contain significant amounts of digestiblecalcium. Many manufacturers of soy milk sell calcium-enriched products, as well.
Soy products also are used as a low-cost substitute for meat and poultry products.[181][182] 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 substitutetextured vegetable protein has been used for more than 50 years as a way of inexpensively extendingground beef without reducing its nutritional value.[6][183][184]
Soy nut butter
The soybean is used to make a product called soynut butter which is similar in texture to peanut butter.[185]
Sweetened soybean
Sweet-boiled beans are popular in Japan and Korea, and the sweet-boiled soybeans are called "Daizu noNimame [ja]" in Japan and Kongjorim (Korean:콩조림) in Korea. Sweet-boiled beans are even used in sweetened buns, especially inMame Pan [ja].
Roasted and ground soybeans can be a caffeine-free substitute forcoffee. 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.[186]
Other products
Soy candles for sale in Texas
Soybeans with black hulls are used in Chinese fermented black beans,douchi, not to be confused withblack 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 ofbiodiesel in the United States, accounting for 80% of domestic biodiesel production.[187] Soybeans have also been used since 2001 as fermenting stock in the manufacture of a brand ofvodka.[188] 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 km2) was dedicated to growing soybeans in the United States.[189]
Potential health benefits
Reducing risk of cancer
According to theAmerican 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 soydietary supplements (e.g., as a pill or capsule) has any effect on health or cancer risk.[190]
Although considerable research has examined the potential for soy consumption to lower the risk ofbreast cancer in women, as of 2016 there is insufficient evidence to reach a conclusion about a relationship between soy consumption and any effects on breast cancer.[155] A 2011meta-analysis stated: "Our study suggests soy isoflavones intake is associated with a significant reduced risk of breast cancer incidence in Asian populations, but not in Western populations."[195]
Gastrointestinal and colorectal cancer
Reviews of preliminary clinical trials on people withcolorectal orgastrointestinal cancer suggest that soy isoflavones may have a slight protective effect against such cancers.[191][192]
Prostate cancer
A 2016 review concluded that "current evidence fromobservational studies and small clinical trials is not robust enough to understand whether soy protein orisoflavone supplements may help prevent or inhibit the progression ofprostate cancer."[155] A 2010 review showed that neither soy foods nor isoflavone supplements alter measures of bioavailabletestosterone orestrogen concentrations in men.[196] Soy consumption has been shown to have no effect on the levels and quality ofsperm.[197]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.[198][194]
Cardiovascular health
TheFood and Drug Administration (FDA) granted the following health claim for soy: "25 grams of soy protein a day, as part of a diet low insaturated fat andcholesterol, may reduce the risk ofheart disease."[139] One serving, (1 cup or 240 mL) of soy milk, for instance, contains 6 or 7 grams of soy protein.
AnAmerican Heart Association (AHA) review of a decade long study of soy protein benefits did not recommendisoflavone supplementation. The review panel also found that soy isoflavones have not been shown to reduce post-menopausal "hot flashes" and the efficacy and safety of isoflavones to help prevent cancers of the breast, uterus or prostate is in question. AHA concluded that "many soy products should be beneficial to cardiovascular and overall health because of their high content ofpolyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat".[199] Other studies found that soy protein consumption could lower theconcentration oflow-density lipoproteins (LDL) transporting fats in the extracellular water tocells.[200][201]
Research by constituent
Lignans
Plantlignans 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 precursorsecoisolariciresinol containing 13–273 μg/100 g dry weight.[202]
Soybeans and processed soy foods are among the richest foods in totalphytoestrogens (wet basis per 100 g), which are present primarily in the form of theisoflavones,daidzein andgenistein.[155][203] Because most naturally occurring phytoestrogens act asselective 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.[204][205] The major product of daidzein microbial metabolism isequol.[206] Only 33% of Western Europeans have amicrobiome that produces equol, compared to 50–55% of Asians.[206]
Soy isoflavones—polyphenolic compounds that are also produced by other legumes like peanuts andchickpeas[155]—are under preliminary research. As of 2016, nocause-and-effect relationship has been shown inclinical research to indicate that soy isoflavones lower the risk of cardiovascular diseases.[155][199][207]
Phytic acid
Soybeans containphytic acid, which may act as achelating agent and inhibit mineral absorption, especially for diets already low in minerals.[208]
In culture
Although observations of soy consumption inducinggynecomastia on men[209] are not conclusive,[210] a pejorative term, "soy boy", has emerged to describe perceived emasculated young men withfeminine traits.[211]
Futures
Soybeanfutures are traded on theChicago Board of Trade and have delivery dates in January (F), March (H), May (K), July (N), August (Q), September (U), November (X).
They are also traded on other commodity futures exchanges under different contract specifications:
da Silva, Claiton Marcio; de Majo, Claudio, eds.The Age of the Soybean: An Environmental History of Soy during the Great Acceleration (White Horse Press, 2022)online review
^Hymowitz T (August 9, 1995). "Evaluation of Wild PerennialGlycine Species and Crosses For Resistance to Phakopsora". In Sinclair J, Hartman G (eds.).Proceedings of the Soybean Rust Workshop.Urbana, IL, US: National Soybean Research Laboratory. pp. 33–37.
^Heuzé V., Tran G., Giger-Reverdin S., Lebas F., 2015. Perennial soybean (Neonotonia wightii). Feedipedia, a programme byINRA,CIRAD, Association Française de Zootechnie andFAO.https://www.feedipedia.org/node/293 Last updated on September 30, 2015, 15:09
^Nataraj V, Maranna S, Kumawat G, et al. (2020). "Genetic inheritance and identification of germplasm sources for anthracnose resistance in soybean [Glycine max (L.) Merr.]".Genetic Resources and Crop Evolution.67 (6):1449–1456.Bibcode:2020GRCEv..67.1449N.doi:10.1007/s10722-020-00917-4.S2CID211730576.
^Concibido VC, Lange DA, Denny RL, et al. (1997). "Genome Mapping of Soybean Cyst Nematode Resistance Genes in 'Peking', PI 90763, and PI 88788 Using DNA Markers".Crop Science.37 (1):258–264.doi:10.2135/cropsci1997.0011183x003700010046x.
^Shurtleff, William; Aoyagi, Akiko. 2013. History of Whole Dry Soybeans, Used as Beans, or Ground, Mashed or Flaked (240 BCE to 2013). Lafayette, California. 950 pp.
^Shurtleff, W.; Aoyagi, A. 2015. "History of Soybeans and Soyfoods in Spain and Portugal (1603–2015)." Lafayette, California: Soyinfo Center. (624 references; 23 photos and illustrations. Free online.)
^Shurtleff, W.; Aoyagi, A. (2015).History of Soybeans and Soyfoods in Italy (1597–2015). Lafayette, California: Soyinfo Center. 618 pp. (1,381 references; 93 photos and illustrations. Free online.)
^Matagrin. 1939. "Le Soja et les Industries du Soja," p. 47–48
^Shurtleff, W.; Aoyagi, A. 2015. "History of Soybeans and Soyfoods in Greece, the European Union and Small Western European Countries (1939–2015)." Lafayette, California: Soyinfo Center. 243 pp. (462 references; 20 photos and illustrations. Free online.ISBN978-1-928914-81-5).
^Shurtleff, W.; Aoyagi, A.; 2015. "History of Soybeans and Soyfood in France (1665–2015)". Lafayette, California; Soyinfo Center. 1,202 pp. (3,405 references; 145 photos and illustrations. Free online).
^abShurtleff, W.; Aoyagi, A. 2015. "History of Soybeans and Soyfoods in Austria and Switzerland (1781–2015)." Lafayette, California: Soyinfo Center. 705 pp. (1444 references; 128 photos and illustrations). Free online.ISBN978-1-928914-77-8.
^Ofstehage AL (May 10, 2018). "Financialization of work, value, and social organization among transnational soy farmers in the Brazilian Cerrado".Economic Anthropology.5 (2):274–285.doi:10.1002/sea2.12123.ISSN2330-4847.
^Sneller CH (2003). "Impact of Transgenic Genotypes and Subdivision on Diversity Within Elite North American Soybean Germplasm".Crop Science.43:409–14.doi:10.2135/cropsci2003.0409.
^"EU Caught in Quandary Over GMO Animal Feed Imports".The Guardian. December 7, 2007.
^Cantani A, Lucenti P. (August 1997). "Natural History of Soy Allergy and/or Intolerance in Children, and Clinical Use of Soy-protein Formulas".Pediatric Journal of Allergy and Clinical Immunology.8 (2):59–74.doi:10.1111/j.1399-3038.1997.tb00146.x.PMID9617775.S2CID35264190.
^"Regulation (EG) 1169/2011". Eur-Lex - European Union Law, European Union. October 25, 2011. RetrievedOctober 7, 2020.
^Messina M, Redmond G (2006). "Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: A review of the relevant literature".Thyroid.16 (3):249–58.doi:10.1089/thy.2006.16.249.PMID16571087.
^Protein Quality Evaluation: Report of the Joint FAO/WHO Expert Consultation. Bethesda, MD: Food and Agriculture Organization of the United Nations (Food and Nutrition Paper No. 51). 1989.ISBN978-92-5-103097-4.
^abSeed Proteins; Peter R. Shewery and Rod Casey (Eds) 1999. Kluwer Academic Publishers, Dordrecht, The Netherlands
^Barringer S (February 3, 2010)."The Chemistry of Chocolate Flavor"(PDF).Ohio State University. Archived fromthe original(PDF) on March 24, 2012. RetrievedAugust 24, 2013.Two proteases: aspartic endopeptidase and serine carboxy-(exo)peptidase on vicilin (7S)-class globulin storage proteins.
^abcdefg"Soy isoflavones". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis. 2016. RetrievedMarch 4, 2021.
^Heuzé V., Thiollet H., Tran G., Lessire M., Lebas F., 2017. Soybean hulls. Feedipedia, a program by INRA, CIRAD, AFZ, and FAO.https://www.feedipedia.org/node/719
^Heuzé V., Tran G., Nozière P., Lessire M., Lebas F., 2017. Soybean seeds. Feedipedia, a program by INRA, CIRAD, AFZ, and FAO.https://www.feedipedia.org/node/42 Last updated on July 4, 2017, 10:37
^Mustakas GC, Griffin EL, Sohns VE (1966). "Full-Fat Soybean Flours by Continuous Extrusion Cooking".World Protein Resources. Advances in Chemistry. Vol. 57. pp. 101–11.doi:10.1021/ba-1966-0057.ch008.ISBN978-0-8412-0058-6.
^Giampietro P, Bruno G, Furcolo G, et al. (2004). "Soy Protein Formulas in Children: No Hormonal Effects in Long-term Feeding".Journal of Pediatric Endocrinology and Metabolism.17 (2):191–96.doi:10.1515/JPEM.2004.17.2.191.PMID15055353.S2CID43304969.
^Harland J, Haffner T (September 2008). "Systematic Review, Meta-analysis and Regression of Randomised Controlled Trials Reporting an Association Between an Intake of Circa 25 g Soya Protein Per Day and Blood Cholesterol".Atherosclerosis.200 (1):13–27.doi:10.1016/j.atherosclerosis.2008.04.006.PMID18534601.
^Mitchell JH, Cawood E, Kinniburgh D, et al. (June 2001). "Effect of a Phytoestrogen Food Supplement on Reproductive Health in Normal Males".Clinical Science.100 (6):613–18.doi:10.1042/CS20000212.PMID11352776.
^Reliance on the main genetic source of SCN resistance (PI 88788)may be helping SCN to overcome SCN-resistant varieties. Out of 807 resistant varieties listed by ISU this year, just 18 had a genetic background outside of PI 88788. "We have lots of varieties to pick from, but the genetic background is not as diverse as we would like it to be," says Tylka.
^There have been cases where SCN has clipped yields of SCN-resistant varieties. Reliance on the main genetic source of SCN resistance (PI 88788)may be helping SCN to overcome SCN-resistant varieties.
_Merr.%2c_1804.jpg)
