Soy protein
Encyclopedia
Soy protein is a protein
that is isolated from soybean
. It is made from dehulled
, defatted soybean meal
. Dehulled and defatted soybeans are processed into three kinds of high protein commercial products : soy flour, concentrates, and isolates. Soy protein isolate has been used since 1959 in foods for its functional properties. Recently, soy protein popularity has increased due to its use in health food products, and many countries allow health claims for foods that are rich in soy protein.
Soy protein is generally regarded as the storage protein held in discrete particles called protein bodies, which are estimated to contain at least 60–70% of the total soybean protein. Upon germination of the soybean, the protein will be digested, and the released amino acids will be transported to locations of seedling growth. Legume proteins, such as soy and pulses, belong to the globulin family of seed storage proteins called leguminins (11S Globulin Fraction) and vicilins (7S Globulin), or in the case of soybeans, glycinin and beta-conglycinin.[1][2] Grains contain a third type of storage protein called gluten or "prolamines." Soybeans also contain biologically active or metabolic proteins such as enzymes, trypsin inhibitors, hemagglutinins, and cysteine proteases very similar to papain. The soy cotyledon storage proteins, important for human nutrition, can be extracted most efficiently by water, water plus dilute alkali (pH 7–9), or aqueous solutions of sodium chloride (0.5–2 M) from dehulled and defatted soybeans that have undergone only a minimal heat treatment so that the protein is close to being native or undenatured.[3] Soybeans are processed into three kinds of modern protein-rich products: soy flour, soy concentrate, and soy isolate.
Soy protein contains phytoestrogens, which bind to estrogen receptors in the body. Studies on phytoestrogens suggest these compounds may decrease the risk of cancer
.
and Frank Calvert spun into an artificial silk that was then tailored into that now famous "silk is soy" suit that Henry Ford
wore on special occasions. The plant's eventual daily output of forty tons of soy protein isolate made the Soya Products Division into Glidden
's most profitable division.
At the start of the Second World War, Glidden sent a sample of Julian's isolated soy protein to National Foam System Inc. (today a unit of Kidde Fire Fighting
) which used it to develop Aero-Foam Aer-O-Foam, used by the U.S. Navy for fire fighting and referred to as "bean soup". While not exactly the brainchild of Dr. Julian, it was the meticulous care given to the preparation of the soy protein that made the fire fighting foam possible. When a hydrolyzate
of isolated soy protein was fed into a water stream, the mixture was converted into a foam by means of an aerating nozzle. The soy protein foam was used to smother oil and gasoline fires aboard ships, and was particularly useful on aircraft carriers. It saved the lives of thousands of sailors.
In 1958, Central Soya of Fort Wayne, Indiana acquired Julian's Soy Products Division (Chemurgy) of the Glidden Paint Company, Chicago. Recently, Central Soya's (Bunge) Protein Division, in January, 2003, joined/merged with DuPont's soy protein business (Solae), which in 1997 had acquired Ralston Purina's soy division, Protein Technologies International (PTI) in St. Louis. Eighth Continent, an "ersatz" soy milk, is a combined "venture" product of DuPont and General Mills.
Food-grade soy protein isolate first became available on October 2, 1959 with the dedication of Central Soya's edible soy isolate, Promine D, production facility on the Glidden Company industrial site in Chicago. An edible soy isolate and edible spun soy fiber have also been available since 1960 from the Ralston Purina Company in St. Louis, who had hired Boyer and Calvert. In 1987, PTI became the world's leading maker of isolated soy protein.
s, imitation meats
, beverage powders, cheese
s, non-dairy creamer
, frozen desserts, whipped topping
, infant formula
s, bread
s, breakfast cereal
s, pasta
s, and pet foods.
s, asphalt
s, resin
s, cleaning materials, cosmetics
, ink
s, pleather, paints
, paper coatings, pesticide
s/fungicide
s, plastic
s, polyester
s, and textile
fibres.
below 9. The extract is clarified to remove the insoluble material and the "supernatant" is acidified to a pH range of 4-5. The precipitated protein-curd is collected and separated from the whey by centrifuge
. The curd is usually neutralized with alkali
to form the sodium proteinate salt
before drying
Soy protein concentrate is produced by immobilizing the soy globulin proteins while allowing the soluble carbohydrates, soy whey proteins, and salts to be leached from the defatted flakes or flour
. The protein is retained by one or more of several treatments: leaching with 20-80% aqueous alcohol
/solvent
, leaching with aqueous acids in the isoelectric zone of minimum protein solubility, pH 4-5; leaching with chilled water (which may involve calcium or magnesium cations), and leaching with hot water of heat-treated defatted soy meal/flour.
All of these processes result in a product that is 70% protein
, 20% carbohydrates (2.7 to 5% crude fiber
), 6% ash
and about 1% oil, but the solubility may differ. One tonne
of defatted soybean flakes will yield about 750 kg of soybean protein concentrate.
s and carbohydrates removed. Because of this, it has a neutral flavor
and will cause less flatulence
due to bacterial fermentation.
Soy isolates are mainly used to improve the texture of meat products, but are also used to increase protein content, enhance moisture retention, and as an emulsifier. Flavor is affected, but whether it is an enhancement is subjective.
Before 2006, the U.S. Food and Drug Administration (FDA) was examining flavor reversion concerns related to levels of the toxin furan
in soy protein isolate and other foods. This problem has been solved by David Min of the Ohio Agricultural Research and Development Center. The chlorophyll in soy oil was reacting in the presence of light to form trans-2-heptenal and 2-
pentenylfuran . Chlorophyll in soy oil is now removed with diatomaceous earth filters.
Pure soy protein isolate is used mainly by the food industry
. It is sometimes available in health stores or in the pharmacy
section of the supermarket
. It is usually found combined with other food ingredient
s.
Soy protein concentrate retains most of the fiber of the original soybean. It is widely used as functional or nutritional ingredient in a wide variety of food products, mainly in baked foods, breakfast cereals, and in some meat products. Soy protein concentrate is used in meat and poultry products to increase water and fat retention and to improve nutritional values (more protein, less fat).
Soy protein concentrates are available in different forms: granules, flour
and spray-dried. Because they are very digestible, they are well-suited for children, pregnant and lactating women, and the elderly. They are also used in pet food
s, milk replacements for babies (human
and livestock
), and even used for some non-food applications.
s); defatted (oils removed) with 50% protein content and with either high water solubility or low water solubility; and lecithinated (lecithin
added). As soy flour is gluten
-free, yeast
-raised bread
s made with soy flour are dense in texture.
Soy grits are similar to soy flour except that the soybeans have been toasted and cracked into coarse pieces. Kinako
is a soy flour used in Japanese cuisine
.
" since it provides all of the essential amino acids for human nutrition. Soybean protein is essentially identical to that of other legume pulses
(that is to say, legume proteins in general consist of 7S and 11S storage proteins), and is one of the least expensive sources of dietary protein. For this reason, soy is important to many vegetarians
and vegans
.
Of any studied legume, whole soybeans have the highest levels of phytic acid
, an organic acid
and mineral chelator
present in many plant tissues, especially bran
and seed
s, which binds to certain ingested minerals: calcium, magnesium, iron, and especially zinc — in the intestinal tract, and reduces the amount the body assimilates. For people with a particularly low intake of essential minerals, especially young children and those in developing countries, this effect can be undesirable. However, dietary mineral chelators help prevent over-mineralization of joints, blood vessels, and other parts of the body, which is most common in older persons.
The digestibility of some soyfoods are as follows: steamed soybeans 65.3%, tofu 92.7%, soy milk 92.6%, soy protein isolate 93–97%. Some studies on rats have indicated that the biological value of soy protein isolates is comparable to animal proteins such as casein
if enriched with the sulfur-containing amino acid methionine.
Lafayette Mendel
and Morris S. Fine of the Sheffield Laboratory of Physiological Chemistry at Yale University
made the observation in the September 1911 edition of the Journal of Biological Chemistry
that soybeans produce a positive nitrogen (N) balance in a human subject when they conducted a study to determine the utilization of legume proteins. The treatment called for 5 days of a 2400 Calories (10,041,600 J) diet consisting of meat, eggs, nut butter, potatoes, and fruit, followed by six days where 90.5% of total nitrogen was supplied by soybeans, and then another 5 days of the first diet, minus the nut butter. They discovered that the soy bean nitrogen is "distinctly (if only slightly) less well utilized than that of the preceding and succeeding mixed diets".
When measuring the nutritional value of protein, the original Protein Efficiency Ratio
(PER) method, first proposed by Osborne and Mendel in 1917, was the most widely used method until 1990. This method was found to be flawed for the biological evaluation of protein quality because the young rats used in the study had higher relative requirements for sulfur-containing amino acids than did humans. As such, the analytical method that is universally recognized by the FAO/WHO (1990) as well as the U.S. Food and Drug Administration (FDA), United States Department of Agriculture
, United Nations University
(UNU) and the National Academy of Sciences
when judging the quality of protein is Protein Digestibility Corrected Amino Acid Score
, as it is viewed as accurately measuring the correct relative nutritional value of animal and vegetable sources of protein in the diet.
Based on this method, soy protein is considered to have a similar equivalent in protein quality to animal proteins. Egg white has a score of 1.00, beef 0.92, isolated soy protein 0.92, and soy concentrate 0.99. In 1990 at an FAO/WHO meeting, it was decided that proteins having values higher than 1.0 would be rounded or "leveled down" to 1.0 as scores above 1.0 are considered to indicate that the protein contains essential amino acids in excess of the human requirements.
scale. The Biological Value method, which dates back to 1911, relies on nitrogen retention as a measurement of protein quality. Soybean protein isolate has a biological value of 74. Whole soybean has a biological value of 96, and soy milk 91.
held in discrete particles called "protein bodies" estimated to contain at least 60% to 70% of the total protein within the soybean. This protein is important to the growth of new soyben plants, and when the soybean germinates
, the protein will be digested, and the released amino acids will be transported to locations of seedling growth. Legume proteins, such as soy and pulses, belong to the globulin
family of seed storage proteins called leguminins (11S Globulin Fraction) and vicilins (7S Globulin), or in the case of soybeans, glycinin and beta-conglycinin. Grains contain a third type of storage protein called gluten
or "prolamines."
Soybeans also contain biologically active or metabolic proteins such as enzymes, trypsin inhibitors, hemagglutinins, and cysteine proteases very similar to papain
. The soy cotyledon
storage proteins, important for human nutrition, can be extracted most efficiently by water, water plus dilute alkali (pH 7–9), or aqueous solutions of sodium chloride (0.5–2 M) from dehulled and defatted soybeans that have undergone only a minimal heat treatment so that the protein is close to being native or undenatured. Soybeans are processed into three kinds of modern protein-rich products: soy flour, soy concentrate, and soy isolate.
cholesterol
, low density lipoprotein
(LDL, bad) cholesterol and triglyceride concentrations. However, high density lipoprotein
(HDL, good) cholesterol did not increase. Soy phytoestrogens
(isoflavones: genistein
and daidzein
) adsorbed onto the soy protein were suggested as the agent reducing serum cholesterol levels. On the basis of this research, PTI, in 1998, filed a petition with FDA for a health claim that soy protein may reduce cholesterol and the risk of heart disease
.
The FDA granted this 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." One serving, (1 cup or 240 mL) of soy milk, for instance, contains 6 or 7 grams of soy protein.
In January 2006, an American Heart Association review (in the journal Circulation) of a decade-long study of soy protein benefits casts doubt on the FDA allowed "Heart Healthy" claim for soy protein. The panel also found that soy isoflavones do not reduce postmenopause "hot flashes" in women, nor do isoflavones help prevent cancers of the breast, uterus, or prostate. Thus, soy isoflavones in the form of supplements are not recommended. Among the conclusions, the authors state, "In contrast, soy products such as tofu, soy butter, soy nuts, or some soy burgers should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat. Using these and other soy foods to replace foods high in animal protein that contain saturated fat and cholesterol may confer benefits to cardiovascular health." -- Sacks et al. 113 (7): 1034—Circulation Article
The original paper is in the journal Circulation: January 17, 2006.
Soy is also rich in estrogenic compounds such as genistein
and daidzein
; however, research is conflicting as to whether or not it can cause increases in estrogen
in males.
A recent study by Goodin et al. found that 56g of soy protein powder per day caused serum testosterone to fall 4% in four weeks in a test group of twelve healthy males. (Note that there was an error in the abstract that said 19%, and this figure was erroneously reported by the media. The article reports 4% and not 19%.) According to the study, this data supports further studies of these hormonal effects as a mechanism in prostate cancer prevention. However, a study conducted by the Miami Research Associates refutes the finding of the Goodin study, finding that soy protein had no significant impact on testosterone levels in healthy males. In fact, only one participant in the Goodin study actually saw a drop in testosterone. The participant in question had testosterone levels 200% higher than all of the other subjects, and during the study, his levels dropped to bring him in line with the other participants. The Goodin study did not conclusively suggest that the participant's erratic testosterone levels were related to the soy protein.
It has been reported that lunasin, a soy peptide, reduces inflammation by reducing interleukin-6 and may help in leukemia
.
. The extrusion
technology
changes the structure of the soy protein, resulting in a fibrous spongy matrix that is similar in texture to meat.
While TSP has a shelf life
of more than a year when stored dry at room temperature
, it should be used at once or stored for no more than three days in the refrigerator
after rehydration. It is usually rehydrated with cold or hot water, but a bit of vinegar
or lemon juice
can be added to quicken the process. In the rehydration step of TSP, excess hot water is useful to leach out flatulence-producing carbohydrates.
Soy protein products such as TSP 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 and safely extending ground beef up to 30% for hamburgers, without reducing its nutritional value. Common alternative meat extenders are derivatives of fatty beef trimmings collectively called Advanced meat recovery
products. One such meat extender is ammonia
treated defatted beef trimmings, what the company, Beef Products
Inc, calls “lean finely textured beef”.
Rehydrated TSP flakes can also replace, at a minimum, 33% "tuna" fish in tuna salad. It is high in protein and low in fat and sodium.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that is isolated from soybean
Soybean
The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...
. It is made from dehulled
Husk
Husk in botany is the outer shell or coating of a seed. It often refers to the leafy outer covering of an ear of maize as it grows on the plant. Literally, a husk or hull includes the protective outer covering of a seed, fruit or vegetable...
, defatted soybean meal
Soybean meal
Soybean meal also known as Soyabean Oil Cake is a flour made by grinding the solid residue of soybean oil production. It is widely used as a filler and source of protein in animal diets, including pig, chicken, cattle, horse, sheep, and fish feed....
. Dehulled and defatted soybeans are processed into three kinds of high protein commercial products : soy flour, concentrates, and isolates. Soy protein isolate has been used since 1959 in foods for its functional properties. Recently, soy protein popularity has increased due to its use in health food products, and many countries allow health claims for foods that are rich in soy protein.
Soy protein is generally regarded as the storage protein held in discrete particles called protein bodies, which are estimated to contain at least 60–70% of the total soybean protein. Upon germination of the soybean, the protein will be digested, and the released amino acids will be transported to locations of seedling growth. Legume proteins, such as soy and pulses, belong to the globulin family of seed storage proteins called leguminins (11S Globulin Fraction) and vicilins (7S Globulin), or in the case of soybeans, glycinin and beta-conglycinin.[1][2] Grains contain a third type of storage protein called gluten or "prolamines." Soybeans also contain biologically active or metabolic proteins such as enzymes, trypsin inhibitors, hemagglutinins, and cysteine proteases very similar to papain. The soy cotyledon storage proteins, important for human nutrition, can be extracted most efficiently by water, water plus dilute alkali (pH 7–9), or aqueous solutions of sodium chloride (0.5–2 M) from dehulled and defatted soybeans that have undergone only a minimal heat treatment so that the protein is close to being native or undenatured.[3] Soybeans are processed into three kinds of modern protein-rich products: soy flour, soy concentrate, and soy isolate.
Soy protein contains phytoestrogens, which bind to estrogen receptors in the body. Studies on phytoestrogens suggest these compounds may decrease the risk of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
History
Soy protein has been available since 1936 for its functional properties. In that year, organic chemist Percy Lavon Julian designed the world's first plant for the isolation of industrial-grade soy protein. The largest use of industrial grade protein was, and still is, for paper coatings, in which it serves as a pigment binder. However, Dr. Julian's plant must have also been the source of the "soy protein isolate" which Ford's Robert BoyerRobert Boyer (chemist)
Robert Allen Boyer was a chemist employed by Henry Ford, he was extremely proficient at inventing ways to convert soybeans into paints and plastic parts used on Ford automobiles. -References:...
and Frank Calvert spun into an artificial silk that was then tailored into that now famous "silk is soy" suit that Henry Ford
Henry Ford
Henry Ford was an American industrialist, the founder of the Ford Motor Company, and sponsor of the development of the assembly line technique of mass production. His introduction of the Model T automobile revolutionized transportation and American industry...
wore on special occasions. The plant's eventual daily output of forty tons of soy protein isolate made the Soya Products Division into Glidden
Glidden (paints)
The Glidden Company was a paint company started in 1875 by Francis Harrington Glidden, Levi Brackett and Thomas Bolles. The company started in 1875 as the Glidden-Brackett Company; and was renamed later to the Glidden & Joy Company, and in 1890 incorporated as The Glidden Varnish Company. It is...
's most profitable division.
At the start of the Second World War, Glidden sent a sample of Julian's isolated soy protein to National Foam System Inc. (today a unit of Kidde Fire Fighting
Kidde
Kidde, a brand and division of United Technologies Corporation, is a business, or group of businesses, that manufactures and distributes fire detection and extinguishing equipment.-History:The company was founded by Walter Kidde in 1917 in the United States...
) which used it to develop Aero-Foam Aer-O-Foam, used by the U.S. Navy for fire fighting and referred to as "bean soup". While not exactly the brainchild of Dr. Julian, it was the meticulous care given to the preparation of the soy protein that made the fire fighting foam possible. When a hydrolyzate
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
of isolated soy protein was fed into a water stream, the mixture was converted into a foam by means of an aerating nozzle. The soy protein foam was used to smother oil and gasoline fires aboard ships, and was particularly useful on aircraft carriers. It saved the lives of thousands of sailors.
In 1958, Central Soya of Fort Wayne, Indiana acquired Julian's Soy Products Division (Chemurgy) of the Glidden Paint Company, Chicago. Recently, Central Soya's (Bunge) Protein Division, in January, 2003, joined/merged with DuPont's soy protein business (Solae), which in 1997 had acquired Ralston Purina's soy division, Protein Technologies International (PTI) in St. Louis. Eighth Continent, an "ersatz" soy milk, is a combined "venture" product of DuPont and General Mills.
Food-grade soy protein isolate first became available on October 2, 1959 with the dedication of Central Soya's edible soy isolate, Promine D, production facility on the Glidden Company industrial site in Chicago. An edible soy isolate and edible spun soy fiber have also been available since 1960 from the Ralston Purina Company in St. Louis, who had hired Boyer and Calvert. In 1987, PTI became the world's leading maker of isolated soy protein.
Food uses
Soy protein is used in a variety of foods such as salad dressings, soupSoup
Soup is a generally warm food that is made by combining ingredients such as meat and vegetables with stock, juice, water, or another liquid. Hot soups are additionally characterized by boiling solid ingredients in liquids in a pot until the flavors are extracted, forming a broth.Traditionally,...
s, imitation meats
Meat analogue
A meat analogue, also called a meat substitute, mock meat, faux meat, or imitation meat, approximates the aesthetic qualities and/or chemical characteristics of specific types of meat...
, beverage powders, cheese
Cheese
Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....
s, non-dairy creamer
Non-dairy creamer
Non-dairy creamers are liquid or granular substances intended to substitute for milk or cream as an additive to coffee or other beverages. They do not contain lactose and therefore are commonly described as not being dairy products...
, frozen desserts, whipped topping
Whipped topping
Whipped topping is imitation whipped cream. Like other ersatz products, there are various reasons for using an imitation:* To exclude dairy ingredients to avoid milk allergies.* To support food taboos such as veganism or kosher meat and milk rules....
, infant formula
Infant formula
Infant formula is a manufactured food designed and marketed for feeding to babies and infants under 12 months of age, usually prepared for bottle-feeding or cup-feeding from powder or liquid . The U.S...
s, bread
Bread
Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...
s, breakfast cereal
Breakfast cereal
A breakfast cereal is a food made from processed grains that is often, but not always, eaten with the first meal of the day. It is often eaten cold, usually mixed with milk , water, or yogurt, and sometimes fruit but sometimes eaten dry. Some cereals, such as oatmeal, may be served hot as porridge...
s, pasta
Pasta
Pasta is a staple food of traditional Italian cuisine, now of worldwide renown. It takes the form of unleavened dough, made in Italy, mostly of durum wheat , water and sometimes eggs. Pasta comes in a variety of different shapes that serve for both decoration and to act as a carrier for the...
s, and pet foods.
Functional uses
Soy protein is used for emulsification and texturizing. Specific applications include adhesiveAdhesive
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...
s, asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
s, resin
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
s, cleaning materials, cosmetics
Cosmetics
Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...
, ink
Soy ink
Soy ink is a kind of ink made from soybeans. As opposed to traditional petroleum-based ink, soy-based ink is more environmentally friendly, might provide more accurate colors, and makes it easier to recycle paper...
s, pleather, paints
Soy paint
Soy paint is paint made primarily from soy, it combines the advantage of being a renewable resource with the potential of non-toxic product.-Oil:...
, paper coatings, pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s/fungicide
Fungicide
Fungicides are chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality and profit. Fungicides are used both in agriculture and to fight fungal infections in animals...
s, plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
s, polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
s, and textile
Textile
A textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands...
fibres.
Production methods
Edible soy protein "isolate" is derived from defatted soy flour with a high solubility in water (high NSI). The aqueous extraction is carried out at a pHPH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
below 9. The extract is clarified to remove the insoluble material and the "supernatant" is acidified to a pH range of 4-5. The precipitated protein-curd is collected and separated from the whey by centrifuge
Centrifuge
A centrifuge is a piece of equipment, generally driven by an electric motor , that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis...
. The curd is usually neutralized with alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
to form the sodium proteinate salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
before drying
Soy protein concentrate is produced by immobilizing the soy globulin proteins while allowing the soluble carbohydrates, soy whey proteins, and salts to be leached from the defatted flakes or flour
Flour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...
. The protein is retained by one or more of several treatments: leaching with 20-80% aqueous alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
/solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
, leaching with aqueous acids in the isoelectric zone of minimum protein solubility, pH 4-5; leaching with chilled water (which may involve calcium or magnesium cations), and leaching with hot water of heat-treated defatted soy meal/flour.
All of these processes result in a product that is 70% protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
, 20% carbohydrates (2.7 to 5% crude fiber
Fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
), 6% ash
Ash (analytical chemistry)
In analytical chemistry, ashing is the process of mineralization for preconcentration of trace substances prior to chemical analysis. Ash is the name given to all non-aqueous residue that remains after a sample is burned, and consist mostly of metal oxides....
and about 1% oil, but the solubility may differ. One tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
of defatted soybean flakes will yield about 750 kg of soybean protein concentrate.
Isolates
Soy protein isolate is a highly refined or purified form of soy protein with a minimum protein content of 90% on a moisture-free basis. It is made from defatted soy flour which has had most of the non-protein components, fatFat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
s and carbohydrates removed. Because of this, it has a neutral flavor
Flavor
Flavor or flavour is the sensory impression of a food or other substance, and is determined mainly by the chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in the mouth and throat as well as temperature and texture, are also very important to the overall...
and will cause less flatulence
Flatulence
Flatulence is the expulsion through the rectum of a mixture of gases that are byproducts of the digestion process of mammals and other animals. The medical term for the mixture of gases is flatus, informally known as a fart, or simply gas...
due to bacterial fermentation.
Soy isolates are mainly used to improve the texture of meat products, but are also used to increase protein content, enhance moisture retention, and as an emulsifier. Flavor is affected, but whether it is an enhancement is subjective.
Before 2006, the U.S. Food and Drug Administration (FDA) was examining flavor reversion concerns related to levels of the toxin furan
Furan
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen. The class of compounds containing such rings are also referred to as furans....
in soy protein isolate and other foods. This problem has been solved by David Min of the Ohio Agricultural Research and Development Center. The chlorophyll in soy oil was reacting in the presence of light to form trans-2-heptenal and 2-
pentenylfuran . Chlorophyll in soy oil is now removed with diatomaceous earth filters.
Pure soy protein isolate is used mainly by the food industry
Food industry
The food production is a complex, global collective of diverse businesses that together supply much of the food energy consumed by the world population...
. It is sometimes available in health stores or in the pharmacy
Pharmacy
Pharmacy is the health profession that links the health sciences with the chemical sciences and it is charged with ensuring the safe and effective use of pharmaceutical drugs...
section of the supermarket
Supermarket
A supermarket, a form of grocery store, is a self-service store offering a wide variety of food and household merchandise, organized into departments...
. It is usually found combined with other food ingredient
Ingredient
An ingredient is a substance that forms part of a mixture . For example, in cooking, recipes specify which ingredients are used to prepare a specific dish. Many commercial products contain a secret ingredient that is purported to make them better than competing products...
s.
Concentrates
Soy protein concentrate is about 70% soy protein and is basically defatted soy flour without the water soluble carbohydrates. It is made by removing part of the carbohydrates (soluble sugars) from dehulled and defatted soybeans.Soy protein concentrate retains most of the fiber of the original soybean. It is widely used as functional or nutritional ingredient in a wide variety of food products, mainly in baked foods, breakfast cereals, and in some meat products. Soy protein concentrate is used in meat and poultry products to increase water and fat retention and to improve nutritional values (more protein, less fat).
Soy protein concentrates are available in different forms: granules, flour
Flour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...
and spray-dried. Because they are very digestible, they are well-suited for children, pregnant and lactating women, and the elderly. They are also used in pet food
Pet food
Pet food is plant or animal material intended for consumption by pets. Typically sold in pet stores and supermarkets, it is usually specific to the type of animal, such as dog food or cat food...
s, milk replacements for babies (human
Human
Humans are the only living species in the Homo genus...
and livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
), and even used for some non-food applications.
Flours
Soy flour is made by grinding soybeans into a fine powder. It comes in three forms: natural or full-fat (contains natural oilOil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
s); defatted (oils removed) with 50% protein content and with either high water solubility or low water solubility; and lecithinated (lecithin
Lecithin
Lecithin is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues, and in egg yolk, composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids .The word lecithin was originally coined in 1847 by...
added). As soy flour is gluten
Gluten
Gluten is a protein composite found in foods processed from wheat and related grain species, including barley and rye...
-free, yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
-raised bread
Bread
Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...
s made with soy flour are dense in texture.
Soy grits are similar to soy flour except that the soybeans have been toasted and cracked into coarse pieces. Kinako
Kinako
, also known as soybean flour, is a product commonly used in Japanese cuisine. Kinako is produced by finely grinding roasted soybeans into powder.Kinako, being composed of soybeans, is a healthy topping and flavoring which contains B vitamins and protein....
is a soy flour used in Japanese cuisine
Japanese cuisine
Japanese cuisine has developed over the centuries as a result of many political and social changes throughout Japan. The cuisine eventually changed with the advent of the Medieval age which ushered in a shedding of elitism with the age of shogun rule...
.
Nutrition
Soybean protein is a "complete proteinComplete protein
A complete protein is a source of protein that contains an adequate proportion of all nine of the essential amino acids necessary for the dietary needs of humans or other animals...
" since it provides all of the essential amino acids for human nutrition. Soybean protein is essentially identical to that of other legume pulses
Pulse (legume)
A pulse is an annual leguminous crop yielding from one to twelve seeds of variable size, shape, and color within a pod. Pulses are used for food and animal feed. The term "pulse", as used by the Food and Agricultural Organization , is reserved for crops harvested solely for the dry seed...
(that is to say, legume proteins in general consist of 7S and 11S storage proteins), and is one of the least expensive sources of dietary protein. For this reason, soy is important to many vegetarians
Vegetarianism
Vegetarianism encompasses the practice of following plant-based diets , with or without the inclusion of dairy products or eggs, and with the exclusion of meat...
and vegans
Veganism
Veganism is the practice of eliminating the use of animal products. Ethical vegans reject the commodity status of animals and the use of animal products for any purpose, while dietary vegans or strict vegetarians eliminate them from their diet only...
.
Of any studied legume, whole soybeans have the highest levels of phytic acid
Phytic acid
Phytic acid is the principal storage form of phosphorus in many plant tissues, especially bran and seeds. Phytate is not digestible to humans or nonruminant animals, however, so it is not a source of either inositol or phosphate if eaten directly...
, an organic acid
Organic acid
An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are relatively stronger acids. The relative stability of the conjugate...
and mineral chelator
Chelation
Chelation is the formation or presence of two or more separate coordinate bonds between apolydentate ligand and a single central atom....
present in many plant tissues, especially bran
Bran
Bran is the hard outer layer of grain and consists of combined aleurone and pericarp. Along with germ, it is an integral part of whole grains, and is often produced as a by-product of milling in the production of refined grains. When bran is removed from grains, the grains lose a portion of their...
and seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s, which binds to certain ingested minerals: calcium, magnesium, iron, and especially zinc — in the intestinal tract, and reduces the amount the body assimilates. For people with a particularly low intake of essential minerals, especially young children and those in developing countries, this effect can be undesirable. However, dietary mineral chelators help prevent over-mineralization of joints, blood vessels, and other parts of the body, which is most common in older persons.
The digestibility of some soyfoods are as follows: steamed soybeans 65.3%, tofu 92.7%, soy milk 92.6%, soy protein isolate 93–97%. Some studies on rats have indicated that the biological value of soy protein isolates is comparable to animal proteins such as casein
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....
if enriched with the sulfur-containing amino acid methionine.
Lafayette Mendel
Lafayette Mendel
Lafayette Benedict Mendel was an American biochemist known for his work in nutrition including the study of Vitamin A, Vitamin B, lysine and tryptophan....
and Morris S. Fine of the Sheffield Laboratory of Physiological Chemistry at Yale University
Yale University
Yale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...
made the observation in the September 1911 edition of the Journal of Biological Chemistry
Journal of Biological Chemistry
The Journal of Biological Chemistry is a weekly peer-reviewed scientific journal that was established in 1905. Since 1925 it is published by the American Society for Biochemistry and Molecular Biology. It covers research in any area of biochemistry or molecular biology. The editor-in-chief is...
that soybeans produce a positive nitrogen (N) balance in a human subject when they conducted a study to determine the utilization of legume proteins. The treatment called for 5 days of a 2400 Calories (10,041,600 J) diet consisting of meat, eggs, nut butter, potatoes, and fruit, followed by six days where 90.5% of total nitrogen was supplied by soybeans, and then another 5 days of the first diet, minus the nut butter. They discovered that the soy bean nitrogen is "distinctly (if only slightly) less well utilized than that of the preceding and succeeding mixed diets".
When measuring the nutritional value of protein, the original Protein Efficiency Ratio
Protein efficiency ratio
Protein efficiency ratio is based on the weight gain of a test subject divided by its intake of a particular food protein during the test period....
(PER) method, first proposed by Osborne and Mendel in 1917, was the most widely used method until 1990. This method was found to be flawed for the biological evaluation of protein quality because the young rats used in the study had higher relative requirements for sulfur-containing amino acids than did humans. As such, the analytical method that is universally recognized by the FAO/WHO (1990) as well as the U.S. Food and Drug Administration (FDA), United States Department of Agriculture
United States Department of Agriculture
The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...
, United Nations University
United Nations University
The United Nations University is an academic arm of the United Nations established in 1973, which serves purposes and principles of the Charter of the United Nations. The UNU undertakes research into the pressing global problems of human survival, development and welfare that are the concern of...
(UNU) and the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
when judging the quality of protein is Protein Digestibility Corrected Amino Acid Score
PDCAAS
Protein Digestibility Corrected Amino Acid Score is a method of evaluating the protein quality based on both the amino acid requirements of humans and their ability to digest it...
, as it is viewed as accurately measuring the correct relative nutritional value of animal and vegetable sources of protein in the diet.
Based on this method, soy protein is considered to have a similar equivalent in protein quality to animal proteins. Egg white has a score of 1.00, beef 0.92, isolated soy protein 0.92, and soy concentrate 0.99. In 1990 at an FAO/WHO meeting, it was decided that proteins having values higher than 1.0 would be rounded or "leveled down" to 1.0 as scores above 1.0 are considered to indicate that the protein contains essential amino acids in excess of the human requirements.
Biological value of soy protein
Another measure of a protein's use in nutrition is the Biological ValueBiological Value
Biological value is a measure of the proportion of absorbed protein from a food which becomes incorporated into the proteins of the organism's body. It summarises how readily the broken down protein can be used in protein synthesis in the cells of the organism. Proteins are the major source of...
scale. The Biological Value method, which dates back to 1911, relies on nitrogen retention as a measurement of protein quality. Soybean protein isolate has a biological value of 74. Whole soybean has a biological value of 96, and soy milk 91.
Role in the growth of the soybean plant
Soy protein is generally regarded as stored proteinProtein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
held in discrete particles called "protein bodies" estimated to contain at least 60% to 70% of the total protein within the soybean. This protein is important to the growth of new soyben plants, and when the soybean germinates
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
, the protein will be digested, and the released amino acids will be transported to locations of seedling growth. Legume proteins, such as soy and pulses, belong to the globulin
Globulin
Globulin is one of the three types of serum proteins, the others being albumin and fibrinogen. Some globulins are produced in the liver, while others are made by the immune system. The term globulin encompasses a heterogeneous group of proteins with typical high molecular weight, and both...
family of seed storage proteins called leguminins (11S Globulin Fraction) and vicilins (7S Globulin), or in the case of soybeans, glycinin and beta-conglycinin. Grains contain a third type of storage protein called gluten
Gluten
Gluten is a protein composite found in foods processed from wheat and related grain species, including barley and rye...
or "prolamines."
Soybeans also contain biologically active or metabolic proteins such as enzymes, trypsin inhibitors, hemagglutinins, and cysteine proteases very similar to papain
Papain
Papain, also known as papaya proteinase I, is a cysteine protease enzyme present in papaya and mountain papaya .-Papain family:...
. The soy cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
storage proteins, important for human nutrition, can be extracted most efficiently by water, water plus dilute alkali (pH 7–9), or aqueous solutions of sodium chloride (0.5–2 M) from dehulled and defatted soybeans that have undergone only a minimal heat treatment so that the protein is close to being native or undenatured. Soybeans are processed into three kinds of modern protein-rich products: soy flour, soy concentrate, and soy isolate.
Health
In 1995, the New England Journal of Medicine (Vol. 333, No. 5) published a report from the University of Kentucky entitled, "Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids." It was financed by the PTI division of DuPont, The Solae Company, St. Louis. This meta-analysis concluded that soy protein is correlated with significant decreases in serumBlood serum
In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...
cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
, low density lipoprotein
Low density lipoprotein
Low-density lipoprotein is one of the five major groups of lipoproteins, which in order of size, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, that enable transport of cholesterol within the water-based bloodstream...
(LDL, bad) cholesterol and triglyceride concentrations. However, high density lipoprotein
High density lipoprotein
High-density lipoprotein is one of the five major groups of lipoproteins, which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, which enable lipids like cholesterol and triglycerides to be transported within the water-based bloodstream...
(HDL, good) cholesterol did not increase. Soy phytoestrogens
Phytoestrogens
Phytoestrogens are plant-derived xenoestrogens functioning as the primary female sex hormone not generated within the endocrine system but consumed by eating phytoestrogonic plants...
(isoflavones: genistein
Genistein
Genistein is one of several known isoflavones. Isoflavones, such as genistein and daidzein, are found in a number of plants including lupin, fava beans, soybeans, kudzu, and psoralea being the primary food source, also in the medicinal plant, Flemingia vestita and coffee Besides functioning as...
and daidzein
Daidzein
Daidzein belongs to the group of isoflavones. Daidzein and other isoflavone compounds, such as genistein, are present in a number of plants and herbs like the Thai Kwao Krua or Pueraria mirifica, Kudzu or Pueraria lobata, and in food sources such as soybeans and soy products like tofu and textured...
) adsorbed onto the soy protein were suggested as the agent reducing serum cholesterol levels. On the basis of this research, PTI, in 1998, filed a petition with FDA for a health claim that soy protein may reduce cholesterol and the risk of heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
.
The FDA granted this 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." One serving, (1 cup or 240 mL) of soy milk, for instance, contains 6 or 7 grams of soy protein.
In January 2006, an American Heart Association review (in the journal Circulation) of a decade-long study of soy protein benefits casts doubt on the FDA allowed "Heart Healthy" claim for soy protein. The panel also found that soy isoflavones do not reduce postmenopause "hot flashes" in women, nor do isoflavones help prevent cancers of the breast, uterus, or prostate. Thus, soy isoflavones in the form of supplements are not recommended. Among the conclusions, the authors state, "In contrast, soy products such as tofu, soy butter, soy nuts, or some soy burgers should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat. Using these and other soy foods to replace foods high in animal protein that contain saturated fat and cholesterol may confer benefits to cardiovascular health." -- Sacks et al. 113 (7): 1034—Circulation Article
The original paper is in the journal Circulation: January 17, 2006.
Soy is also rich in estrogenic compounds such as genistein
Genistein
Genistein is one of several known isoflavones. Isoflavones, such as genistein and daidzein, are found in a number of plants including lupin, fava beans, soybeans, kudzu, and psoralea being the primary food source, also in the medicinal plant, Flemingia vestita and coffee Besides functioning as...
and daidzein
Daidzein
Daidzein belongs to the group of isoflavones. Daidzein and other isoflavone compounds, such as genistein, are present in a number of plants and herbs like the Thai Kwao Krua or Pueraria mirifica, Kudzu or Pueraria lobata, and in food sources such as soybeans and soy products like tofu and textured...
; however, research is conflicting as to whether or not it can cause increases in estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
in males.
A recent study by Goodin et al. found that 56g of soy protein powder per day caused serum testosterone to fall 4% in four weeks in a test group of twelve healthy males. (Note that there was an error in the abstract that said 19%, and this figure was erroneously reported by the media. The article reports 4% and not 19%.) According to the study, this data supports further studies of these hormonal effects as a mechanism in prostate cancer prevention. However, a study conducted by the Miami Research Associates refutes the finding of the Goodin study, finding that soy protein had no significant impact on testosterone levels in healthy males. In fact, only one participant in the Goodin study actually saw a drop in testosterone. The participant in question had testosterone levels 200% higher than all of the other subjects, and during the study, his levels dropped to bring him in line with the other participants. The Goodin study did not conclusively suggest that the participant's erratic testosterone levels were related to the soy protein.
It has been reported that lunasin, a soy peptide, reduces inflammation by reducing interleukin-6 and may help in leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
.
Textured Soy Protein
TSP is made by forming a dough from high nitrogen solubility index (NSI) defatted soy flour with water in a screw-type extruder and heating with or without steam. The dough is extruded through a die into various possible shapes: granules, flakes, chunks, goulash, steakettes (schnitzel), etc., and dried in an oven. TSP made from soy flour contains 50% soy protein and needs to be rehydrated before use at a weight ratio of 1 TSP:2 water. However, TSP, when made from soy concentrate, contains 70% protein and can be rehydrated at a ratio of 1:3. It can be used as a meat replacement or supplementDietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
. The extrusion
Extrusion
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...
technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
changes the structure of the soy protein, resulting in a fibrous spongy matrix that is similar in texture to meat.
While TSP has a shelf life
Shelf life
Shelf life is the length of time that food, drink, medicine, chemicals, and many other perishable items are given before they are considered unsuitable for sale, use, or consumption...
of more than a year when stored dry at room temperature
Room temperature
-Comfort levels:The American Society of Heating, Refrigerating and Air-Conditioning Engineers has listings for suggested temperatures and air flow rates in different types of buildings and different environmental circumstances. For example, a single office in a building has an occupancy ratio per...
, it should be used at once or stored for no more than three days in the refrigerator
Refrigerator
A refrigerator is a common household appliance that consists of a thermally insulated compartment and a heat pump that transfers heat from the inside of the fridge to its external environment so that the inside of the fridge is cooled to a temperature below the ambient temperature of the room...
after rehydration. It is usually rehydrated with cold or hot water, but a bit of vinegar
Vinegar
Vinegar is a liquid substance consisting mainly of acetic acid and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. Commercial vinegar is produced either by fast or slow fermentation processes. Slow methods generally are used with traditional...
or lemon juice
Lemon juice
The lemon fruit, from a citrus plant, provides a useful liquid when squeezed. Lemon juice, either in natural strength or concentrated, is sold as a bottled product, usually with the addition of preservatives and a small amount of lemon oil.-Uses:...
can be added to quicken the process. In the rehydration step of TSP, excess hot water is useful to leach out flatulence-producing carbohydrates.
Soy protein products such as TSP 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
Textured vegetable protein
Textured or texturized vegetable protein , also known as textured soy protein , soy meat, or soya meat is a meat analogue or meat extender made from defatted soy flour, a by-product of extracting soybean oil...
has been used for more than 50 years as a way of inexpensively and safely extending ground beef up to 30% for hamburgers, without reducing its nutritional value. Common alternative meat extenders are derivatives of fatty beef trimmings collectively called Advanced meat recovery
Advanced meat recovery
Advanced meat recovery is a slaughterhouse process by which the last traces ofusable meat are removed from bones and other carcass materials after the primal cuts have been carved off manually....
products. One such meat extender is ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
treated defatted beef trimmings, what the company, Beef Products
Beef Products
Beef Products Inc. of Dakota Dunes, South Dakota, is a processor of beef trimmings. The company uses a patented process to enhance the pH in beef trimmings with ammonia that reduces the incidence of E. coli in downstream products...
Inc, calls “lean finely textured beef”.
Rehydrated TSP flakes can also replace, at a minimum, 33% "tuna" fish in tuna salad. It is high in protein and low in fat and sodium.
See also
- Edible protein per unit area of landEdible protein per unit area of landEdible protein per unit area of land is a measure of agricultural productivity. This measure for various major foodstuffs is shown in the chart below. Values are expressed for one calendar year. Biological values and usable protein values have been added to the chart to show the true relative value...
- SoybeanSoybeanThe soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...
s - Soy milkSoy milkSoy milk and sometimes referred to as soy drink/beverage is a beverage made from soybeans. A stable emulsion of oil, water, and protein, it is produced by soaking dry soybeans and grinding them with water...
- Textured soy protein
- Soy allergySoy allergySoy allergy is a type of food allergy. It is a hypersensitivity to dietary substances from soy causing an overreaction of the immune system which may lead to severe physical symptoms for millions of people. The Asthma and Allergy Foundation of America estimates soy is among the nine most common...