starch

1. A naturally abundant nutrient carbohydrate, (C₆H₁₀O₅)_n, found chiefly in the seeds, fruits, tubers, roots, and stem pith of plants, notably in corn, potatoes, wheat, and rice, and varying widely in appearance according to source but commonly prepared as a white amorphous tasteless powder.
2. Any of various substances, such as natural starch, used to stiffen cloth, as in laundering.
3. starches Foods having a high content of starch, as rice, breads, and potatoes.
4. 1. Stiff behavior.
   2. Vigor; mettle: "Business travel can take the starch out of the most self-assured corporate titan" (Lisa Faye Kaplan).

[Middle English starche, substance used to stiffen cloth (sense uncertain), from sterchen, to stiffen, from Old English *stercan.]

For more information on starch, visit Britannica.com.

A carbohydrate that occurs as discrete, partially crystalline granules in the seeds, roots (tubers), stems (pith), leaves, fruits, and pollen grains of higher plants. Starch functions as the main storage or reserve form of carbohydrate; it is second in abundance only to cellulose, a major structural component of plants. Cereal grains, tuber and root crops, and legumes (seeds) have long been used as major sources of carbohydrate in human diets. See also Cellulose.

Starch is isolated commercially from the following sources: cereal grain seeds [maize (corn), wheat, rice, sorghum], roots and tubers [potato, sweet potato, tapioca (cassava), arrowroot], and stems and pith (sago). Cereal grains are often steeped first to loosen the starch granules in the endosperm matrix, followed by wet grinding or milling. Roots and tubers are ground to give a suspension containing starch granules. Then follows screening or sieving, washing, centrifuging, dewatering, and drying.

Starch, a polymer of glucose, is an alpha-glucan, predominantly containing alpha-1,4-glucosidic linkages with a relatively small amount of alpha-1,6-glucosidic linkages forming branch points. Two major polymeric components are present: amylose and amylopectin. Normally a white powder of 98–99.5% purity, starch is insoluble in cold water, ethanol, and most common solvents. See also Glucose.

Starches are involved in important roles in foods, either naturally occurring in an ingredient or added to achieve a desired functional characteristic. Often the desired functional characteristic (thickening; gelling; adhesive; binding; improving acid, heat, and shear stability) cannot be achieved by using a native starch. Starches may be altered physically, chemically, or enzymatically to produce modified starches with improved functional properties.

The paper, textile, adhesive, chemical, pharmaceutical, and polymer industries use starch and starch derivatives. Organic acids and organic solvents for use as chemical intermediates, enzymes, hormones, antibiotics, and vaccines are industrially produced from starch. See also Carbohydrate.

Polysaccharide, a polymer of glucose units; the form in which carbohydrate is stored in the plant; it does not occur in animal tissue. (Glycogen is sometimes referred to as animal starch.) Starch is broken down by acid or enzymic hydrolysis (amylase), or during digestion, first to maltose and then glucose; it is the principal carbohydrate of the diet and hence the major source of energy. Starches from different sources (e.g. potato, maize, cereal, arrowroot, sago, etc.) have different structures, and contain different proportions of two major forms: amylose, which is a linear polymer and amylopectin, which has a branched structure. The mixture of dietary starches consists of about one-quarter amylose and three-quarters amylopectin.

A complex carbohydrate (polysaccharide) made of many glucose units. Uncooked starch is very difficult to digest, but heat opens out starch molecules so that they form a gel-like structure which is more accessible to digestive enzymes. During digestion, enzymes in the gut help to break down the starch into dextrins, and then glucose molecules which are absorbed into the blood. Starch takes much longer to digest than simple sugars, such as sucrose (table sugar). Consequently, starch provides a steady stream of glucose into the bloodstream and is less likely than sucrose to cause blood glucose swings which can provoke the secretion of excess insulin.

High quantities of starch are found in bananas which are still green at their tips (in brown bananas, most of the starch is converted to sugars), breads, corn, oats, pasta, potatoes, rice, and yams. Unrefined forms of these foods also contain other nutrients, especially vitamins, trace minerals, and fibre. They are a much better source of carbohydrates than manufactured, sweet products containing little other than sugar. For example, wholemeal pasta contains high levels of carbohydrate and significant amounts of dietary fibre, minerals, and B complex vitamins. This makes it a favourite pre-race food for many marathon runners: the carbohydrate helps to boost muscle glycogen stores, and the other components help to maintain the health and efficiency of the runner. See also resistant starch.

noun

A quality of active mental and physical forcefulness: dash, punch, verve, vigor, vigorousness, vim, vitality. Informal snap. Idioms: vim and vigor. See action/inaction, tired/fresh.

verb

To make stiff or stiffer: stiffen. See flexible/rigid.

The principal molecule used for the storage of food in plants. Starch is a polysaccharide and is composed of long chains of glucose subunits.

A carbohydrate that acts as a storage product of plants. It is a polysaccharride made of alpha glucose units, forming amylose and amylopectin polymers. Uncooked starch is generally difficult to digest, but those starches with relatively high amounts of amylopectin are easier to digest and absorb than those with relatively high amounts of amylose. Cooked starches are easier to digest because heat breaks down starch molecules to smaller compounds called dextrins.

Starch is a highly organized mixture of two carbohydrate polymers, amylose and amylopectin, which are synthesized by plant enzymes and simultaneously packed into dense water-insoluble granules. Starch granules vary in size (1 to 100 microns [μ m] in diameter) and shape, which are characteristic of their specific plant origin. Starch is the major energy reserve for plants; it is located mainly in the seeds, roots or tubers, stem pith, and fruit. Starch amylose is primarily a linear chain of glucose units. Amylose chains can coil into double helices and become insoluble in cold water. Amylopectin also is composed of chains of glucose units, but the chains are branched. This branched structure renders amylopectin soluble in cold water. The molecular architecture of the amylopectin and amylose within the granules is not entirely understood, but the granules are insoluble in cold water. The functional properties of native starch are determined by the granule structure. Both the appearance of the granules and their functional properties vary with the plant source.

Physical and Functional Properties

In home cooking and in commercial food processing native starches are used for their thickening properties. Starch granules when heated in water gradually absorb water and swell in size, causing the mixture to thicken. With continued heating however, the swollen granules fragment, the mixture becomes less thick, and the amylose and amylopectin become soluble in the hot mixture. This process of granule swelling and fragmenting is called gelatinization. Once gelatinized the granules cannot be recreated and the starch merely behaves as a mixture of amylose and amylopectin. Because of the larger size of the swollen granules compared to the size of amylose and amylopectin, the viscosity of the swollen granule mixture is much higher than the viscosity (the resistance to flow or a liquid or semi-liquid mixture) of the amylose/amylopectin mixture. Starches from different plant sources vary in their gelatinization temperatures, rate of gelatinization, maximum viscosity, clarity of the gelatinized mixture, and ability to form a solid gel on cooling.

The texture of heat-gelatinized starch mixtures is variable. Some gelatinized starch mixtures have a smooth creamy texture, while others are more pastelike. Some starches form gels after cooking and cooling. These starch gels may lack stability and slowly exude water through the gel surface. A similar breakdown of the gelatinized starch occurs in some frozen foods during thawing and refreezing. Although amylose is soluble in the hot gelatinized starch mixture, it tends to become insoluble in the cooled mixture. This phenomenon is called retrogradation and it occurs when the amylose chains bind together in helical and double helical coils. Retrogradation affects the texture of the food product and it also lowers the digestibility of the product. The proper starches must be employed for the different food products to minimize these problems. Certain starches are good film formers and can be used in coatings or as film barriers for protection of the food from oil absorption during frying.

Native and Modified Starches

The predominant commercial starches are those from field corn (maize), potato, cassava (tapioca), wheat, rice, and arrowroot. Field cornstarch (27 percent amylose and 73 percent amylopectin) is the major commercial starch worldwide. Genetic variants of field corn include waxy maize, which produces a starch with 98 to 100 percent amylopectin, and high-amylose starches, which have amylose contents of 55 percent, 70 percent, and higher. Waxy starch does not form gels and does not retrograde readily. High-amylose starches retrograde more extensively than normal starches and are less digestible. Their linear structure enables them to form films.

From the 1940s on the demand for convenience foods, dry mixes, and various processed foods has led to the modification of starches for food use and for other commercial products. These modified starches improve the textural properties of food products and may be more suitable for use in modern processing equipment. The Food and Drug Administration regulates use of the various modified food starches by stipulating the types of modification allowed, the degree of modification, and the reagents used in chemical modification. However, the food label is required only to state that "modified starch" is present. Only a small fraction of the sites available for modification of the food starches are actually modified. Although the degree of modification is small, the properties of the starches are significantly improved. This small degree of modification is sufficient to give a more soluble and stable starch after cooking. The clarity of the gelatinized starch as well as the stability of the cooked starch and starch gels are improved. The modification procedures are carried out under mild conditions that do not cause gelatinization of the native starch granules, and therefore the functional properties of the granule are preserved. The emulsifying properties of starch also may be improved by proper modification, improving the stability of salad dressings and certain beverages.

Physically modified starches include a pregelatinized starch that is prepared by heat-gelatinization and then dried to a powder. This instant starch is water-soluble and doesn't require further cooking. Because of its lower viscosity resulting from loss of granule structure, the starch can be used at higher concentrations. Certain confectionaries require high levels of starch to give structure to their products. These gelatinized instant starches serve this role. Cold water swelling starches represent a different type of instant starch. They are made by a proprietary process that retains the granule structure but lowers the granule strength. These cold water swelling starches give higher viscosities than the other instant starches. They are used in instant food mixes and for products such as low-fat salad dressings and mayonnaise.

Plant breeding has led to specialty starches with atypical proportions of amylose and amylopectin. Waxy maize starch with nearly 100 percent amylopectin is inherently stable to retrogradation. Chemically cross-linked waxy maize starch is a very high-quality modified starch. High-amylose starches have become available more recently and have led to lower caloric starches. Because of the crystallinity of these starches they are partially resistant to digestion by intestinal amylases and behave as dietary fiber when analyzed by the official methods of analysis for dietary fiber. Some of these high-amylose starches contain as high as 60 percent dietary fiber when analyzed.

The nutritional value of uncooked (ungelatinized) starchy foods (cereal grains, potato, peas, and beans) is relatively poor. Our digestive enzymes do not readily convert the native granular starch of uncooked fruits and vegetables into glucose that would be absorbed in the small intestine. Undigested starch passes into the large intestine where, along with dietary fiber, it is broken down to glucose and fermented to short-chain fatty acids. Some of these short-chain acids are absorbed from the large intestine resulting in recovery of some of the caloric value of the native starch.

Starch-Derived Dextrins and Corn Syrups

Modified starches as described above were developed to improve starch functionality in foods as well as their ability to withstand the physical forces of modern food processing systems. In addition to the food applications of starches and modified starches, the native starches are also converted into other products that serve food and other industries. These products do not require the granular character of native starches, which is lost by chemical or enzymic action during processing of the starch.

Dextrinization, a process requiring high temperatures and acid that has been in use since the early 1800s, converts native starch into dextrins that are composed of amylose and amylopectin chains of smaller sizes and altered structure. Consequently, food and nonfood industries have access to a range of dextrins of varying molecular sizes, solubility, and viscosity, but without the granular characteristics described above. Corn syrups are made in the same way as the dextrins, but they are converted to a higher degree such that glucose is a major ingredient. The more recent availability of an enzyme that converts glucose into fructose has led to a new industry in high-fructose corn syrups, which have found a strong market in beverages.

Bibliography

Frazier, Peter J., Peter Richmond, and Athene M. Donald, eds. Starch Structure and Functionality. Cambridge, U.K.: Royal Society of Chemistry, 1997.

Light, Joseph M. "Modified Food Starches: Why, What, Where, and How." Cereal Foods World 35 (1990): 1081–1092.

Murphy, Pauline. "Starch." In Handbook of Hydrocolloids, edited by Glyn O. Phillips and Peter A. Williams. Cambridge, U.K.: Woodhead Publishing; Boca Raton, Fla.: CRC Press LLC, 2000.

Thomas, David J., and William A. Atwell. Starches. St. Paul, Minn.: Eagan Press, 1999.

—Betty A. Lewis

1. any of a group of polysaccharides of the general formula, (C₆H₁₀O₅)_n; it is the chief storage form of carbohydrates in plants.
2. granular material separated from mature grain of Zea mays (Indian corn, or maize); used as a dusting powder and tablet disintegrant in pharmaceuticals.

• s. blockers — inhibitors of alpha-amylase, used to decrease starch digestion and limit energy intake from starch.
• s. digestion test, s. tolerance test — a test to assess the ability of the intestine to digest and absorb a polysaccharide. Efficiency measured by the rise in blood glucose after oral administration of starch to an animal that has been fasted.
• s. equivalent — an outmoded way of estimating and expressing the energy value of a feed. Replaced now by metabolizable energy.
• s. inhalation — can occur in pigs in a poorly ventilated environment and when the feed is fed dry. Causes foreign body pneumonia.
• s.–iodine complex — is a deep blue color and this is used as an indicator of the amount of starch in a solution.
• s. tolerance test — see starch digestion test (above).

Starch
Identifiers
CAS number	9005-25-8 Y
EC-number	232-679-6
RTECS number	GM5090000
Properties
Molecular formula	(C6H10O5)n
Appearance	white powder
Density	1.5 g/cm3
Melting point	decomp.
Solubility in water	none
Hazards
MSDS	ICSC 1553
EU Index	not listed
Autoignition temperature	410 ºC
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Structure of the amylose molecule.

Structure of the amylopectin molecule.

Granules of wheat starch, stained with iodine, photographed through a light microscope.

Starch or amylum is a polysaccharide carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. Starch is produced by all green plants as an energy store. It is the most important carbohydrate in the human diet and is contained in such staple foods as rice, wheat, maize (corn), potatoes and cassava.

Pure starch is a white, tasteless and odorless powder that is insoluble in cold water or alcohol. It consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin.^[1] Glycogen, the glucose store of animals, is a more branched version of amylopectin.

Starch can be used as a thickening, stiffening or gluing agent when dissolved in warm water, giving wheatpaste.

Contents 1 Name 2 History 3 Energy store of plants 3.1 Biosynthesis 4 Properties 4.1 Structure 4.2 Hydrolysis 4.3 Digestibility 4.4 Dextrinization 5 Starch as food 5.1 Modified starch 5.2 Use as food additive 5.3 Starch sugars 6 Industrial applications 7 Tests 8 See also 9 References 10 External links

Name

The word "starch" is derived from Middle English sterchen, meaning to stiffen. "Amylum" is Latin for starch, from the Greek "amulon" which means "not ground at a mill". The root amyl is used in biochemistry for several compounds related to starch.

History

Wheat starch paste was used by Egyptians to stiffen cloth and during weaving linen and possibly to glue papyrus.^[2]. Romans used it also in cosmetic creams, to powder the hair and to thicken sauces. Persians and Indians used it to make dishes similar to gothumai bushnatic wheat halva. In China, with the invention of paper, rice starch was used as a surface treatment of the paper.

Energy store of plants

In photosynthesis, plants use light energy to produce glucose from carbon dioxide. The glucose is stored mainly in the form of starch granules, in plastids such as chloroplasts and especially amyloplasts. Toward the end of the growing season, starch accumulates in twigs of trees near the buds. Fruit, seeds, rhizomes, and tubers store starch to prepare for the next growing season.

Glucose is soluble in water, hydrophilic, binds much water and then takes up much space; glucose in the form of starch, on the other hand, is not soluble and can be stored much more compactly.

Since starch is a reserve sugar for the plant, glucose molecules are bound in starch by the easily hydrolyzed alpha bonds. The same type of bond can also be seen in the animal reserve polysaccharide glycogen. This is in contrast to many structural polysaccharides such as chitin, cellulose and peptidoglycan, which are bound by beta-ties and are much more resistant to hydrolysis.

Biosynthesis

Plants produce starch by first converting glucose 1-phosphate to ADP-glucose using the enzyme glucose-1-phosphate adenylyltransferase. This step requires energy in the form of ATP. The enzyme starch synthase then adds the ADP-glucose via a 1,4-alpha glycosidic bond to a growing chain of glucose residues, liberating ADP and creating amylose. Starch branching enzyme introduces 1,6-alpha glycosidic bonds between these chains, creating the branched amylopectin. The starch debranching enzyme isoamylase removes some of these branches. Several isoforms of these enzymes exist, leading to a highly complex synthesis process.^[3]

While amylose was traditionally thought to be completely unbranched, it is now known that some of its molecules contain a few branch points.^[4]

Glycogen and amylopectin have the same structure, but the former has about one branch point per ten 1,4-alpha bonds, compared to about one branch point per thirty 1,4-alpha bonds in amylopectin.^[5] Another difference is that glycogen is synthesised from UDP-glucose while starch is synthesised from ADP-glucose.

Properties

Structure

Starch molecules arrange themselves in the plant in semi-crystalline granules. Each plant species has a unique starch granular size: rice starch is relatively small (about 2μm) while potato starches have larger granules (up to 100μm). Although in absolute mass only about one quarter of the starch granules in plants consist of amylose, there are about 150 times more amylose molecules than amylopectin molecules. Amylose is a much smaller molecule than amylopectin.

Starch becomes soluble in water when heated. The granules swell and burst, the semi-crystalline structure is lost and the smaller amylose molecules start leaching out of the granule, forming a network that holds water and increasing the mixture's viscosity. This process is called starch gelatinization. During cooking the starch becomes a paste and increases further in viscosity. During cooling or prolonged storage of the paste, the semi-crystalline structure partially recovers and the starch paste thickens, expelling water. This is mainly caused by the retrogradation of the amylose. This process is responsible for the hardening of bread or staling, and for the water layer on top of a starch gel (syneresis).

Some cultivated plant varieties have pure amylopectin starch without amylose, known as waxy starches. The most used is waxy maize, others are glutinous rice, waxy potato starch. Waxy starches have less retrogradation, resulting in a more stable paste. High amylose starch, amylomaize, is cultivated for the use of its gel strength.

Hydrolysis

The enzymes that break down or hydrolyze starch into the constituent sugars are known as amylases.

Alpha-amylases are found in plants and in animals. Human saliva is rich in amylase, and the pancreas also secretes the enzyme. Individuals from populations with a high-starch diet tend to have more amylase genes than those with low-starch diets; chimpanzees have very few amylase genes. It is possible that turning to a high-starch diet was a significant event in human evolution.^[6]

Beta-amylase cuts starch into maltose units. This process is important in the digestion of starch and is also used in brewing, where the amylase from the skin of the seed grains is responsible for converting starch to maltose (Malting, Mashing).

Digestibility

Digestive enzymes have problems digesting crystalline structures. Raw starch will digest poorly in the duodenum and small intestine, while bacterial degradation will take place mainly in the colon. Resistant starch is starch that escapes digestion in the small intestine of healthy individuals. In order to increase the digestibility, starch is cooked. Hence, before humans started using fire, eating grains was not a very useful way to get energy.

Dextrinization

If starch is subjected to dry heat, it breaks down to form pyrodextrins, in a process known as dextrinization. Pyrodextrins are brown in color. This process is partially responsible for the browning of toasted bread.

Starch as food

Starch is the most important carbohydrate in the human diet and is contained in many staple foods. The major sources of starch intake worldwide are rice, wheat, maize (corn), potatoes and cassava. Widely used prepared foods containing starch are bread, pancakes, cereals, noodles, pasta, porridge and tortilla.^[7]

Depending on the local climate other starch sources are used for food, such as arrowroot, arracacha, buckwheat, barley, oat, millet, rye, banana, breadfruit, canna, colacasia, katakuri, kudzu, malanga, oca, polynesian arrowroot, sago, sorghum, sweet potato, taro, water chestnut and yams. Chestnuts and edible beans, such as favas, lentils, mung bean and peas, are also rich in starch.

The starch industry extracts and refines starches from seeds, roots and tubers, by wet grinding, sieving and drying. Today, the main commercial refined starches are cornstarch, tapioca, wheat and potato starch. To a lesser extent, sources include rice, sweet potato, sago and mung bean. Historically, Florida arrowroot was also commercialized. Still starch is extracted from more than 50 types of plants.

Modified starch

A modified food starch is a starch that has been chemically modified to allow the starch to function properly under conditions frequently encountered during processing or storage, such as high heat, high shear, low pH, freeze/thaw and cooling.

When a starch is pre-cooked, it can then be used to thicken instantly in cold water. This is referred to as a pregelatinized starch. Otherwise, starch requires heat to thicken, or "gelatinize". The actual temperature depends on the type of starch.

The modified starches are E coded according to the International Numbering System for Food Additives (INS) :

• 1401 Acid-treated starch
• 1402 Alkaline-treated starch
• 1403 Bleached starch
• 1404 Oxidized starch
• 1405 Starches, enzyme-treated
• 1410 Monostarch phosphate
• 1411 Distarch glycerol
• 1412 Distarch phosphate esterified with sodium trimetaphosphate
• 1413 Phosphated distarch phosphate
• 1414 Acetylated distarch phosphate
• 1420 Starch acetate esterified with acetic anhydride
• 1421 Starch acetate esterified with vinyl acetate
• 1422 Acetylated distarch adipate
• 1423 Acetylated distarch glycerol
• 1440 Hydroxypropyl starch
• 1442 Hydroxypropyl distarch phosphate
• 1443 Hydroxypropyl distarch glycerol
• 1450 Starch sodium octenyl succinate
• 9047 Dialdehyde Starch

Some other types of modified starches commercially available are dextrins, cationic starches and carboxymethylated starches.

Use as food additive

As an additive for food processing, food starches are typically used as thickeners and stabilizers in foods such as puddings, custards, soups, sauces, gravies, pie fillings, and salad dressings, and to make noodles and pastas.

But by far the most common starch based food ingredient are starch sugars (see below) used as sweetener in many drinks and foods.

Use as a mold. Gummed sweets such as jelly beans and wine gums are not manufactured using a mold in the conventional sense. A tray is filled with native starch and leveled. A positive mold is then pressed into the starch leaving an impression of 1000 or so jelly beans. The mix is then poured into the impressions and then put into a stove to set. This method greatly reduces the number of molds that must be manufactured.

Starch is used as an excipient, a binder in medications to aid the formation of tablets.

Resistant starch is starch that escapes digestion in the small intestine of healthy individuals.

Starch sugars

Starch can be hydrolyzed into simpler carbohydrates by acids, various enzymes, or a combination of the two. The extent of conversion is typically quantified by dextrose equivalency (DE), which is roughly the fraction of the glycosidic bonds in starch that have been broken. Food products made in this way include:

• Maltodextrin, a lightly hydrolyzed (DE 10–20) starch product used as a bland-tasting filler and thickener.
• Various glucose syrup / corn syrups (DE 30–70), viscous solutions used as sweeteners and thickeners in many kinds of processed foods.
• Dextrose (DE 100), commercial glucose, prepared by the complete hydrolysis of starch.
• High fructose syrup, made by treating dextrose solutions with the enzyme glucose isomerase, until a substantial fraction of the glucose has been converted to fructose. In the United States, high fructose corn syrup is the principal sweetener used in sweetened beverages because fructose has better handling characteristics, such as microbiological stability, and more consistent sweetness/flavor. High fructose corn syrup has the same sweetness as sugar.
• Sugar alcohols, such as maltitol, erythritol, sorbitol, mannitol, hydrogenated starch hydrolysate are sweeteners made by reducing sugars.

Industrial applications

Starch adhesive.

Papermaking is the largest non-food application for starches globally, consuming millions of metric tons annually. In a typical sheet of copy paper for instance, the starch content may be as high as 8%. Both chemically modified and unmodified starches are used in papermaking. In the wet part of the papermaking process, generally called the “wet-end”, the starches used are cationic and have a positive charge bound to the starch polymer. These starch derivatives associate with the anionic or negatively charged paper fibers / cellulose and inorganic fillers. Cationic starches together with other retention and internal sizing agent help to give the necessary strength properties to the paper web to be formed in the papermaking process (wet strength), and to provide strength to the final paper sheet (dry strength).

In the dry end of the papermaking process the paper web is rewetted with a starch based solution. The process is called surface sizing. Starches used have been chemically, or enzymatically depolymerized at the paper mill or by the starch industry (oxidized starch). The size - starch solutions are applied to the paper web by means of various mechanical presses (size press). Together with surface sizing agent the surface starches impart additional strength to the paper web and additionally provide water hold out or “size” for superior printing properties. Starch is also used in paper coating as one of the binders for the coating formulation a mixture of pigments, binders and thickeners. Coated paper has improved smoothness, hardness, whiteness and gloss and thus improves printing characteristics.

Corrugated board adhesives are the next largest application of non-food starches globally. Starch glues are mostly based on unmodified native starches, plus some additive such as borax and caustic soda. Part of the starch is gelatinized to carry the slurry of uncooked starches and prevent sedimentation. This opaque glue is called a SteinHall adhesive. The glue is applied on tips of the fluting. The fluted paper is pressed to paper called liner. This is then dried under high heat, which causes the rest of the uncooked starch in glue to swell/gelatinize. This gelatinizing makes the glue a fast and strong adhesive for corrugated board production.

Another large non-food starch application is in the construction industry, where starch is used in the gypsum wall board manufacturing process. Chemically modified or unmodified starches are added to the stucco containing primarily gypsum. Top and bottom heavyweight sheets of paper are applied to the formulation, and the process is allowed to heat and cure to form the eventual rigid wall board. The starches act as a glue for the cured gypsum rock with the paper covering, and also provide rigidity to the board.

Starch is used in the manufacture of various adhesives or glues^[8] for book-binding, wallpaper adhesives, paper sack production, tube winding, gummed paper, envelop adhesives, school glues and bottle labeling.

Starch derivatives, such as yellow dextrins, can be modified by addition of some chemicals to form a hard glue for paper work; some of those forms use borax or soda ash, which are mixed with the starch solution at 50-70 °C to create a very good adhesive. Sodium silicate can be added to reinforce these formulae.

Clothing starch or laundry starch is a liquid that is prepared by mixing a vegetable starch in water (earlier preparations also had to be boiled), and is used in the laundering of clothes. Starch was widely used in Europe in the 16th and 17th centuries to stiffen the wide collars and ruffs of fine linen which surrounded the necks of the well-to-do. During the 19th century and early 20th century, it was stylish to stiffen the collars and sleeves of men's shirts and the ruffles of girls' petticoats by applying starch to them as the clean clothes were being ironed. Aside from the smooth, crisp edges it gave to clothing, it served practical purposes as well. Dirt and sweat from a person's neck and wrists would stick to the starch rather than to the fibers of the clothing, and would easily wash away along with the starch. After each laundering, the starch would be reapplied. Today, the product is sold in aerosol cans for home use.

Starch is also used to make some packing peanuts, and some drop ceiling tiles.

Textile chemicals from starch are used to reduce breaking of yarns during weaving; the warp yarns are sized, especially for cotton. Starch is also used as printing thickener.

In the printing industry, food grade starch^[9] is used in the manufacture of anti-set-off spray powder used to separate printed sheets of paper to avoid wet ink being set off.

Starch is used to produce various bioplastics, synthetic polymers that are biodegradable. An example is polylactic acid.

For body powder, powdered corn starch is used as a substitute for talcum powder, and similarly in other health and beauty products.

In oil exploration, starch is used to adjust the viscosity of drilling fluid, which is used to lubricate the drill head and suspend the grinding residue in petroleum extraction.

Glucose from starch can be further fermented to biofuel ethanol.

Hydrogen production can use starch as the raw material, using enzymes.^[10]

Starch, 800x magnified, under polarized light.

Tests

Main article: Iodine test

Iodine solution is used to test for starch; a dark blue color indicates the presence of starch. The details of this reaction are not yet fully known, but it is thought that the iodine (I₃⁻ and I₅⁻ ions) fit inside the coils of amylose, the charge transfers between the iodine and the starch, and the energy level spacings in the resulting complex correspond to the absorption spectrum in the visible light region. The strength of the resulting blue color depends on the amount of amylose present. Waxy starches with little or no amylose present will color red.

Starch indicator solution consisting of water, starch and iodine is often used in redox titrations: in the presence of an oxidizing agent the solution turns blue, in the presence of reducing agent the blue color disappears because triiodide (I₃⁻) ions break up into three iodide ions, disassembling the starch-iodine complex. A 0.3% w/w solution is the standard concentration for a starch indicator. It is made by adding 3 grams of soluble starch to 1 litre of heated water; the solution is cooled before use (starch-iodine complex becomes unstable at temperatures above 35°C).

Microscopy of starch granules - Each species of plant has a unique shape of starch granules in granular size, shape and crystallisation pattern. Under the microscope, starch grains stained with iodine illuminated from behind with polarized light show a distinctive Maltese cross effect (also known as extinction cross and birefringence).

See also

• Yeast extract
• Flour
• Distilled beverage, brewing from starch alcohol
• Baking, making starches digestable
• Cooking
• Acrylamide, present in fried potatoes

References

1. ^ Brown, W. H.; Poon, T. (2005), Introduction to organic chemistry (3rd ed.), Wiley, ISBN 0-471-44451-0 .
2. ^ Pliny the Elder, The Natural History (Pliny), Book XIII, Chapter 26, The paste used in preparation of paper
3. ^ Smith, A M (2001). "The biosynthesis of starch granules". Biomacromolecules 2 (2): 335–41. PMID 11749190. 
4. ^ David R. Lineback, "Starch", in AccessScience@McGraw-Hill.
5. ^ Stryer, Lubert; Berg, Jeremy Mark; Tymoczko, John L. (2002). "Section 11.2.2". Biochemistry (5th ed.). San Francisco: W.H. Freeman. ISBN 0-7167-3051-0. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.section.1517#1522. 
6. ^ PZ Myers, Amylase and human evolution, December 11, 2008.
7. ^ Anne-Charlotte Eliasson (2004). Starch in food: Structure, function and applications. Woodhead Publishing. ISBN 9780849325557.
8. ^ "Starch based glue". - ICI. http://www.nationalstarch.com/NationalStarch/About+Us/Our+Businesses. 
9. ^ "Spray Powder". Russell-Webb. http://www.russell-webb.com/anti_set_off_powder/soluble_anti-set-off-powder.html. Retrieved 2007-07-05. 
10. ^ Zhang YH, Evans BR, Mielenz JR, Hopkins RC, Adams MW (2007). "High-yield hydrogen production from starch and water by a synthetic enzymatic pathway". PLoS ONE 2 (5): e456. doi:10.1371/journal.pone.0000456. PMID 17520015. PMC 1866174. http://www.plosone.org/article/fetchArticle.action?articleURI=info:doi/10.1371/journal.pone.0000456. 

External links

• European Association of starch manufactures AAF
• Starch, by Martin Chaplin
• Starch - Stärke, scientific journal on starch
• Foods Source of Starch Base of USDA National Nutrient Database

v • d • e Types of Carbohydrates General: Aldose · Ketose · Pyranose · Furanose Geometry Cyclohexane conformation · Anomer · Mutarotation Monosaccharides Trioses Ketotriose (Dihydroxyacetone) · Aldotriose (Glyceraldehyde) Tetroses Ketotetrose (Erythrulose) · Aldotetroses (Erythrose, Threose) Pentoses Ketopentose (Ribulose, Xylulose) Aldopentose (Ribose, Arabinose, Xylose, Lyxose) Deoxy sugar (Deoxyribose) Hexoses Ketohexose (Psicose, Fructose, Sorbose, Tagatose) Aldohexose (Allose, Altrose, Glucose, Mannose, Gulose, Idose, Galactose, Talose) Deoxy sugar (Fucose, Fuculose, Rhamnose) >6 Heptose (Sedoheptulose) · Octose · Nonose (Neuraminic acid) Multiple Disaccharides Sucrose · Lactose · Maltose  · Trehalose · Turanose · Cellobiose Trisaccharides Raffinose · Melezitose · Maltotriose Tetrasaccharides Acarbose · Stachyose Other oligosaccharides Fructooligosaccharide (FOS) · Galactooligosaccharides (GOS) · Mannan-oligosaccharides (MOS) Polysaccharides Glucose/Glucan: Glycogen · Starch (Amylose, Amylopectin) · Cellulose · Dextrin/Dextran · Beta-glucan (Zymosan, Lentinan, Sizofiran)  · Maltodextrin Fructose/Fructan: Inulin · Levan beta 2→6 Mannose/Mannan Galactose/Galactan N-Acetylglucosamine: Chitin Major families of biochemicals Saccharides/Carbohydrates/Glycosides · Amino acids/Peptides/Proteins/Glycoproteins · Lipids/Terpenes/Steroids/Carotenoids · Alkaloids/Nucleobases/Nucleic acids · Cofactors/Phenylpropanoids/Polyketides/Tetrapyrroles

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - stive
v. tr. - stivelse, stivhed

Nederlands (Dutch)
stijven, zetmeel

Français (French)
n. - fécule, amidon
v. tr. - amidonner, empeser

Deutsch (German)
n. - Stärke, Steifheit
v. - stärken

Ελληνική (Greek)
n. - άμυλο, αμυλόκολλα, αμυλώδης τροφή, (μτφ.) τυπικότητα
v. - κολλαρίζω, κολλάρω

Italiano (Italian)
inamidare, amido

Português (Portuguese)
n. - amido (m), goma (f)
v. - engomar

Русский (Russian)
крахмал, чопорность, церемонность, крахмалить, накрахмаливать

Español (Spanish)
n. - almidón, fécula, rigidez, tiesura
v. tr. - almidonar

Svenska (Swedish)
n. - stärkelse, stelhet, formellt sätt, kläm, energi
v. - stärka ngt

中文（简体）(Chinese (Simplified))
淀粉, 古板, 拘谨, 给上浆

中文（繁體）(Chinese (Traditional))
n. - 澱粉, 古板, 拘謹
v. tr. - 給上漿

한국어 (Korean)
n. - 녹말, (세탁용의) 풀, 거북살스러움
v. tr. - (옷에) 풀을 먹이다, 거북스럽게 하다, 격식을 차리다

日本語 (Japanese)
n. - 澱粉, 洗濯のり, 元気, 堅苦しさ
v. - のり付けする

العربيه (Arabic)
‏(الاسم) نشا, نشاء (فعل) يقوي الملابس ( ياقات القمصان مثلا) باستعمال النشا‏

עברית (Hebrew)
n. - ‮עמילן, מזון עמילני, נוקשות, קשיחות, קפדנות‬
v. tr. - ‮עמלן‬

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