Dextrin
Encyclopedia
Dextrins are a group of low-molecular-weight carbohydrate
s produced by the hydrolysis
of starch
or glycogen
. Dextrins are mixtures of polymer
s of D-glucose
units linked by α-(1→4) or α-(1→6) glycosidic bonds.
Dextrins can be produced from starch using enzyme
s like amylase
s, as during digestion in the human body and during malting and mashing
, or by applying dry heat under acidic conditions (pyrolysis
or roasting
). The latter process is used industrially, and also occurs on the surface of bread during the baking process, contributing to flavour, colour, and crispness. Dextrins produced by heat are also known as pyrodextrins. During roasting under acid condition the starch hydrolyses and short chained starch parts partially rebranch with α-(1,6) bonds to the degraded starch molecule.
Dextrins are white, yellow, or brown powders that are partially or fully water-soluble, yielding optically active
solutions of low viscosity
. Most can be detected with iodine solution
, giving a red coloration; one distinguishes erythrodextrin (dextrin that colours red) and achrodextrin (giving no colour).
White and yellow dextrins from starch
roasted with little or no acid is called British gum.
s in remoistable envelope adhesives and paper tubes, in the mining industry as additives in froth flotation
, in the foundry
industry as green strength additives in sand casting
, as printing thickener
for batik
resist dyeing
, and as binders in gouache
paint.
White dextrins are used as:
As pyrotechnic binder and fuel
, they are added to fireworks
and sparklers, allowing them to solidify as pellets or "stars."
Due to the rebranching, dextrins are less digestible; indigestible dextrin are developed as soluble fiber supplements for food products.
Maltodextrin is a shortchain starch
sugar, gelatin hybrid base, (dextrin) used as a food additive
. It is produced also by enzymatic hydrolysis from gelatinated starch and is usually found as a creamy-white
hygroscopic spraydried powder. Maltodextrin is easily digestible, being absorbed as rapidly as glucose
, and might either be moderately sweet or have hardly any flavor at all.
The cyclical dextrins are known as cyclodextrins. They are formed by enzymatic degradation of starch by certain bacteria
, for example, Bacillus macerans. Cyclodextrins have toroidal structures formed by 6-8 glucose
residues.
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
s produced by the hydrolysis
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 starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
or glycogen
Glycogen
Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
. Dextrins are mixtures of polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
s of D-glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
units linked by α-(1→4) or α-(1→6) glycosidic bonds.
Dextrins can be produced from starch using enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s like amylase
Amylase
Amylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva, where it begins the chemical process of digestion. Food that contains much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns...
s, as during digestion in the human body and during malting and mashing
Mashing
In brewing and distilling, mashing is the process of combining a mix of milled grain , known as the "grain bill", and water, known as "liquor", and heating this mixture...
, or by applying dry heat under acidic conditions (pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...
or roasting
Roasting
Roasting is a cooking method that uses dry heat, whether an open flame, oven, or other heat source. Roasting usually causes caramelization or Maillard browning of the surface of the food, which is considered by some as a flavor enhancement. Roasting uses more indirect, diffused heat , and is...
). The latter process is used industrially, and also occurs on the surface of bread during the baking process, contributing to flavour, colour, and crispness. Dextrins produced by heat are also known as pyrodextrins. During roasting under acid condition the starch hydrolyses and short chained starch parts partially rebranch with α-(1,6) bonds to the degraded starch molecule.
Dextrins are white, yellow, or brown powders that are partially or fully water-soluble, yielding optically active
Optical rotation
Optical rotation is the turning of the plane of linearly polarized light about the direction of motion as the light travels through certain materials. It occurs in solutions of chiral molecules such as sucrose , solids with rotated crystal planes such as quartz, and spin-polarized gases of atoms...
solutions of low viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
. Most can be detected with iodine solution
Iodine test
The Iodine test is used to test for the presence of starch. Iodine solution — iodine dissolved in an aqueous solution of potassium iodide — reacts with the starch producing a purple black color. The colour can be detected visually with concentrations of iodine as low as 0.00002M at 20°C...
, giving a red coloration; one distinguishes erythrodextrin (dextrin that colours red) and achrodextrin (giving no colour).
White and yellow dextrins from starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
roasted with little or no acid is called British gum.
Uses
Yellow dextrins are used as water-soluble glueGlue
This is a list of various types of glue. Historically, the term "glue" only referred to protein colloids prepared from animal flesh. The meaning has been extended to refer to any fluid adhesive....
s in remoistable envelope adhesives and paper tubes, in the mining industry as additives in froth flotation
Froth flotation
Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in several processing industries...
, in the foundry
Foundry
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal in a mold, and removing the mold material or casting after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron...
industry as green strength additives in sand casting
Sand casting
Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material.It is relatively cheap and sufficiently refractory even for steel foundry use. A suitable bonding agent is mixed or occurs with the sand...
, as printing thickener
Textile printing
Textile printing is the process of applying colour to fabric in definite patterns or designs. In properly printed fabrics the colour is bonded with the fiber, so as to resist washing and friction...
for batik
Batik
Batik is a cloth that traditionally uses a manual wax-resist dyeing technique. Batik or fabrics with the traditional batik patterns are found in Indonesia, Malaysia, Japan, China, Azerbaijan, India, Sri Lanka, Egypt, Nigeria, Senegal, and Singapore.Javanese traditional batik, especially from...
resist dyeing
Resist dyeing
Resist dyeing is a term for a number of traditional methods of dyeing textiles with patterns. Methods are used to "resist" or prevent the dye from reaching all the cloth, thereby creating a pattern and ground. The most common forms use wax, some type of paste, or a mechanical resist that...
, and as binders in gouache
Gouache
Gouache[p], also spelled guache, the name of which derives from the Italian guazzo, water paint, splash or bodycolor is a type of paint consisting of pigment suspended in water. A binding agent, usually gum arabic, is also present, just as in watercolor...
paint.
White dextrins are used as:
- a crispness enhancer for food processingFood processingFood processing is the set of methods and techniques used to transform raw ingredients into food or to transform food into other forms for consumption by humans or animals either in the home or by the food processing industry...
, in food batters, coatings, and glazesGlaze (cooking technique)A glaze in cooking is a coating of a glossy, often sweet, sometimes savoury, substance applied to food typically by dipping, dripping, or with a brush. Egg whites and basic icings are both used as glazes...
, (E numberE numberE numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...
1400) - a textile finishing and coating agent to increase weight and stiffness of textile fabrics
- a thickening and binding agent in pharmaceuticals and paper coatingsCoated paperCoated paper is paper which has been coated by a compound to impart certain qualities to the paper, including weight, surface gloss, smoothness or reduced ink absorbency. Kaolinite or calcium carbonate are used to coat paper for high quality printing used in packaging industry and in magazines...
.
As pyrotechnic binder and fuel
Pyrotechnic composition
A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas or smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions...
, they are added to fireworks
Fireworks
Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...
and sparklers, allowing them to solidify as pellets or "stars."
Due to the rebranching, dextrins are less digestible; indigestible dextrin are developed as soluble fiber supplements for food products.
Other dextrin types
- Maltodextrin
Maltodextrin is a shortchain starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
sugar, gelatin hybrid base, (dextrin) used as a food additive
Food additive
Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...
. It is produced also by enzymatic hydrolysis from gelatinated starch and is usually found as a creamy-white
White
White is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness.White light can be...
hygroscopic spraydried powder. Maltodextrin is easily digestible, being absorbed as rapidly as glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
, and might either be moderately sweet or have hardly any flavor at all.
- Cyclodextrin
The cyclical dextrins are known as cyclodextrins. They are formed by enzymatic degradation of starch by certain bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, for example, Bacillus macerans. Cyclodextrins have toroidal structures formed by 6-8 glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
residues.
- Amylodextrin is a linear dextrin or short chained amyloseAmyloseAmylose is a linear polymer made up of D-glucose units.This polysaccharide is one of the two components of starch, making up approximately 2-30% of the structure...
(DPDegree of polymerizationThe degree of polymerization, or DP, is usually defined as the number of monomeric units in a macromolecule or polymer or oligomer molecule.For a homopolymer, there is only one type of monomeric unit andthe number-average degree of polymerization is given by...
20-30) that can be produced by enzymatic hydrolysis of the alpha-1,6 glycosidic bonds or debranching amylopectin. Amylodextrin colors blue with iodine.
- (Beta) Limit dextrin is the remaining polymer produced by enzymatic hydrolysis of amylopectine with beta amylaseAmylaseAmylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva, where it begins the chemical process of digestion. Food that contains much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns...
, which cannot hydrolyse the alpha-1,6 bonds at branch points.
- (Alpha) Limit dextrin is a short chained branched amylopectine remain, produced by hydrolysis of amylopectine with alpha amylase.
- Highly branched cyclic dextrin is a dextrin produced from enzymatic breaking pf the amylopectin in clusters and using branching enzyme to form large cyclic chains.
See also
- Modified starchModified starchModified starch, also called starch derivatives, are prepared by physically, enzymatically, or chemically treating native starch, thereby changing the properties of the starch. Modified starches are used in practically all starch applications, such as in food products as a thickening agent,...
- Starch gelatinizationStarch gelatinizationStarch gelatinization is a process that breaks down the intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites to engage more water. This irreversibly dissolves the starch granule...
- DextranDextranDextran is a complex, branched glucan composed of chains of varying lengths...
- BrewingBrewingBrewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...
- IcodextrinIcodextrinIcodextrin is a colloid osmotic agent, derived from maltodextrin, used in form of an aqueous solution for peritoneal dialysis under the trade name Extraneal, and after gynecological laparoscopic surgery for the reduction of post-surgical adhesions under the trade name Adept.-Physical and chemical...
- Dextrose equivalentDextrose equivalentDextrose equivalent is a measure of the amount of reducing sugars present in a sugar product, relative to glucose, expressed as a percentage on a dry basis. For example, a maltodextrin with a DE of 10 would have 10% of the reducing power of dextrose , while sucrose, with a DE of 120, would have...