Dextrins are a group of low-molecular-weight

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...

s produced by the

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolys ...

of starch and glycogen. Dextrins are mixtures of

polymer A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

s of D-

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

units linked by α-(1→4) or α-(1→6) glycosidic bonds. Dextrins can be produced from starch using

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s like

amylase An amylase () is an enzyme that catalyses the hydrolysis of starch (Latin ') into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large amounts of ...

s, as during digestion in the human body and during malting and mashing, or by applying dry heat under acidic conditions (

pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...

or roasting). This procedure was first discovered in 1811 by Edme-Jean Baptiste Bouillon-Lagrange. The latter process is used industrially, and also occurs on the surface of bread during the baking process, contributing to flavor, color and crispness. Dextrins produced by heat are also known as pyrodextrins. Starch hydrolyses during roasting under acidic conditions, and short-chained starch parts partially rebranch with α-(1,6) bonds to the degraded starch molecule. See also

Maillard reaction The Maillard reaction ( ; ) is a chemical reaction between Amino acid, amino acids and Reducing sugar, reducing sugars that gives browned food its distinctive flavor. Searing, Seared steaks, fried dumplings, cookies and other kinds of biscuits, b ...

. Dextrins are white, yellow, or brown powder that are partially or fully water-soluble, yielding optically active solutions of low

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

. Most of them 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 are called British gum. Dextrin skeletal

Uses

Yellow dextrins are used as water-soluble glues in remoistenable envelope adhesives and paper tubes, in the mining industry as additives in

froth flotation Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in mineral processing, paper recycling and waste-water treatment industries. Historically this was first used in the mining industry, wher ...

, in the

foundry A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals pr ...

industry as

green strength Green strength, or handling strength, can be defined as the strength of a material as it is processed to form its final ultimate tensile strength. This strength is usually considerably lower than the final ultimate strength of a material. The term g ...

additives in

sand casting Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced i ...

, as printing thickener for

batik Batik is an Indonesian technique of wax-resist dyeing applied to the whole cloth. This technique originated from the island of Java, Indonesia. Batik is made either by drawing dots and lines of the resist with a spouted tool called a ''ca ...

resist dyeing Resist dyeing (resist-dyeing) is a traditional method 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 typ ...

, and as binders in

gouache Gouache (; ), body color, or opaque watercolor is a water-medium paint consisting of natural pigment, water, a binding agent (usually gum arabic or dextrin), and sometimes additional inert material. Gouache is designed to be opaque. Gouache ...

paint and also in the leather industry. White dextrins are used as: * a crispness enhancer for food processing, in food batters, coatings, and glazes, (

INS number The International Numbering System for Food Additives (INS) is a European-based naming system for food additives, aimed at providing a short designation of what may be a lengthy actual name."Class Names and the International Numbering System for Fo ...

1400) * a

textile finishing In textile manufacturing, finishing refers to the processes that convert the woven or knitted cloth into a usable material and more specifically to any process performed after dyeing the yarn or fabric to improve the look, performance, or "hand" ...

and coating agent to increase weight and stiffness of textile fabrics * a thickening and binding agent in

pharmaceutical A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field an ...

s and paper coatings * a pyrotechnic binder and fuel; this is added to

fireworks Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large number of devices ...

and

sparkler A sparkler is a type of hand-held firework that burns slowly while emitting bright, intense colored flames, sparks, and other effects. Sparklers are particularly popular with children. In the United Kingdom, a sparkler is often used by chil ...

s, allowing them to solidify as pellets or "stars" * a stabilizing agent for certain explosive metal azides, particularly

Lead(II) azide Lead(II) azide is an inorganic compound. More so than other azides, is explosive. It is used in detonators to initiate secondary explosives. In a commercially usable form, it is a white to buff powder. Preparation and handling Lead(II) azide is ...

Owing to their rebranching, dextrins are less digestible. Indigestible dextrins have been developed as soluble stand-alone fiber supplements and for adding to processed food products.

Other types

* Maltodextrin Maltodextrin is a short-chain starch sugar used as a food additive. It is also produced by enzymatic hydrolysis from gelled starch, and is usually found as a creamy-

white White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White o ...

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substan ...

spray-dried powder. Maltodextrin is easily digestible, being absorbed as rapidly as

, and might either be moderately

sweet Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketone ...

or have hardly any flavor at all. * Cyclodextrin The cyclical dextrins are known as cyclodextrins. They are formed by

enzymatic Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. ...

degradation of starch by certain

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

, for example, '' Paenibacillus macerans'' (''Bacillus macerans''). Cyclodextrins have toroidal structures formed by 6-8

residues. * Amylodextrin is a linear dextrin or short chained

amylose Amylose is a polysaccharide made of α-D-glucose units, bonded to each other through α(1→4) glycosidic bonds. It is one of the two components of starch, making up approximately 20–30%. Because of its tightly packed helical structure, amylose ...

( DP 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

amylopectin Amylopectin is a water-insoluble polysaccharide and highly branched polymer of α-glucose units found in plants. It is one of the two components of starch, the other being amylose. Plants store starch within specialized organelles called amyloplas ...

with beta

, which cannot hydrolyse the alpha-1,6 bonds at branch points. *(Alpha) Limit dextrin is a short chained branched amylopectin remnant, produced by hydrolysis of amylopectin with alpha amylase. * Highly branched cyclic dextrin is a dextrin produced from enzymatic breaking of the amylopectin in clusters and using branching enzyme to form large cyclic chains.T. Hiroki, K. Iwao, T. Noboru, S. Yuji, Y. Mikio, Journal: Seibutsu Kogakkaishi, Vol:84; No:2; Page: 61-66 (2006), Industrial Production of Branching Enzyme and Its Application to Production of Highly Branched Cyclic Dextrin (Cluster Dextri

References

External links

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EAFUS
{{Authority control Edible thickening agents Food additives Polysaccharides Pyrotechnic chemicals Starch