Dextrins are a group of low-molecular-weight carbohydrates produced by the hydrolysis of

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

and

glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...

. Dextrins are mixtures of polymers of D- glucose units linked by α-(1→4) or α-(1→6)

glycosidic bonds A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal grou ...

. Dextrins can be produced from starch using enzymes like amylases, as during digestion in the human body and during

malting Malting is the process of steeping, germinating and drying grain to convert it into malt. The malt is mainly used for brewing or whisky making, but can also be used to make malt vinegar or malt extract. Various grains are used for malting, most ...

and

mashing In brewing and distilling, mashing is the process of combining a mix of ground grains – typically malted barley with supplementary grains such as corn, sorghum, rye, or wheat – known as the "grain bill" with water and then heating the mixtu ...

, or by applying dry heat under acidic conditions ( pyrolysis or

roasting Roasting is a cooking method that uses dry heat where hot air covers the food, cooking it evenly on all sides with temperatures of at least from an open flame, oven, or other heat source. Roasting can enhance the flavor through caramelization ...

). This procedure was first discovered in 1811 by

Edme-Jean Baptiste Bouillon-Lagrange Edme-Jean Baptiste Bouillon-Lagrange (12 July 1764, Paris – 23 August 1844) was a French chemist and pharmacist. He was a professor of chemistry at the Ecole de pharmacie of Paris, later serving as director of the school. He was owner of a pha ...

. The latter process is used industrially, and also occurs on the surface of

bread Bread is a staple food prepared from a dough of flour (usually wheat) and water, usually by baking. Throughout recorded history and around the world, it has been an important part of many cultures' diet. It is one of the oldest human-made f ...

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. Dextrins are white, yellow, or brown powder that are partially or fully water-soluble, yielding

optically active Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circul ...

solutions of low viscosity. Most of them can be detected with

iodine solution Tincture of iodine, iodine tincture, or weak iodine solution is an antiseptic. It is usually 2 to 7% elemental iodine, along with potassium iodide or sodium iodide, dissolved in a mixture of ethanol and water. Tincture solutions are characterized ...

, 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

glue Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

s in remoistenable envelope adhesives and paper tubes, in the mining industry as additives in froth flotation, in the foundry 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, as printing thickener for batik resist dyeing, and as binders in gouache paint and also in the leather industry. White dextrins are used as: * a crispness enhancer for

food processing Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing includes many forms of processing foods, from grinding grain to make raw flour to home cooking to complex industr ...

, in food batters, coatings, and glazes, ( INS number 1400) * a textile finishing and coating agent to increase weight and stiffness of textile fabrics * a thickening and binding agent in pharmaceuticals and paper coatings * a pyrotechnic binder and fuel; this is added to fireworks and sparklers, allowing them to solidify as pellets or "stars" * a stabilizing agent for certain explosive metal azides, particularly Lead(II) azide Owing to their rebranching, dextrins are less digestible. Indigestible dextrins have been developed as soluble stand-alone

fiber supplement Fibre supplements (also spelled fiber supplements) are considered to be a form of a subgroup of functional dietary fibre, and in the United States are defined by the Institute of Medicine (IOM). According to the IOM, functional fibre "consists o ...

s and for adding to processed food products.

Other types

* Maltodextrin Maltodextrin is a short-chain

sugar used as a

food additive Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...

. It is also produced by enzymatic hydrolysis from gelled starch, and is usually found as a creamy- white hygroscopic spray-dried powder. Maltodextrin is easily digestible, being absorbed as rapidly as glucose, 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, for example, ''

Paenibacillus macerans ''Paenibacillus macerans'' is a diazotroph bacterium found in soil and plants capable of nitrogen fixation and fermentation. This bacteria was originally discovered in 1905 by an Austrian biologist named Schardinger and thought to be a bacillus ...

'' (''Bacillus macerans''). Cyclodextrins have toroidal structures formed by 6-8 glucose residues. * Amylodextrin is a linear dextrin or short chained 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 with beta amylase, 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