Maltose was discovered by Augustin-Pierre Dubrunfaut, although this discovery was not widely accepted until it was confirmed in 1872 by Irish chemist and brewer Cornelius O'Sullivan.[5][6] Its name comes from malt, combined with the suffix '-ose' which is used in names of sugars.[4]
Structure and nomenclatureedit
Carbohydrates are generally divided into monosaccharides, oligosaccharides, and polysaccharides depending on the number of sugar subunits. Maltose, with two sugar units, is a disaccharide, which falls under oligosaccharides. Glucose is a hexose: a monosaccharide containing six carbon atoms. The two glucose units are in the pyranose form and are joined by an O-glycosidic bond, with the first carbon (C1) of the first glucose linked to the fourth carbon (C4) of the second glucose, indicated as (1→4). The link is characterized as α because the glycosidic bond to the anomeric carbon (C1) is in the opposite plane from the CH 2OHsubstituent in the same ring (C6 of the first glucose). If the glycosidic bond to the anomeric carbon (C1) were in the same plane as the CH 2OH substituent, it would be classified as a β(1→4) bond, and the resulting molecule would be cellobiose. The anomeric carbon (C1) of the second glucose molecule, which is not involved in a glycosidic bond, could be either an α- or β-anomer depending on the bond direction of the attached hydroxyl group relative to the CH 2OH substituent of the same ring, resulting in either α-maltose or β-maltose.[citation needed]
An isomer of maltose is isomaltose. This is similar to maltose but instead of a bond in the α(1→4) position, it is in the α(1→6) position, the same bond that is found at the branch points of glycogen and amylopectin.[citation needed]
Propertiesedit
Like glucose, maltose is a reducing sugar, because the ring of one of the two glucose units can open to present a free aldehyde group; the other one cannot because of the nature of the glycosidic bond. Maltose can be broken down to glucose by the maltase enzyme, which catalyses the hydrolysis of the glycosidic bond.[citation needed]
Maltose in aqueous solution exhibits mutarotation, because the α and β isomers that are formed by the different conformations of the anomeric carbon have different specific rotations, and in aqueous solutions, these two forms are in equilibrium. Maltose can easily be detected by the Woehlk test or Fearon's test on methylamine.[7]
It has a sweet taste, but is only about 30–60% as sweet as sugar, depending on the concentration.[8] A 10% solution of maltose is 35% as sweet as sucrose.[9]
Sources and absorptionedit
Maltose syrup
Maltose is a malt component, a substance obtained when the grain is softened in water and germinates. It is also present in highly variable quantities in partially hydrolyzed starch products like maltodextrin, corn syrup and acid-thinned starch.[10]
Outside of plants, maltose is also (likely) found in sugarbag.[11]
In humans, maltose is broken down by various maltase enzymes, providing two glucose molecules that can be further processed: either broken down to provide energy, or stored as glycogen. The lack of the sucrase-isomaltase enzyme in humans causes sucrose intolerance, but complete maltose intolerance is extremely rare because there are four different maltase enzymes.[12]
Referencesedit
^Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-367. ISBN0-8493-0462-8..
^ abStoker, H. Stephen (2 January 2015). Organic and Biological Chemistry. Cengage Learning. ISBN9781305686458.
^ abFruton, Joseph S (1999). Proteins, Enzymes, Genes: The Interplay of Chemistry and Biology. Chelsea, Michigan: Yale University Press. p. 144. ISBN0300153597. Retrieved 21 October 2017.
^O'Sullivan, Cornelius (1872). "XXI.?On the transformation-products of starch". Journal of the Chemical Society. 25: 579–588. doi:10.1039/JS8722500579. Retrieved 11 December 2014.
^"150 Years Alfred Wöhlk :: Education :: ChemistryViews". 6 March 2018.
^Belitz, H.-D.; Grosch, Werner; Schieberle, Peter (15 January 2009). Food Chemistry. Springer Science & Business Media. p. 863. ISBN9783540699330.
^Spillane, W. J. (17 July 2006). Optimising Sweet Taste in Foods. Woodhead Publishing. p. 271. ISBN9781845691646.
^Furia, Thomas E. (2 January 1973). CRC Handbook of Food Additives, Second Edition. CRC Press. ISBN9780849305429.
^Heard, Tim (30 October 2015). The Australian Native Bee Book. Sugarbag Bees. ISBN9780646939971.
^Whelan, W. J.; Cameron, Margaret P. (16 September 2009). Control of Glycogen Metabolism. John Wiley & Sons. p. 60. ISBN9780470716885.
External linksedit
Media related to Maltose at Wikimedia Commons
, Elmhurst College Virtual Chembook.
February 15, 2024
maltose, ɔː, ɔː, also, known, maltobiose, malt, sugar, disaccharide, formed, from, units, glucose, joined, with, bond, isomer, isomaltose, glucose, molecules, joined, with, bond, unit, member, amylose, homologous, series, structural, motif, starch, when, beta,. Maltose ˈ m ɔː l t oʊ s 2 or ˈ m ɔː l t oʊ z 3 also known as maltobiose or malt sugar is a disaccharide formed from two units of glucose joined with an a 1 4 bond In the isomer isomaltose the two glucose molecules are joined with an a 1 6 bond Maltose is the two unit member of the amylose homologous series the key structural motif of starch When beta amylase breaks down starch it removes two glucose units at a time producing maltose An example of this reaction is found in germinating seeds which is why it was named after malt 4 Unlike sucrose it is a reducing sugar 5 Maltose a Maltoseb MaltoseNamesIUPAC name 4 O a D Glucopyranosyl D glucoseSystematic IUPAC name 3R 4R 5S 6R 6 hydroxymethyl 5 2R 3R 4S 5S 6R 3 4 5 trihydroxy 6 hydroxymethyl oxan 2 yl oxy oxane 2 3 4 triolIdentifiersCAS Number 69 79 4 Y3D model JSmol Interactive imageChEBI CHEBI 17306 YChEMBL ChEMBL1234209 NChemSpider 388469 a maltose Y6019 b maltose YECHA InfoCard 100 000 651EC Number 200 716 5KEGG D00044PubChem CID 6255UNII 66Y63L379N YCompTox Dashboard EPA DTXSID1023233InChI InChI 1S C12H22O11 c13 1 3 5 15 6 16 9 19 12 22 3 23 10 4 2 14 21 11 20 8 18 7 10 17 h3 20H 1 2H2 t3 4 5 6 7 8 9 10 11 12 m1 s1 YKey GUBGYTABKSRVRQ PICCSMPSSA N YInChI 1S C12H22O11 c13 1 3 5 15 6 16 9 19 12 22 3 23 10 4 2 14 21 11 20 8 18 7 10 17 h3 20H 1 2H2 t3 4 5 6 7 8 9 10 11 12 m1 s1Key GUBGYTABKSRVRQ PICCSMPSSA NSMILES O C H 1 C H O C H O C O O C H 1CO C H 2O C H C H O C H O C H 2O COProperties 1 Chemical formula C 12H 22O 11Molar mass 342 297 g mol 1Appearance White powder or crystalsDensity 1 54 g cm3Melting point 160 to 165 C 320 to 329 F 433 to 438 K anhydrous 102 103 C monohydrate Solubility in water 1 080 g mL 20 C Chiral rotation a D 140 7 H2O c 10 HazardsSafety data sheet SDS External MSDSRelated compoundsRelated SucroseLactoseTrehaloseCellobioseExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Amylase reaction consisting of hydrolyzing amylose producing maltose Contents 1 History 2 Structure and nomenclature 3 Properties 4 Sources and absorption 5 References 6 External linksHistory editMaltose was discovered by Augustin Pierre Dubrunfaut although this discovery was not widely accepted until it was confirmed in 1872 by Irish chemist and brewer Cornelius O Sullivan 5 6 Its name comes from malt combined with the suffix ose which is used in names of sugars 4 Structure and nomenclature editCarbohydrates are generally divided into monosaccharides oligosaccharides and polysaccharides depending on the number of sugar subunits Maltose with two sugar units is a disaccharide which falls under oligosaccharides Glucose is a hexose a monosaccharide containing six carbon atoms The two glucose units are in the pyranose form and are joined by an O glycosidic bond with the first carbon C1 of the first glucose linked to the fourth carbon C4 of the second glucose indicated as 1 4 The link is characterized as a because the glycosidic bond to the anomeric carbon C1 is in the opposite plane from the CH2 OH substituent in the same ring C6 of the first glucose If the glycosidic bond to the anomeric carbon C1 were in the same plane as the CH2 OH substituent it would be classified as a b 1 4 bond and the resulting molecule would be cellobiose The anomeric carbon C1 of the second glucose molecule which is not involved in a glycosidic bond could be either an a or b anomer depending on the bond direction of the attached hydroxyl group relative to the CH2 OH substituent of the same ring resulting in either a maltose or b maltose citation needed An isomer of maltose is isomaltose This is similar to maltose but instead of a bond in the a 1 4 position it is in the a 1 6 position the same bond that is found at the branch points of glycogen and amylopectin citation needed Properties editLike glucose maltose is a reducing sugar because the ring of one of the two glucose units can open to present a free aldehyde group the other one cannot because of the nature of the glycosidic bond Maltose can be broken down to glucose by the maltase enzyme which catalyses the hydrolysis of the glycosidic bond citation needed Maltose in aqueous solution exhibits mutarotation because the a and b isomers that are formed by the different conformations of the anomeric carbon have different specific rotations and in aqueous solutions these two forms are in equilibrium Maltose can easily be detected by the Woehlk test or Fearon s test on methylamine 7 It has a sweet taste but is only about 30 60 as sweet as sugar depending on the concentration 8 A 10 solution of maltose is 35 as sweet as sucrose 9 Sources and absorption edit nbsp Maltose syrupMaltose is a malt component a substance obtained when the grain is softened in water and germinates It is also present in highly variable quantities in partially hydrolyzed starch products like maltodextrin corn syrup and acid thinned starch 10 Outside of plants maltose is also likely found in sugarbag 11 In humans maltose is broken down by various maltase enzymes providing two glucose molecules that can be further processed either broken down to provide energy or stored as glycogen The lack of the sucrase isomaltase enzyme in humans causes sucrose intolerance but complete maltose intolerance is extremely rare because there are four different maltase enzymes 12 References edit Weast Robert C ed 1981 CRC Handbook of Chemistry and Physics 62nd ed Boca Raton FL CRC Press p C 367 ISBN 0 8493 0462 8 Dictionary Reference maltose Cambridge dictionary maltose a b Stoker H Stephen 2 January 2015 Organic and Biological Chemistry Cengage Learning ISBN 9781305686458 a b Fruton Joseph S 1999 Proteins Enzymes Genes The Interplay of Chemistry and Biology Chelsea Michigan Yale University Press p 144 ISBN 0300153597 Retrieved 21 October 2017 O Sullivan Cornelius 1872 XXI On the transformation products of starch Journal of the Chemical Society 25 579 588 doi 10 1039 JS8722500579 Retrieved 11 December 2014 150 Years Alfred Wohlk Education ChemistryViews 6 March 2018 Belitz H D Grosch Werner Schieberle Peter 15 January 2009 Food Chemistry Springer Science amp Business Media p 863 ISBN 9783540699330 Spillane W J 17 July 2006 Optimising Sweet Taste in Foods Woodhead Publishing p 271 ISBN 9781845691646 Furia Thomas E 2 January 1973 CRC Handbook of Food Additives Second Edition CRC Press ISBN 9780849305429 Heard Tim 30 October 2015 The Australian Native Bee Book Sugarbag Bees ISBN 9780646939971 Whelan W J Cameron Margaret P 16 September 2009 Control of Glycogen Metabolism John Wiley amp Sons p 60 ISBN 9780470716885 External links edit nbsp Media related to Maltose at Wikimedia Commons Maltose Elmhurst College Virtual Chembook Retrieved from https en wikipedia org w index php title Maltose amp oldid 1160596200, wikipedia, wiki, book, books, library,
