Maltose Formula

What is Maltose?

Maltose, also known as maltobiose or malt sugar, is a disaccharide made up of two glucose units bound together by a (1→4) bond. The two glucose molecules in the isomer isomaltose are joined by a (1→6) bond. Maltose is a two-unit member of the amylose homologous series, which is the starch's main structural motif. As alpha-amylase breaks down starch, it produces maltose by removing two glucose units at a time. This reaction can be seen in the germination of seeds, which is why it was named after malt. It is a reducing sugar, unlike sucrose.


Maltose Structure and Nomenclature


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Maltose is a form of sugar (sugar). Carbohydrates are a type of biological molecule that consists primarily of carbon (C) atoms with hydrogen (H) atoms and hydroxyl (OH) groups flanking them (H-C-OH). Most sugars with three to seven carbon atoms are called triose (three carbons), tetrose (four carbons), pentose (five carbons), hexose (six carbons), or heptose (seven carbons) (seven carbons).

Hexose D-glucose, expressed by the formula C6H12O6, is the most common monosaccharide. Glucose is found as a free monosaccharide as well as in disaccharides, which are made up of two monosaccharide units connected covalently. Each disaccharide is generated by a condensation reaction in which one molecule loses hydrogen (H) and the other gains a hydroxyl group (OH). The resulting glycosidic bond — those that connect a carbohydrate molecule to alcohol, which may be another carbohydrate — is the common linkage between sugars, whether it's between two glucose molecules or glucose and fructose, for example.

Glycosidic bonds form between carbon 1 of the first glucose molecule and carbon 4 of the second glucose molecule when two glucose molecules are connected together, as in maltose. (The carbons in glucose are numbered starting with the carbonyl group, which is the most oxidised end of the molecule.)

The OH group of carbon 1 on the first glucose on maltose has a -linkage, pointing downwards. The OH group of carbon 1 on the first glucose on cellobiose has a -linkage, pointing upwards.

Maltose, sucrose, and lactose are three popular disaccharides. They have the same chemical formula, C12H22O11, but their structures are different.

Maltose Composition

Maltose has a (1→4) glycosidic linkage between two glucose units, lactose (milk sugar) has a ß1→4 glycosidic linkage between glucose and galactose, and sucrose (common table sugar) has a glycosidic bond between carbon atom 1 of the glucose unit and carbon atom 2 of the fructose unit.

Maltose is not the only disaccharide that can be formed from two glucose molecules, despite the fact that it contains two glucose molecules. As glucose molecules form a glycosidic bond, the linkage can be either or, depending on whether the molecule bonding the carbon 1 is a -glucose or -glucose. Maltose is produced by a -linkage with the carbon 4 of a second glucose molecule, whereas cellobiose is produced by a -linkage. Maltose and cellobiose have the same formula as disaccharides, C12H22O11, but they are distinct compounds with different properties. Maltose, for example, can be hydrolyzed in the human body to monosaccharides, although cellobiose cannot. Cellobiose may be broken down by some species.

Maltotriose is generated by adding another glucose unit. Dextrins, also known as maltodextrins, and ultimately starch will result from further additions.

The IUPAC name for Maltose is  2-(hydroxymethyl)-6-[4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxyox ane-3,4,5-triol.


Maltose Properties

Maltose, like glucose, is a reducing sugar since one of the two glucose units' rings will open to present a free aldehyde group, while the other cannot due to the glycosidic bond's structure. The maltase enzyme, which catalyses the hydrolysis of the glycosidic bond, will break down maltose to glucose. 

Maltose exhibits mutarotation in an aqueous solution because the isomers produced by different conformations of the anomeric carbon have different basic rotations, and these two types are in equilibrium in aqueous solutions. The Woehlk test or Fearon's test on methylamine will easily detect maltose. It has a sweet taste, but depending on the concentration, it is just 30 – 60% as sweet as sugar. Maltose is 35% sweeter than sucrose in a 10% solution.

  • Maltose formula/ Maltose molecular formula: C12H22O11

  • Maltose molecular weight: 342.3 g/mol

  • Density: 1.54 g/cm3 

  • Solubility: 1.080 g/ml (20 °C) in water

  • Melting Point: 102-103 °C (monohydrate)


What is Maltose Chemical Formula?

Maltose chemical formula:  C12H22O11


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Maltose History and Discovery

Augustin-Pierre Dubrunfaut 'discovered' maltose, but it wasn't universally known until Cornelius O'Sullivan, an Irish chemist and brewer, verified it in 1872. Its name is derived from malt and the suffix '-ose,' which is used in sugar names.


Functions of Maltose

In the digestion of starch, maltose is an essential intermediate. Starch is a form of carbohydrate that plants use to store glucose. Starch is the most abundant polysaccharide in plant cells after cellulose. Starch is digested by animals (and plants) and converted to glucose for energy. As this starch is broken down, maltose is formed, which can then be easily digested into glucose molecules, the main free sugar circulating in the blood of higher animals and the brain and nervous system's preferred fuel. Maltose is the most common source of carbon exported from plant chloroplasts during the night.

Maltose is a fascinating compound because it is used to make alcohol. In the absence of oxygen, yeast cells convert glucose, maltose, and other sugars to ethanol through a mechanism known as fermentation. When the body is operating under anaerobic conditions, muscle cells turn glucose into lactic acid in a similar manner to obtain energy. While maltose is not found in nature, it can be made by the mouth's enzymes when starch is broken down.

Maltose, which is one-third as sweet as sucrose, has been used to sweeten foods by the Chinese since at least the seventh century.


Sources and Absorption of Maltose

Maltose is a part of malt, a substance obtained by soaking grain in water and allowing it to germinate. It's also used in partially hydrolyzed starch products like maltodextrin, corn syrup, and acid-thinned starch in varying amounts.

Maltose is broken down by maltase enzymes in humans, yielding two glucose molecules that can be processed further: either broken down for energy or preserved as glycogen. Sucrose intolerance is caused by a lack of the sucrase-isomaltase enzyme in humans, but since there are four distinct maltase enzymes, total maltose intolerance is extremely rare.

FAQs (Frequently Asked Questions)

1. Why is Maltose a Reducing Sugar?

Ans. At its hemiacetal anomeric base, maltose undergoes mutarotation. Remember that the reaction takes place in an aldehyde-containing open-chain structure. Maltose is a reducing sugar because the free aldehyde produced by ring-opening will react with Fehling's solution.

2. How Does Maltose Affect Blood Sugar?

Ans. Glucose and maltose boost blood glucose levels the fastest of all the carbohydrates, causing insulin secretion to increase. Fructose, on the other hand, has the least impact on glucose and insulin levels, but it does increase triglyceride levels.

3. What are Some Foods Which are High in Maltose?

Ans. Pancakes, sweet potatoes, French bread, fried onion rings, bagels, pizza, hamburgers, edamame, and malt-o-meal cereal are all high in maltose.