Maltose

Maltose
Other names
4-O-α-D-Glucopyranosyl-D-glucose
Isomaltose
6-O-α-D-Glucopyranosyl-D-glucose
Identifiers
CAS number 69-79-4 YesY
PubChem 6255, 439193 (isomaltose)
ChemSpider 388329
EC-number 200-716-5
Properties[1]
Molecular formula C12H22O11
Molar mass 342.30 g/mol
Appearance white powder or crystals
Density 1.54 g/cm3
Melting point

160–165 °C (anhydrous)
102-103 °C (monohydrate)
Solubility in water 1.080 g/mL (20 °C)
Chiral rotation [α]D +140.7º (H2O, c = 10)
Hazards
MSDS External MSDS
EU Index not listed
Related compounds
Related Sucrose
Lactose
Trehalose
Cellobiose
 YesY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Maltose, or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4)bond. The isomer isomaltose has two glucose molecules linked through an α(1→6) bond. Maltose is the second member of an important biochemical series of glucose chains. Maltose is the disaccharide produced when amylase breaks down starch. It is found in germinating seeds such as Barley as they break down their starch stores to use for food.

The addition of another glucose unit yields maltotriose; further additions will produce dextrins (also called maltodextrins) and eventually starch (glucose polymer).

Maltose can be broken down into two glucose molecules by hydrolysis. In living organisms, the enzyme maltase can achieve this very rapidly. In the laboratory, heating with a strong acid for several minutes will produce the same result. Isomaltose is broken by isomaltase.

The production of maltose from germinating cereals, such as barley, is an important part of the brewing process. When barley is malted, it is brought into a condition in which the concentration of maltose-producing amylases has been maximized. Mashing is the process by which these amylases convert the cereal's starches into maltose. Metabolism of maltose by yeast during fermentation then leads to the production of ethanol and carbon dioxide.

The structure of β-maltose.


Maltose as food

Plain maltose has a sweet taste, about half as sweet as glucose and about one-sixth as sweet as fructose.

Relativesweetness.png


Maltose syrup

In Southern China, Taiwan, Hong Kong and Macau, maltose is a common ingredient in confectionery. The most common way to consume it is to put a layer of maltose between two pieces of biscuits (usually crackers).

Maltose with biscuits


External links

References

  1. ↑ 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 .