maltose or malt sugar, crystalline disaccharide (see carbohydrate). It has the same empirical formula (C₁₂H₂₂O₁₁) as sucrose and lactose but differs from both in structure (see isomer). Maltose is produced from starch by hydrolysis in the presence of diastase, an enzyme present in malt. Maltose is hydrolyzed to glucose by maltase, an enzyme present in yeast; the glucose thus formed may be fermented by another enzyme in yeast to produce ethanol. Maltose is important in the brewing of beer. It is an easily digested food.

Maltose, or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) linkage. It is the second member of an important biochemical series of glucose chains. The addition of another glucose unit yields maltotriose; further additions will produce dextrins (also called maltodextrins) and eventually starch.

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.

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.

Maltose as food

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

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

See also

• Glucose
• Maltase
• Isomaltase

References

External links

• Detailed Views of Maltose Binding Protein
• Elmhurst College Virtual Chembook