Maltose contains two glucose units linked by an alpha-1, 4-glycosidic bond. When two glucose molecules are joined together and the configuration of the first glucose molecule is fixed in the beta-position, cellobiose is formed.
Cellobiose contains a beta-1, 4-glycosidc bond.
Maltose is the building block for starch which contains alpha-1, 4-glycosidic bonds. Alpha links can be broken down y the body, so starch is ready digested.
Maltose is used in beverages (malted milk, for example) and because it is fermented readily by yeast, it is important in the brewing of beer.
Maltose sometimes called malt sugar comes from hydrolysis of starch. It is about one third as sweet as cane sugar or sucrose, and is easily digested by humans.
Cellobiose is the building block for cellulose. Cellulose can’t be digested in the human body because the beta-linkages cannot be broken by the digestive enzyme. Therefore, cellulose is known as dietary fiber.
Cellobiose is obtained by the hydrolysis of cellulose. It has virtually no taste and is not fermented by yeast.
Maltose and cellobiose are both reducing sugars because the anomeric carbons on the right hand glucopyranose units have hemiacetal groups and are in equilibrium with aldehyde forms. For similar reason, both maltose and cellobiose exhibit mutarotation of alpha and beta anomers of the glucopyranose unit on the right.
They react with Benedicts and Fehling’s reagent and also react with phenylhydrazine to yield the characteristic phenylosazone.
The systematic name for maltose is a-D-glucopyranosyl-(1-4)-D-D-glucopyranose. Cellobiose is B-D-glucoysl-(1-4)-D-glucose.
Maltose and Cellobiose
