maltose

{{chembox | Verifiedfields = changed | Watchedfields = removed | verifiedrevid = 47716923 | ImageFile = Maltose2.svg | ImageSize = | ImageName = α-Maltose | ImageCaption = α-Maltose | ImageClass = skin-invert-image | ImageFile1 = Maltose structure.svg | ImageSize1 = | ImageName1 = β-Maltose | ImageCaption1 = β-Maltose | ImageClass1 = skin-invert-image | IUPACName = α--Glucopyranosyl-(1→4)-β--glucopyranose 4-O-α-D-Glucopyranosyl-D-glucopyranose | OtherNames = | SystematicName = (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-triol | Section1 = | Section2 = | Section7 = | Section8 = }} thumb|right|260px|Amylase reaction consisting of hydrolyzing amylose, producing maltose

Maltose ( or ), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) bond. In the isomer isomaltose, the two glucose molecules are joined with an α(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. Unlike sucrose, it is a reducing sugar.