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.