MALTOSE

OyeH 2011. A sugar belonging to the group of disaccharides, formed, together with dextrin, by action of malt on starch. It occurs in the leaves of plants and in germinating seeds, and, under abnormal conditions, in uriné. It was probably prepared by several chemists in the early part of the 19th cent., but it was not recognized and named until 1847, when Dubrunfout cla ified it as a tri-saccharide and named it maltose. In 1872, O’Sullivan showed that it was a di-saccharide. It may be prepared by heating starch with four times its weight of water, until a paste is produced, which is then cooled to 60° C.. Sixty grains of malt are added and the mixture is maintained at 60° C. for at least an hour. The diastase in the malt acts upon the starch producing dextrin and malt. The mixture is heated to boiling, filtered, and the solution evaporated. Pure maltose crystallizes in needles containing one molecule of water of crystallization, but commercial maltose usually Occurs as a thick syrup. It is very soluble in water, réduces ‘Fehling’s solution, and is dextrorotatory. It ferments readily with the formation of alcohol, but before fermentation it is hydrolyzed to dextrose by maltase, a ferment present in most yeasts. On boiling with dilute acids, it is hydrolyzed to glucose.