DIASTASE

or AMYLASE. A substance, known as an enzyme, which has the property of converting starch into maltose. It occurs very widely in nature, and is found in blood serum, in muscle, liver and.other parts of the body, and to a considerable extent in saliva. In the vegetable kingdom it occurs in leaves, twigs, seeds and other parts of a plant, and in yeast and many of the mould fungi. It a umes industrial importance by its action in the production of malt from barley, for the manufacture of beer, syrups and other products. The enzyme occurs in the barley grain, but the quantity steadily increases when the grain is germinated, (i.e.) piled in heaps, moistened and allowed to sprout. In the course of germination, the diastase acts upon the starch in the grain, and converts it to malt sugar. Diastase is prepared by a variety of methods, usually from malt. By one method, the ground malt is soaked with water for several hours, the solid matter is filtered off and the solution treated with alcohol. This causes the diastase to be thrown out of solution as a flocculent precipitate, which is then washed with alcohol and dried in vacuo. Sometimes, in place of water, dilute alcohol is used for extraction and the enzyme is frequently purified by redi olving in water and precipitating with ammonium sulphate. By any of the above methods, the diastase is obtained as an amorphous, colorle powder.