This section is from the book "A Manual of Materia Medica and Pharmacology", by David M. R. Culbreth. Also available from Amazon: Manual of Materia Medica and Pharmacology.
The grain of one or more varieties, partially germinated artificially, and then dried at 55° C. (131° F.).
Habitat. W. Asia, China, Egypt; cultivated.
Syn. Hordeum Decorticatum (Perlatum), Maltum Hordei, Barley Malt; Fr. Orge Perle, Malt d'Orge, Dreche; Ger. Perlgerste, Perlgraupen, Malz, Gerstenmalz.
Hor'de-um, L. barley, classical Latin name, fr. horrere, bristle - i. e., spikelets pointed with an awn, or of the bristle form.
Sa-ti'vum. L. sativus, sown, cultivated, in gardens, fields - i. e., the kind used, in contradistinction to the wild-grown.
Plant. - Annual grain, culm, .6-1 M. (2-3°) high, leaves 15-37.5 Cm. (6-15') long, linear, scabrous, spike 7.5-10 Cm. (3-4') long, fruit in 2 rows, seed elliptical, 8 Mm. (J') long, flat back, angled sides, grooved front, smooth, grayish-yellow from adherent paleae, when removed brownish; deprived of outer integuments (pericarp) gives "pot barley," and by partial grinding get "pearl barley," having the integuments and a portion of the kernel removed, and ends of seeds rounded off, producing grains 2.5-4 Mm. (1/10-1/6') long, and about as broad; contains starch 60-68 p. c., protein compounds (gluten, albumin) 12 - 10 p. c., oil 2-3 p. c, cellulose 8-12 p. c. Malt, in yellowish, amber-colored grains, crisp when fractured, interior nearly white, agreeable, characteristic odor, sweet taste, due to conversion of the starch in the seed to maltose through the action of diastase, floats in cold water; capable of converting 5 times its weight of starch into sugars. Tests: 1. The solid soluble constituents from evaporating aqueous infusion (5 p. c.) to dryness should be 70 p. c. of the malt taken. 2. The acidity of malt, calculated as lactic acid, should not exceed .3 p. c. Solvent: cold water dissolves about 70 p. c. Dose, ad libitum.
Commercial. - Barley seeds are soaked in water, placed in heaps, when heat is generated spontaneously, being prevented from rising too high by occasional turning; germination takes place, and when the germ (acrospire) has acquired the proper length (1/3 of grain), the grain is dried rapidly to kill the embryo, thereby arresting further action of diastase, hence conversion of starch to maltose, sprouts removed, and thus constitutes malt. According to degree of heat used in drying will be obtained the pale, pale-amber, or amber-brown varieties; the grain increases 9 p. c. in size, but loses 20 p. c. in weight, becoming soft and easily crumbled.
Constituents. - Diastase .2-1 p. c, peptose (converts albumin to peptones), dextrose, sugar, starch.
Diastasum, Diastase. - (Syn., Fr. Diastase; Ger. Diastase.) This mixture containing amylolytic enzymes is obtained from an infusion of malt (barley, oat, wheat, potato), by adding a little alcohol
Fig. 29. - Barley starch.
(to overcome viscidity, coagulate albumin, etc.), filtering, adding alcohol sufficient to precipitate the diastase along with other substances; purify by redissolving 2-3 times in water and precipitating with alcohol. It is a yellowish-white, amorphous powder, translucent scales; odorless, tasteless: soluble in water with turbidity, insoluble in alcohol; converts starch into dextrin and maltose, and not less than 50 times its weight of potato starch into sugars; amylolytic power gradually lost on keeping, destroyed by heating its solutions above 85° C. (185° F.), or by adding much acid, and is diminished by the presence of acids or alkalies. Taka-Diastase, a kindred ferment, is produced by the action of the fungus, Aspergillus Ory'zae, upon steamed rice or sterilized bran. It is a yellowish-white, hygroscopic, nearly tasteless powder, soluble in water; claimed to convert 100 times its weight of starch into sugar (glucose) within 10 minutes; used in preparing the Japanese national drink, "Sake" and in converting maize into sugar in the production of whisky. Dose, gr. 5-8 (.3-.5 Gm.), alone or with pepsin, usually just after meals.
Preparation. - 1. Extraction Malti. Extract of Malt. (Syn., Ext. Malt.; Fr. Extrait (Essence) de Malt; Ger. Malzextrakt.)
Manufacture: Macerate for 6 hours 100 Gm. with water 100 Ml. (Cc.), add water 400 Ml. (Cc.), digest for 1 hour at 60° C. (140° F.) on water-bath, strain, express, filter, evaporate on water-bath or in vacuum apparatus at 60° C. (140° F.) until sp. gr. 1.350-1.400 - consistency of thick honey; yield 65-75 p. c. It is a brownish-yellow, thick or semi-fluid liquid, slight odor, sweet, mucilaginous taste, acid reaction, soluble in water, turbid, then flocculent precipitate with alcohol, tannin, alkaloidal reagents, mercuric chloride, gradually liquefies starch-paste, which will not become blue with iodine; contains water 20-25 p. c., maltose 48-70 p. c, dextrin 2-16 p. c, diastase 1-2 p. c., proteids 8 p. c., phosphoric acid .3-.4 p. c, lactic acid .75-1.5 p. c, ash 1.5 p. c. Should be kept cool, in well-closed containers. Dose, 3j-4 (4-15 Gm.).
Properties and Uses. - Barley: As a nutritive in bronchial affections, sore throat, febrile diseases, pulmonary and urinary disorders; Malt: Yields to cold water its active constituents (diastase .2-1 p. c, dextrin, sugar, starch), producing an infusion or wort which by adding hops and fermenting gives several kinds of malted liquors (ale, porter, lager beer, brown stout, etc.) - infusion may be used in wasting diseases, cholera infantum, diarrhoea; Extract: Good for dyspepsia, phthisis, wasting diseases, as an emulsifying agent, as a basis for cod-liver oil emulsion; dry extract as food for infants.