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Extractum Malti. Extract of Malt.

Botanical name:

Related entries: Barley

Synonym.—Malt Extract.

Extract of malt may be prepared by macerating coarsely powdered malt with an equal weight of water for six hours; then adding to the marc four times the original quantity of water, heated to about 30°, digesting for an hour at a temperature not exceeding 55°, straining with strong expression, and evaporating the strained liquid rapidly, by means of a water-bath or vacuum apparatus, at a temperature not exceeding 55°, until the resulting extract is of the consistence of thick honey. Malt and its extract are official in the U.S.P. Malt consists of the grain of barley, Hordeum distichon, Linn. (N.O. Gramineae), partially germinated and dried. It occurs in yellowish or brownish grains, with an agreeable, characteristic odour, and sweet taste. They should float on water, break with a crisp fracture, and show a whitish interior. The water-soluble portion of dried malt (about 70 per cent.) consists chiefly of dextrin and maltose, with some albumin and phosphates. Extract of malt occurs as a brown-yellow or light amber-coloured, thick, viscid liquid, having a faint pleasant characteristic odour, a sweet mucilaginous taste, and a distinct acid reaction. Its diastatic activity is destroyed at temperatures above 65°. Specific gravity about 1.375.

Soluble in all proportions of water, the solution being precipitated by strong alcohol.

Constituents.—Malt extract consists chiefly of maltose (50 per cent. or more) and dextrin, with some dextrose, and should also contain a fair proportion of diastase. The diastatic value is usually stated in terms based upon the proportion of starch it is capable of converting into sugar, or the time required to convert a fixed proportion., this is found by adding a known weight to a thin starch mucilage kept at a given temperature, and determining the time required for the total disappearance of the starch, a portion of the reaction mixture being removed from time to time and tested with iodine. Some observers record the time at which the digestion mixture ceases to give a blue colouration with iodine, while others prefer to record the point at which a red colouration is no longer produced with iodine, indicating that the intermediate product of digestion, dextrin, has also been converted into sugar. The determination of the actual quantity of sugar produced has also been used as a measure of diastatic action. This method is carried out as follows:—Mix as much potato starch as corresponds to 1 gramme of the anhydrous substance with a few mils of cold distilled water in a mortar, add the mixture to 65 mils of boiling water, and rinse the mortar with sufficient water to make the mucilage measure 80 mils; boil the mucilage for about a minute to ensure complete gelatinisation, cool to 46°, and add 2 decigrams of the extract of malt under examination, dissolved in sufficient distilled water to produce 20 mils of solution. Maintain the temperature of the mixture at 40° for half an hour, then boil to stop the diastatic action, cool, add sufficient distilled water to make the liquid measure 100 mils, and ascertain how much of the solution is required to reduce all the copper, in 10 mils of Fehling's solution, previously diluted with 40 mils of water and boiled in a porcelain beaker. From the maltose thus found deduct that introduced with the extract of malt (determined by titrating 10 mils of Fehling's solution with a solution containing 1 gramme of the extract in 100 mils), and express the diastatic power by the weight of starch converted by 100 parts of the extract . The calculations may be combined by the use of the following formula, where n is the number of mils used in the diastase titration, m is the number of mils of 1 per cent. w/v solution of extract of malt used in the maltose titration, and 1.184 is the factor 100/84.4 for calculating maltose into starch:

Weight of anhydrous starch completely converted = 1.184 (8.05/n - 1.61/m)

or,

Diastatic power or value = 592 (8.05/n - 1.61/m)

If the result so obtained is over 250, a fresh experiment should be made, using only half the above quantity of malt extract; the formula will then be

Diastatic power = 2 x 592 (8.05/n - 1.61/2m)

If the result so obtained is over 500, a further test should be made in which only one-fourth of the original quantity of malt extract is employed; then

Diastatic power 4 x 592 (8.05/n - 1.61/4m)

If necessary the quantity of malt extract may be still further reduced, so that in the test which is taken as fixing the diastatic power of the extract not more than half the starch is converted. This gives figures which are more properly comparable than is the case if the conversion is allowed to proceed further. Dried extract of malt (Extractum Malti Siccum) is a coarse, yellowish, somewhat hygroscopic powder, readily soluble in water. It contains about 75 per cent. of maltose, 1.5 per cent. of phosphates, and 5 per cent. of albuminoids, and is given in doses of from 4 to 8 grammes (1 to 2 drachms) with milk or wine, and may conveniently be given to children, spread between slices of buttered bread. It usually contains no diastase.

Action and Uses.—The medicinal value of malt extract depends upon the proportion of total solid nutritive carbohydrates it contains, and upon its diastatic action, the latter enabling it to convert the starchy constituents of food into soluble carbohydrates, chiefly maltose. But the diastase becomes inactive in an acid medium such as obtains in the stomach during digestion. The extract is given to children and adults for its nutritive properties. Children take the thick extract readily from a spoon, or it may be dissolved in a little warm milk. Many of the extracts on the market contain no diastase, the ferment having been destroyed during evaporation. Extract of malt is used as a vehicle for the administration of cod-liver oil (see Extractum Malti cum Oleo Morrhuae), and the liquid extract is given with haemoglobin, extract of cascara, and various salts, but it should be noted that extract of malt is inferior to syrup as a "cover" for bitter substances, and that satisfactory results cannot be obtained by mixing it with ferrous phosphate preparations or acids. Extract of malt should be kept in well-closed vessels, in a cool place. It becomes acid on keeping, and does not then mix so readily with the cod-liver oil.

Dose.—4 to 15 mils (1 to 4 fluid drachms).

PREPARATIONS.

Extractum Malti cum Hypophosphitibus et Oleo Morrhuae, B.P.C.—EXTRACT OF MALT WITH HYPOPHOSPHITES AND COD-LIVER OIL. Syn.—Malt and Hypophosphites with Cod-liver Oil.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti cum Oleo Morrhuae, B.P.C.—EXTRACT OF MALT WITH COD-LIVER OIL. Syn.—Malt and Cod-liver oil.
Mixes readily with milk, and is best administered in this combination. Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Ferratum, B.P.C.—FERRATED EXTRACT OF MALT.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum, B.P.C.—LIQUID EXTRACT OF MALT.
Extract of malt, by volume, 67.5; alcohol, 7.5; distilled water, to 100. Specific gravity about 1.2. More convenient in use than the thick viscid extract, but its nutritive properties are not so great. It may be added to emulsions of cod-liver oil, and is a suitable vehicle for the administration of the formates, hypophosphites, glycerophosphates, and phosphates, but does not mix well with ferrous phosphate or acids. Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Ferro, B.P.C.—LIQUID EXTRACT OF MALT WITH IRON. Syn.—Malt and Iron.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Formatibus, B.P.C.—LIQUID EXTRACT OF MALT WITH FORMATES. Syn.—Malt and Formates.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Glycerophosphatibus.—EXTRACT OF MALT WITH GLYCEROPHOSPHATES, Syn.—Malt and Glycerophosphates.
Dose.—4 to 13 mils (1 to 4 fluid drachms)
Extractum Malti Liquidum cum Haemoglobino, B.P.C.—LIQUID EXTRACT OF MALT WITH HAEMOGLOBIN. Syn.—Malt and Haemoglobin. 1 in 8.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Glycerophosphatibus, B.P.C.—LIQUID EXTRACT OF MALT WITH GLYCEROPHOSPHATES. Syn.—Malt and glycerophosphates.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Pancreatino, B.P.C.—LIQUID EXTRACT OF MALT WITH PANCREATIN. Syn.—Malt and Pancreatin.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Pepsino, B.P.C.—LIQUID EXTRACT OF MALT WITH PEPSIN. Syn.—Malt and Pepsin.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum cum Quinina et Strychnina, B.P.C.—LIQUID EXTRACT OF MALT WITH QUININE AND STRYCHNINE. Syn.—Malt and Quinine with Strychnine.
This preparation contains about 1/2 grain quinine hydrochloride, and 1/45 grain of strychnine hydrochloride in 4 fluid drachms. Dose.—8 to 15 mils (2 to 4 fluid drachms.)
Extractum Malti Liquidum et Cascarae, B.P.C.—LIQUID EXTRACT OF MALT AND CASCARA. Syn.—Malt and Cascara.
Dose.—4 to 15 mils (1 to 4 fluid drachms).
Extractum Malti Liquidum et Medullae Rubric, B.P.C.—LIQUID EXTRACT OF MALT AND RED BONE MARROW.
Dose.—4 to 15 mils (1 to 4 fluid drachms).

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.



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