Diastase or malt is a vegetable ferment which has the property of converting starch into the soluble maltose. In nature it is the action of diastase which causes the ripening of fruits and vegetables by converting their starches into dextrins and sugars. Diastase is soluble in water and weak alcohol, and insoluble in strong alcohol; it is much more powerful than the ferments in saliva and the starch-splitting ferment of the pancreatic juice. It acts in alkaline solutions, but unlike the above ferments it continues to act in acid media, hence its action is not disturbed by the gastric juice.

Farinaceous meal of any kind mixed with one-eighth of its weight of ground malt forms a highly digestible combination. These malted foods are in great demand for the ling of invalids and children in any condition where the digestive power has been weakened, e.g, convalescence from fever, tuberculosis, sepsis, neurasthenia, and disorders of digestion. Malt extracts can also be made and added to any ordinary farinaceous dish.

Malt extracts are malt infusions evaporated down in vacuo at a low temperature in order not to destroy the diastatic ferment; this makes them expensive. The average percentage composition of malt extracts is as follows: -

Protein..

5 to 6 per cent

Soluble starch..

10 „15 "

Sugar..

50 „ 55 "

Ash . ..

1 " 2 "

Water..

22 „ 34 "

Malt extracts and malted foods in general are simply predigested starches, with other nutritive substances as above. A variety of malt extracts and malted foods are in the market, and these are of decided value in the treatment of many subacute and chronic diseases, such as neurasthenia, tuberculosis, and some forms of gouty dyspepsia. As foods they are, however, deficient in fats and proteins. A useful combination would be a farinaceous meal of any kind mixed with one-eighth of its weight of ground malt. The chief proprietary extracts of malt are: -

1. Kepler's Malt Extract

Kepler's Malt Extract is a thick, treacly preparation, and can be given in teaspoonful doses after meals in milk or soda-water, or it may be spread on any form of starchy food. This type of extract is a very good one to mix with cod-liver oil. It is rich in diastase.

2. Hoff's Malt Extract

Hoff's Malt Extract (or Homax) is given as a wineglass-ful with meals. It is a liquid preparation not unlike beer, and to many people is more easily taken than the sticky preparation. It can be taken diluted with water, soda-water, or milk. It contains considerable diastase, and not more than 10 per cent, of alcohol. In the author's experience it is of special value in the treatment of some forms of indigestion in gouty subjects.

3. Trommels Diastatic Extract Of Malt

Trommels Diastatic Extract Of Malt, made from barley malt - very syrupy in consistence, and sweet. A teaspoonful dose at first is enough to start with.

4. Maltine

Maltine is made from three cereals - barley, wheat, and oats. It is rich in diastase. It. is frequently given mixed with equal parts of wheat or barley flour, the mixture being used as a diluent of milk. It may be taken after meals, either plain or in various combinations, such as cod-liver oil, hypophosphitcs, etc.

Bynin, A Fluid Malt Extract Prepared By Allen & Hanbury

In the desiccated malt extracts all the water has been removed, e.g. Curtis' desiccated malt extract and Gramalt.

Malt may also be made as an infusion at home, and can be prepared freshly; it is much cheaper than the preparations above mentioned.

Malt Infusion (Sir W. Roberts).

Crushed malt, 3 ounces.

Cold water, 1/2 pint.

Mix the malt thoroughly with the cold water in a jug. Let the mixture stand nine hours. Decant off the liquid carefully, and strain this through muslin until it comes out clear and bright.

This has a colour like dark sherry, and a faint maltish taste.

It should be freshly made, as it is liable to ferment.

Malted Gruel

The gruel may be made of any farinaceous substances - oatmeal, Quaker oats, Farina, arrowroot, barley or lentil flour, preferably those from prepared flour. (For method of making gruel, see p. 296).

When cool enough to swallow, add the malt infusion or an extract of malt. About one tablespoonful of the infusion or a teaspoonful of the extract is sufficient to digest a plateful of gruel. The action is very rapid, and in a few moments the gruel becomes thin from the transformation of starch and maltose.

The malted proprietary foods in the market may be only partly converted (as in Table A, p. 182), into dextrins, maltose, and dextrose.

In some members of this group (Table A), the starch is little altered; in others, Allenbury's No. 3, Hovis babies' No. 2, and Moseley's food (Table B), considerable conversion has taken place; and it is stated that some of them, e.g. Coomb's malted food, are completely changed during the preparation, and therefore rank as completely malted foods. Mellin's food.