Page:Popular Science Monthly Volume 27.djvu/274

260 the mouth, but the pancreas, which is concerned in a later stage of digestion, is a gland so similar to the salivary glands that in ordinary cookery both are dressed and served as "sweetbreads," and its secretion, the pancreatic juice, is a liquid closely resembling saliva and containing a similar diastase, or substance that converts starch into dextrine, and from dextrine to sugar. Lehmann says, "It is now indubitably established that the pancreatic juice possesses this sugar forming power in a far higher degree than the saliva." Besides this there is another sugar-forming secretion, the "intestinal juice," which assists the graminivorous animals in the digestion of raw grain. This being the case, we should, by exercising our privilege as cooking animals, be able to assist the digestive functions of the saliva and the pancreatic and intestinal secretion, just as we help our teeth in the flour-mill; the means of doing this is offered by the diastase of malt.

In accordance with this reasoning I have made some experiments on a variety of our common vegetable foods, by simply raising them (in contact with water) to the temperature most favorable to the converting action of diastase) 140° to 150° Fahr.), and then adding a little malt-extract or malt-flour. This extract may be purchased ready made or may be prepared by soaking crushed or ground malt in warm water, leaving it for an hour or two, or longer, and then pressing out the liquid.

I find that oatmeal-porridge, when thus treated with malt or malt extract, is thinned by the conversion of the bulk of its insoluble starch into soluble dextrine; that boiled rice is similarly thinned; that a stiff jelly of arrowroot is at once rendered watery, and its conversion into dextrine is demonstrated by its altered action on a solution of iodine. Instead of instantly striking a blue-black color on admixture, only a slight brownish tinge is displayed, and not even this when the temperature has been carefully maintained.

Sago and tapioca are similarly changed, but not so completely as arrowroot. This is evidently because they contain a little nitrogenous matter and cellulose, which, when stirred, give a milkiness to the otherwise clear and limpid solution of dextrine.

Pease-pudding when thus treated behaves very instructively. Instead of remaining as a fairly uniform paste, it partially separates into paste and clear liquid, the paste being the cellulose and vegetable casein, the liquid a solution of the dextrine or converted starch. Turnips, carrots, potatoes, etc., behave similarly, the general results showing that, so far as the starch is concerned, there is no practical difficulty in obtaining a practically sufficient amount of conversion of the starch into dextrine by means of a very small quantity of maltose.

"Hasty-pudding," made of boiled flour, is similarly altered; generally speaking, the degree of visible alterations is proportionate to the amount of starch, but, the smaller the proportion and the greater that of cellulose, the more slowly the change occurs.