Popular Science Monthly/Volume 27/June 1885/The Chemistry of Cookery XXIV
|THE CHEMISTRY OF COOKERY.|
A FEW years ago the "farmer's friends" were very sanguine on the subject of using malt as a cattle-food, and at agricultural meetings throughout the country the iniquitous malt-tax was eloquently denounced because it stood in the way of the great fodder-reform. The malt-tax was repealed, and the subject fell out of sight and hearing immediately thereafter. Why was this?
The idea of malt-feeding was theoretically sound. By the malting of barley or other grain its diastase is made to act upon its insoluble starch, and to convert it more or less completely into soluble dextrine, a change which is absolutely necessary as a part of the business of digestion. Therefore, if you feed cattle on malted grain instead of raw grain, you supply them with a food so prepared that a part of the business of digestion is already done for them, and their nutrition is thereby advanced.
From what I am able to learn, the reason why this hopeful theory has not been carried out is simply that it does not "pay." The advantage to the cattle is not sufficient to remunerate the farmer for the extra cost of the malted food.
This may be the case with oxen, but it does not follow that it should be so with human beings. Cattle feed on grass, mangel-wurzels, etc., in their raw state, but we can not; and, as I have already shown, we are not even graminivorous as they are—we can not digest raw wheat, barley, oats, or maize.
We can not do this because we are not supplied with such natural grinding apparatus as they have in their mouths, and we have a much smaller supply of saliva, besides a shorter alimentary canal.
We can easily supply our natural deficiencies in the matter of grinding, and do so in our flour-mills; but at first thought the idea of finding an artificial substitute for saliva does not recommend itself. When, however, it is understood that the chief active principle of the saliva so closely resembles the diastase of grain that it has received the name of animal diastase, and is probably the same compound, the aspect of the problem changes.
Not only is this the case with the secretion from the glands surrounding 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.
I have made a malt-porridge by using ground malt, from which I sifted out as much husk as possible, instead of oatmeal. I found it rather too sweet; but, on mixing about one part of malt-flour with four or more of oatmeal, an excellent and easily-digestible porridge was obtained, and one which I strongly recommend as a most valuable food for strong people and invalids, children and adults.
Further details of these experiments would be tedious, and are not necessary, as they display no chemical changes that are new to science, and the practical results may be briefly stated without such details.
I recommend—1. The production of malt-flour by grinding and sifting malted wheat, malted barley, or malted oats, or all of these, and the retailing of this at its fair value as a staple article of human food. Every shopkeeper who sells flour or meal of any kind should sell this.
2. That this malted flour, or the extract made from it as above described, be mixed with the ordinary flour used in making pastry, biscuits, bread, etc., and with all kinds of porridge, pea-soup, and other farinaceous preparations, and that when these are cooked they should be slowly heated at first, in order that the maltose may act upon the starch at its most favorable temperature—50 or 60° below the boiling point.
3. When practicable, such preparations as porridge, pastry, pea soup, pease-pudding, etc., should be prepared by first cooking them in the usual manner, then stirring the malt-meal or malt-extract into them, and allowing them to remain for some time. This time may vary from a few hours to several days—the longer the better. I have proved by experiments on boiled rice, oatmeal porridge, pease-pudding, etc., that complete conversion may thus be effected. When the temperature of 140° to 150° is carefully obtained, the work of conversion is done in half an hour or less. At 212° it is arrested. At temperatures below 140° it proceeds with a slowness varying with the depression of temperature. The most rapid result is obtained by first cooking the food as usual, then reducing its temperature to 150 and adding the malt flour or extract, and keeping up the temperature for a short time.
4. Besides the malt-meal or malt-flour, which I presume will be preferably made from barley, I recommend the manufacture of what I may call "pearl-malt," that is, malt treated as barley is treated in the manufacture of pearl-barley. This pearl-malt may be very largely used in soups, puddings, and for other purposes evident to the practical cook. It may be found preferable to the malt-flour or meal for some of the above-named purposes, especially for making a purée like Rumford's soup. I strongly recommend such a soup to vegetarians, i. e., the Rumford soup No. 1, already described, but with the admixture of a little pearl-malt with the pearl-barley (or malt-meal failing the pearl-malt).
A small proportion of malt flour, one twentieth for example, has a considerable effect, and if a fancy price is to be paid for it such a proportion may be used; but, if it comes into sufficient demand to be subject to wholesome competition, larger proportions up to one fourth will be desirable.
In my experiments I used the malt-extract in order to render the result visible, but this is not necessary in practice. Either the extract or the flour may be used, as may be convenient. In all cases time should be allowed for the conversion of the starch to take place before raising the temperature to 212°, keeping in view the principles above explained as regards the temperature and time required for conversion.
I have not yet met with any malted maize commercially prepared, but the experiments that I have made on a small scale show that it is a very desirable product. I name it here and now (January 8, 1885) to prevent its becoming patented, as there are so many greedy people who rush to the Great Seal Office with any idea they may pick up, however trivial. Any previous publication of the invention is sufficient to frustrate the monopoly. The same applies to the other uses of malt that I have specified.
I am still unable to speak positively as to the efficiency of vegetable diastase in breaking up or effecting the hydration of cellulose and its conversion into sugar; but the following facts are promising:
I treated sago, tapioca, and rice with the maltose as above, and found that at a temperature of 140° to 150° all the starch disappeared in about half an hour, as proved by the iodine test. Still the liquid was not clear; flocculi of cellulose, etc., were suspended in it.
I kept this on the top of a stove several days, the temperature of the liquid varying from 100° to 180°, while the fire was burning, and falling to that of the atmosphere at night. The quantity of the insoluble suspended matter sensibly diminished, but it was not entirely removed.
This has led me to make further experiments, now in progress, on the ensilage of human food, with the aid of diastase. I am packing various kinds of vegetable food in small silos, adding to them varying proportions of malt-flour or malt-extract, and I hereby declare, for the benefit of would-be patentees, that this invention, whether worthless or otherwise, is mine, and can not be secured by them, as I have witnesses of the date of this writing and copy thereof. I shall certainly not patent this or any of the above inventions myself, and will prevent others from interfering with their free use in the improvement and cheapening of our food-supplies. I am also treating such vegetable food material with various acids for the same purpose, and make the same claim in reference to this.
When by these or other means we convert vegetable tissue into dextrine and sugar, as it is naturally converted in the ripening of a pear, and as it has been artificially converted in our laboratories, we shall extend our food-supplies in an incalculable degree. Swedes, turnips, mangel-wurzels, etc., will become delicate diet for invalids, horse-beans better than beef; delicate biscuits and fancy pastry, as well as ordinary bread, will be produced from sawdust and wood-shavings, plus a little leguminous flour.
This may be done now. Long ago I converted an old pocket-handkerchief and part of an old shirt into sugar. Other chemists have done the like in their laboratories. It has yet to be done in the kitchen.
I should add that the sugar referred to in all the above is not cane-sugar, but the sugar corresponding to that in the grape and in honey. It is less sweet than cane or beet sugar, and a better food.
I now conclude this series, with the expression of my firm conviction that the application of chemical science to cookery is capable of vastly extending and improving our food-supplies, and thereby of greatly increasing the numbers of prosperous human beings capable of living on the earth. This, however, demands a great deal of further experimental research.
I have done so little of this in proportion to my suggestions for further research that I fear my readers will liken these papers to those others found by Prince Hal in the pockets of Jack Falstaff: "Oh, monstrous! but one half-pennyworth of experimental bread to this intolerable deal of speculative sack!"
- I have lately learned that a patent was secured some years ago for "malt-bread," and that it is still obtainable from many bakers, who make under a license from the patentee. The "revised formula" for this, which I have just obtained, says: "Take of wheat-meal, six pounds; wheat-flour, six pounds; malt-flour, six ounces; German yeast, two ounces; salt, two ounces; water sufficient. Make into dough (without first melting the malt), prove well, and bake in tins." Malt-flour is also sold, but at fancy prices, absurdly beyond its just value.