[Sidenote: Action of enzyms during digestion]
If, however, the grain be subjected to prolonged heating with water, partial solution takes place. The entire mass becomes mushy and permeated with moisture. When such a mass is brought in contact with the digestive fluids, it mixes or disintegrates with the fluid, just as molasses would mix with water. The result is that the whole mass of material is subjected to the action of the digestive fluids at once, with the result that the mass is passed from the stomach too quickly, causing congestion in the small intestines, or the whole is arrested, and fermentation and decomposition take place. In normal digestion, the enzyms are continuously secreted for a period of several hours. They begin work on the outside of the food particles, dissolving the substances gradually. Thus the enzyms are continuously used up, and the digestion proceeds slowly, but naturally, yet as fresh enzyms are continuously being secreted to act on the newly exposed surfaces, active and complete digestion is constantly taking place.
[Sidenote: Predigested "breakfast foods"]
The alleged predigestion of certain proprietary foods has neither scientific basis nor virtue. That the juices of some fruits which are already in the form of glucose, can be immediately absorbed into the tissues without any digestive process, does not prove that the mushy cooking, malting, and other forms of so-called predigestion are beneficial. The so-called "predigested breakfast foods" are not and cannot be prepared by any process for final digestion, but are in an intermediate state between starch and glucose. They are composed of a semi-soluble starch, gummy dextrin, and perhaps a little maltose which has a tendency to disturb and to interfere with the normal process of digestion.
[Sidenote: Comparative digestibility of cooked and uncooked starch]
I do not advocate the use of uncooked grain, but I wish to correct a popular error in regard to the digestibility of uncooked cereal starch. Nearly all works on physiology and diet make the statement without reserve that raw starch is indigestible. This theory has been established by putting samples of cooked and uncooked starch into two test tubes, and treating them with some digestive enzym. The cooked starch, being soluble, is all exposed to the digestive enzyms at one time, and started on its way through the numerous changes in the complex chemical process of changing starch into glucose, while in the sample of uncooked starch, the digestive enzym attacks the particles from the outside, and slowly digests or eats off the exterior of the starch grains. After a given length of time the chemist adds iodin to the two test tubes. With starch, iodin gives a blue color. In the test tube containing the cooked starch, all of which has undergone a certain amount of digestion, no blue color is discerned, for no pure starch is left, while in the other tube, in which some of the particles remain unchanged, owing to the fact that Nature does all her work slowly, a blue reaction is of course obtained, and the chemist proclaims that uncooked starch is indigestible.