Several vegetable substances contain considerable amounts of protein. One of these has already been mentioned,—the gluten or sticky part of bread,—and this is what has given wheat its well-deserved reputation as the best of all grains out of which to make flour for human food.
There is also another vegetable protein, called legumin, found in quite large amounts in dried beans and peas; but this is of limited food value, first because it is difficult of digestion, and secondly because with it, in dried peas and beans, are found a pungent oil and a bitter substance, which give them their peculiar strong flavor, both of which are quite irritating to the average person’s digestion. So distressing and disturbing are these flavoring substances to the civilized stomach, that, after thousands of attempts to use them more largely, it has been found that a full meal of beans once or twice a week is all that the comfort and health of the body will stand. This is really a great pity, for beans and peas are both nourishing and cheap. Nuts also contain much protein, but are both difficult of digestion and expensive.
