46. Asparagus is composed largely of water, about 93 per cent. The dry matter, however, is richer in protein than that of many vegetables. Asparagus contains, too, an amid compound, asparagin, which gives some of the characteristics to the vegetable.
47. Melons.—Melons contain from 8 to 10 per cent of dry matter, the larger portion of which is sugar and allied carbohydrates. The flavor is due to small amounts of essential oils and to organic acids associated with the sugars. Melons possess condimental rather than nutritive value.
Fig. 11.—Graphic
Composition Of Tomato.
48. Tomatoes.—The tomato belongs to the night-shade family, and for this reason was long looked upon with suspicion. It was first used for ornamental purposes and was called "love-apple." Gradually, as the idea of its poisonous nature became dispelled, it grew more and more popular as a food, until now in the United States it is one of the most common garden vegetables. It contains 7 per cent of dry matter, 4 per cent of which is sucrose, dextrose, and levulose. It also contains some malic acid, and a small amount of proteids, amids, cellulose, and coloring material. In the canning of tomatoes, if too much of the juice is excluded, a large part of the nutritive material is lost, as the sugars and albumins are all soluble and readily removed.[[16]] If the seeds are objectionable, they may be removed by straining and the juice added to the fleshy portion. The product then has a higher nutritive value than if the juice had been discarded with the seeds.
49. Sweet Corn.—Fresh, soft, green, sweet corn contains about 75 per cent of water. The dry matter is half starch and one quarter sugar. The protein content makes up nearly 5 per cent, a larger proportional amount than is found in the ripened corn, due to the fact that the proteids are deposited in the early stages of growth and the carbohydrates mainly in the last stages. Sweet corn is a vegetable of high nutritive value and palatability.
50. Eggplant contains a high per cent of water,—90 per cent. The principal nutrients are starch and sugar, which make up about half the weight of the dry matter. It does not itself supply a large amount of nutrients, but the way in which it is prepared, by combination with butter, bread crumbs, and eggs, makes it a nutritious and palatable dish, the food value being derived mainly from the materials with which it is combined, the eggplant giving the flavor and palatability.
51. Squash and Pumpkin.—Squash has much the same general composition and food value as beets and carrots, although it belongs to a different family. Pumpkins contain less dry matter than squash. The dry matter of both is composed largely of starch and sugar and, like many other of the vegetables, they are often combined with food materials containing a large amount of nutrients, as in pumpkin and squash pies, where the food value is derived mainly from the milk, sugar, eggs, flour, and butter or other shortening used.
52. Celery.—The dry matter of celery is comparatively rich in nitrogenous material, although the amount is small, and the larger proportion is in non-proteid form. When grown on rich soil, celery may contain an appreciable quantity of nitrates and nitrites, which have not been converted into amids and proteids. The supposed medicinal value is probably due to the nitrites which are generally present. Celery is valuable from a dietetic rather than a nutritive point of view.
53. Sanitary Condition of Vegetables.—The conditions under which vegetables are grown have much to do with their value, particularly from a sanitary point of view. Uncooked vegetables often cause the spread of diseases, particularly those, as cholera and typhoid, affecting the digestive tract. Particles of dirt containing the disease-producing organisms adhere to the uncooked vegetable and find their way into the digestive tract, where the bacteria undergo incubation. When sewage has been used for fertilizing the land, as in sewage irrigation, the vegetables are unsound from a sanitary point of view. Such vegetables should be thoroughly cleaned and also well cooked, in order to render them sterile. Vegetables to be eaten in the raw state should be dipped momentarily into boiling water, to destroy the activity of the germs present upon the surface. They may then be immediately immersed in ice-cold water, to preserve the crispness.