A hundred years ago people thought about the nutritional value of vegetables differently than they do today.
Vegetables may be divided into two great classes:
- Coarse or fibrous vegetables, comprising roots, tubers, stems, bulbs, and leaves.
- The finer or fruity vegetables, as tomato, squash, pumpkin, green peas, corn, immature beans (shelled), cucumbers, melons, etc.
Vegetables are characterized by their large amount of cellulose; and as water enters largely into their composition, they are by no means the most nutritious diet. Food, however, in order to supply perfectly the needs of the vital economy, must contain water, and indigestible as well as nutritive elements. vegetables are therefore dietetically of great value, as they furnish large quantities of organic fluids, and are rich in those mineral elements which are necessary for maintaining the alkalinity of the blood, and for the repair of the bony structures.
Perhaps no food is more generally used by rich and poor alike in making up their daily fill of fare; yet how often the vegetable is spoiled in cooking! In the first place, the portion of the vegetable next to the skin contains the greater quantity of mineral matter and flavoring substances. Hence all thin-skinned vegetables such as carrots, oyster plant, etc. should be scraped. Others should be pared as thinly as possible.
Vegetables, like all starchy foods, should be put to cook in boiling water, as by the application of hot water, the starch grains are caused to swell and burst, and this give the starch an opportunity to escape through the cellulose.
Whenever possible, vegetables should be cooked the same day they are gathered. If necessary to keep green vegetables for any length of time, do not put them in water, as that will dissolve and destroy some of their juices. Lay them in a cool, dark place. A stone floor is best. Old vegetables should be immersed in cold water for an hour or more just before cooking, to make them more tender.
Young, tender vegetables, as lettuce, tomatoes, water cress, etc., served in the uncooked state, are valuable for the water and the potash salts they contain also for the stimulating effect they have on the appetite.
The Science of Food and Cookery (1921) by H.S. Anderson