nut
Dry, one-seeded fruits, each containing a kernel and surrounded by a hard shell, are called nuts. In the botanical sense, a true nut does not split open when ripe, and its core, or kernel, is eaten in one piece. Acorns, hazelnuts, beechnuts, and sweet chestnuts are among the true nuts. Pistachio, kola, doum, and pili nuts are also included in this category.
In the popular sense, many other foods are called nuts. The most common example is the peanut, which is actually a legume. Similarly, the almond and the coconut are actually drupes, or stone fruits. The Brazil nut is actually a seed.
The pistachio tree is grown in dry lands in warm or temperate climates such as those of California, southwestern Asia, and the Mediterranean countries. Chestnuts are native to the temperate zone of the Northern Hemisphere. Some varieties are grown on the Pacific coasts of California, Oregon, and Washington. The kola nut is native to Africa and is cultivated extensively in the American tropics. The tung nut is found in China. The doum nut comes from the doum palm tree. It is native to Upper Egypt, the Sudan, Kenya, and Tanzania.
The edible portion of most nuts is the embryo. It stores large amounts of protein and fat to nourish the young seedling. The nutshell protects the kernel from contamination.
The fruits of the pistachio nut grow in clusters resembling grapes. The kernels are enclosed in a thin two-part shell. When growing conditions are favorable, the shells split.
The evergreen tree of the kola nut grows to 60 feet (18.3 meters). The 2-inch (5-centimeter) long brown nut is hand collected and dried in the sun for commercial use.
The pili nut is the edible nut of the Philippine tree Canarium ovatum. The tropical tree produces up to 70 pounds (32 kilograms) of nuts annually. The fruit is 21/4–3 inches (6–7 centimeters) long. It contains a hard, thick-shelled, triangular nut surrounded by a small amount of pulp. Pili nuts are high in fat content and easily digestible.
Not all nuts can be eaten. Some nuts are sources of oil or fat. Oil is extracted from the kernel of West Africa's palm nut and used in soaps. Other sources of oil are the dika nut of West Africa and the pine nut of Europe and America. The edible cohune nut, from a palm native to Honduras, also supplies lather-producing oil. The candlenut, found throughout the tropics, can be lighted and used like a candle. The hard part of the doum nut is polished and used as a substitute for ivory in the manufacture of buttons. The rind of the nut is used to make sweetmeats and molasses. Some nuts are used for ornamentation. Others can be poisonous. The tung nut is poisonous and contains an oil used in the manufacture of paints and varnishes. Many nuts are also processed to obtain a very fine charcoal. This charcoal is used for the absorption of gases, as in gas masks and industrial filters.
Nuts that can be eaten are sold raw or processed. They can be eaten fresh, roasted, or prepared in other ways. Chestnuts are sweet-flavored nuts. The doum nut is eaten raw. The betel nut is chewed as a narcotic by East Indians. The kola nut contains caffeine and is used as a basic ingredient in familiar cola drinks.
