Yam

Yam — Yam is the common name for some species in the genus Dioscorea (family Dioscoreaceae). These are perennial herbaceous vines cultivated for the consumption of their starchy tubers in Africa, Asia, Latin America and Oceania. There are hundreds of cultivars among the cultivated species.

Yams are not sweet potatoes, but are used in a fashion similar to both sweet potatoes and potatoes.

The word yam comes from Portuguese inhame or Spanish ñame, which both ultimately derive from the Wolof word nyam, meaning “to sample” or “taste”, in other African languages it can also mean “to eat” e.g. yamyam and nyama in Hausa.

Yam tubers can grow up to 2.5 meters in length and weigh up to 70 kg (150 pounds).

The vegetable has a rough skin which is difficult to peel, but which softens after heating. The skins vary in color from dark brown to light pink.

The majority of the vegetable is composed of a much softer substance known as the “meat”. This substance ranges in color from white to bright orange in ripe yams.

Yams of African species must be cooked to be safely eaten, because various natural substances in raw yams can cause illness if consumed; the most common cooking method in Western and Central Africa is fufu. Preparing some species of yam is a time-consuming process, involving days of pounding, leaching, and boiling to remove the toxins. Yams may be served fried, boiled or pounded into a paste. In the Philippines, the purple ube variety of yam (Dioscorea alata, also known in India as ratalu or violet yam) is eaten as a sweetened dessert called halaya, and is also an ingredient in another Filipino dessert, halo halo.

Yams are high in Vitamin C, dietary fiber, Vitamin B6, potassium, and manganese; while being low in saturated fat and sodium. Vitamin C, dietary fiber and Vitamin B6 may all promote good health. Furthermore, a product that is high in potassium and low in sodium is likely to produce a good potassium-sodium balance in the human body, and so protect against osteoporosis and heart disease. Having a low level of saturated fat is also helpful for protection against heart disease.

Yam products generally have a lower glycemic index than potato products, which means that they will provide a more sustained form of energy, and give better protection against obesity and diabetes.