Yam (vegetable)
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 494 kJ (118 kcal) |
|
27.9 g
|
|
| Sugars | 0.5 g |
| Dietary fiber | 4.1 g |
|
0.17 g
|
|
|
1.5 g
|
|
| Vitamins | |
| Vitamin A equiv. |
(1%)
7 μg |
| Thiamine (B1) |
(10%)
0.112 mg |
| Riboflavin (B2) |
(3%)
0.032 mg |
| Niacin (B3) |
(4%)
0.552 mg |
| Pantothenic acid (B5) |
(6%)
0.314 mg |
| Vitamin B6 |
(23%)
0.293 mg |
| Folate (B9) |
(6%)
23 μg |
| Vitamin C |
(21%)
17.1 mg |
| Vitamin E |
(2%)
0.35 mg |
| Vitamin K |
(2%)
2.3 μg |
| Minerals | |
| Calcium |
(2%)
17 mg |
| Iron |
(4%)
0.54 mg |
| Magnesium |
(6%)
21 mg |
| Manganese |
(19%)
0.397 mg |
| Phosphorus |
(8%)
55 mg |
| Potassium |
(17%)
816 mg |
| Zinc |
(3%)
0.24 mg |
|
|
|
|
|
| Percentages are roughly approximated using US recommendations for adults. Source: USDA Nutrient Database |
|
Yam is the common name for some plant species in the genus Dioscorea (family Dioscoreaceae) that form edible tubers. Yams are perennial herbaceous vines cultivated for the consumption of their starchy tubers in Asia, Africa, Central and South America, and Oceania. The tubers themselves are also called "yams". There are many different cultivars of yams. Although some varieties of sweet potato (Ipomoea batatas) are also called "yam" in parts of the United States and Canada, the sweet potato is not part of the family Dioscoreaceae, but belongs in the unrelated morning glory family Convolvulaceae.
Yams are monocots, related to lilies and grasses. Native to Africa and Asia, yam tubers vary in size from that of a small potato to over 60 kg (130 lb). Over 600 varieties of yams are known, and 95% of these crops are grown in Africa.
Yams are a monocot (a plant having one embryonic seed leaf) from the Dioscoreaceae family. Sweet potatoes are a dicot (a plant having two embryonic seed leaves) from the Convolvulaceae family. Therefore, they are about as distantly related as two flowering plants can be. Culinarily, yams are starchier and drier than sweet potatoes. The table below lists some differences between yams and sweet potatoes.
Yam tubers can grow up to 1.5 m (4.9 ft) in length and weigh up to 70 kg (150 lb) and 7.6 to 15.2 cm (3.0 to 6.0 in) high. The vegetable has a rough skin which is difficult to peel, but 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 or yellow to purple or pink in mature yams.
Many cultivars of yams are found throughout the humid tropics. The most economically important are discussed below.
Dioscorea rotundata, the white yam, and D. cayenensis, the yellow yam, are native to Africa. They are the most important cultivated yams. In the past, they were considered as two separate species, but most taxonomists now regard them as the same species. Over 200 varieties between them are cultivated.
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Wikipedia