sweet potato

1. 1. A tropical American vine (Ipomoea batatas) having rose-violet or pale pink, funnel-shaped flowers, and cultivated for its fleshy tuberous orange root.
   2. The root of this vine, eaten cooked as a vegetable. Also called yam.
2. Informal. An ocarina.

Tubers of the herbaceous climbing plant Ipomoea batatas, known in Britain before the Irish potato. The flesh may be white, yellow, or pink (if carotene is present); the leaves are also edible. A 200-g portion is a rich source of vitamins A (as carotene if pink) and C; a source of iron and vitamin B₁; provides 4.5 g of dietary fibre; contains 0.4 g of fat, of which 16% is saturated; supplies 170 kcal (700 kJ).

This large edible root belongs to the morning-glory family and is native to tropical areas of the Americas. There are many varieties of sweet potato but the two that are widely grown commercially are a pale sweet potato and the darker-skinned variety Americans erroneously call "yam" (the true yam is not related to the sweet potato). The pale sweet potato has a thin, light yellow skin and a pale yellow flesh. Its flavor is not sweet and after being cooked, the pale sweet potato is dry and crumbly, much like a white baking potato. The darker variety has a thicker, dark orange skin and a vivid orange, sweet flesh that cooks to a much moister texture. Fresh sweet potatoes are available sporadically throughout the year, though not as readily during the summer months. Canned and frozen sweet potatoes are available year-round and are sometimes labeled as yams. When buying fresh sweet potatoes choose those that are small to medium in size with smooth, unbruised skins. Sweet potatoes don't store well unless the environment is just right, which is dry, dark and around 55°F. Under perfect conditions they can be stored for 3 to 4 weeks. Otherwise, store in a cool, dark place and use within a week of purchase. Do not refrigerate. Sweet potatoes-particularly the pale variety-can be substituted for regular potatoes in most recipes. They can be prepared in a variety of ways including baking, boiling and sautéing. Sweet-potato chips can now be found on some restaurant menus. Sweet potatoes are high in vitamins A and C. See also boniato; potato.

For more information on sweet potato, visit Britannica.com.

Sweet potato (Ipomoea batatas) is in the botanical family Convolvulaceae along with common plants, such as bindweed and morning glory. The generic name Ipomoea comes from the Greek words "ips," meaning bindweed, and "homoios," meaning similar. Sweet potatoes should not be confused with ordinary potatoes (Solanum tuberosum) as they are entirely unrelated, although their uses can be similar. Orange-fleshed sweet potatoes are often known as yams, especially in the southern United States, but they are quite different from true yams (Dioscorea sp.) in growth habit and use. Furthermore, unlike true yams, the greens of sweet potatoes are edible and provide an important source of food in Africa and Asia.

Identification

Sweet potato is a perennial that is usually grown as an annual. It grows from underground tuberous roots with trailing, twisting stems that can be as long as twenty feet (six meters). Leaves are variable in shape, size, and color but are generally more or less heart-shaped and green with purple markings. The single flowers are funnelshaped and white or pale purple but are rarely seen in temperate regions. Roots grow where stem nodes touch the ground, and most develop into the edible storage roots, usually four to ten storage roots per plant.

Diversity

The International Potato Center (CIP) in Peru holds the largest sweet potato gene bank in the world with more than 6,500 wild, traditional, and improved varieties. Many of these are unique to a particular country or region. For example, an anthropologist in Irian Jaya found forty different cultivars of sweet potato growing in just one community garden. In contrast, Stephen Facciola's Cornucopia II (1998) lists only twenty-five different varieties available for the whole United States. Sweet potato flesh can be white, yellow, purple, red, pink, violet, and orange, while skin color varies among yellow, red, orange, and brown. Varieties with pale yellow or white flesh are less sweet and moist than those with red, pink, or orange flesh. They also have little or no beta-carotene and higher levels of dry matter, which means their textures are drier and more mealy and they stay firmer when cooked. Sweet potatoes also vary enormously in size, shape, taste, and texture, although all are smooth-skinned with roots always tapered at both ends.

Nutrients

All varieties of sweet potato are good sources of vitamins C and E as well as dietary fiber, potassium, and iron, and they are low in fat and cholesterol (see the Table for more detail). The orange-and red-fleshed forms of sweet potato are particularly high in beta-carotene, the vitamin A precursor.

Origins

Scientists debate the exact place of origin of I. batatas, although the evidence points toward Central America rather than South America. They are no longer found growing in the wild, but it is possible that the wild Mexican sweet potato I. trifida is an ancestor. Sweet potatoes have been cultivated for more than five thousand years, and fossilized remains found in the Andes have been dated at about 8,000 years old. Genetic studies suggest the likelihood that in early times sweet potatoes were carried by the local people from island to island, spreading gradually across the Pacific from Central and South America to eastern Indonesia, New Guinea, Polynesia, and New Zealand. Christopher Columbus is credited with taking sweet potatoes from the New World back to Spain, from where they spread through the warmer regions of Europe and were transported to other parts of Asia and to Africa by Spanish and Portuguese explorers and traders. Sweet potatoes were grown in gardens by North American Indians and were an important staple food during the American Revolutionary War and the American Civil War. They were also an essential part of the diet of the slave population in southern states. Most large plantations had a sweet potato plot and root cellars beneath cabins for potato storage.

Table 1

Popularity

At the beginning of the twentieth century sweet potatoes were the second most important root crop in the United States. In 1920 the per capita consumption of sweet potatoes was thirty-one pounds (fourteen kilograms), but consumption steadily declined. In 1999 consumption was only 4 pounds (1.8 kilograms) per person (U.S. Department of Agriculture, 2000).

Sweet potatoes grow in all warm, humid areas of the world and at the beginning of the twenty-first century were the seventh largest world food crop, 95 percent of which is produced in developing countries. They are typically grown by small farmers, often on marginal ground. This crop plant has a long history of saving lives. It matures fast, is rich in nutrients, and is often the first crop planted after a natural disaster, providing abundant food for otherwise starving populations. In eastern Africa the sweet potato is known as "the protector of children" or cilera abana because it is often the only food that stands between a child's survival and starvation.

Growing Sweet Potatoes

Sweet potatoes are tropical plants that can also be grown in the summer in temperate regions as long as they have at least five frost-free months combined with fairly warm days and nights. They can be grown from vine cuttings or by planting pieces of the roots. To grow new plants, place one or more sweet potatoes in a bed of sand and cover with a couple of inches of moist, sandy soil. When the sprouts reach about 10 inches (25.4 centimeters), detach by twisting and transplant to the place they are to grow. Push sprouts about 3 inches (7.6 centimeters) into the ground and water well. Leave a distance of about 1 foot (30 centimeters) between plants and 3 feet, 3 inches (1 meter) between rows. Sweet potatoes do best in full sun with fertile, open sandy-loam soils. They also like some added manure (well rotted) and compost, although they should not be given too much nitrogen as this encourages leaf growth at the expense of root growth. They benefit from regular additions of potash. Roots will be bigger and easier to harvest if sprouts are planted into raised mounds about 1 foot (30 centimeters) high. This is particularly important in heavy or wet soil. Once established, apart from occasional weeding, sweet potatoes need little care.

Harvesting

Roots are harvested as the leaves begin to yellow in the fall. They are then brushed clean and left to cure. Traditionally curing involved stacking the potatoes in the field or garden, covering them with sand, and leaving them for several weeks. Sweet potatoes in commercial production are cured in rooms with humidity between 75 percent and 80 percent and temperatures between 80°F and 86°F (27°C and 30°C). Curing heals cuts and reduces decay and shrinkage during storage, and it converts some starches to sugars, improving the flavor. Once cured, sweet potatoes can be stored for several months, and white-fleshed varieties last as long as ten months.

In the United States most of the sweet potato crop is canned. These are usually the smaller roots. Roots of good size are sold fresh, and any that are too large are generally processed into baby food.

Buying

When buying sweet potatoes, always choose ones that are firm with even skin coloration and no signs of decay. They should never be stored in the refrigerator. Keep them in a cool, dry, well-ventilated container (a basket is ideal) at about 55°F to 60°F (13°C–16°C). Generally they should be used within two to three weeks of purchase because it is not possible to determine how long they have already been stored before purchase.

Who Grows Sweet Potatoes?

According to figures released by CIP, more than 148.77 million short tons (135 million metric tons) of sweet potatoes are grown worldwide. China is by far the largest producer with about 87 percent of the crop, nearly half of which is fed to animals. The rest of Asia accounts for 6 percent, Africa 5 percent, Latin America 1.5 percent, and the United States 0.45 percent. In most developing countries, where the sweet potato is part of the staple diet, the white-or cream-fleshed forms with a bland taste are usually grown. These potatoes have a high dry matter content, which means they are a good energy source, which is vital for a staple food. In developed countries, where the sweet potato is used more as a vegetable or for sweet dishes, the red-or orange-fleshed types are preferred for their moist flesh and sweet flavor. The U.S. sweet potato crop was worth $214,980,000 in 1999, and just under a third of the crop was grown in North Carolina. Louisiana, Mississippi, and California also grow significant quantities. The largest European producer is Portugal with only .02 percent of world production. These figures clearly illustrate that sweet potatoes are an important crop in third world countries but are a secondary foodstuff in first world countries.

Preparing and Eating

Sweet potato roots can be boiled, steamed, baked, and fried. They are also canned or dried and made into flour, cereal, and noodles. Like pumpkins, sweet potato roots are often used in sweet dishes, such as pies, puddings, biscuits, cakes, and desserts. In some countries roots are processed to produce starch and fermented to make alcohol. Cooked red-or orange-fleshed sweet potato roots are sweet, soft, and starchy with a flavor that resembles roasted chestnuts and baked squash. Sweet potatoes are prepared by scrubbing and cutting into appropriately sized pieces. Leave the skin on if they are to be baked, boiled, or steamed; peel before frying. Cooking in the skin preserves more of the nutrients. Once the roots are cooked (when a knife can be easily inserted), they can be served whole or peeled and mashed, pureed, or sieved and served as a sweet or savory vegetable, depending on what is added.

In the United States sweet potatoes are probably best known for their use in pies and as a candied vegetable. They are a traditional accompaniment to Thanksgiving dinner and often appear on the menu at other festival times, such as Christmas and Easter. Sweet potatoes can be substituted for potatoes, apples, or squash in almost any recipe. Cooked, mashed sweet potatoes are also used to replace some of the wheat flour in breads, cakes, muffins, and cookie recipes, as is sweet potato flour. Sweet potatoes cooked in their skins can be frozen. Wrap each piece in aluminum foil or freezer wrap, place into a freezer bag, and freeze.

In third world countries sweet potatoes are processed into starch, noodles, candy, desserts, and flour. This allows the farm household to extend the availability of the crop. In China, for example, sweet potato starch production has become an important cottage industry, while in Uganda sweet potatoes are sliced and dried, which allows them to be kept for about five months. The dried pieces are also ground into flour, which is then rehydrated and eaten as a thick porridge known as atapa.

Although usually the roots are eaten, young leaves and the tips of vines can be harvested, washed, and boiled as a green vegetable or added to stir-fries. All parts of the sweet potato are used as stock feed, although the roots are often cooked first.

As a Medicine

Sweet potato roots and leaves are used in folk remedies to treat illnesses as diverse as asthma, night blindness, and diarrhea. Easily digestible, they are good for the eliminative system. It is believed they bind heavy metals, so they have been used to detoxify the system.

Sweet Potatoes in Africa

In eastern and southern Africa some 3 million children under the age of five suffer from xerophthalmia or dry eye, which causes blindness. Dry eye is caused by a lack of vitamin A in the diet, and many of the affected children die within a few months of becoming blind. The yellow-and orange-fleshed varieties of sweet potatoes are high in beta-carotene, which can be converted into vitamin A in the intestines and liver. It has been shown that even small amounts of these sweet potatoes as a regular part of the diet will eliminate vitamin A deficiency in adults and children. African countries have traditionally grown white-fleshed sweet potatoes, which are low in vitamin A. A ten-year research project concluded that varieties high in beta-carotene could compete with production levels of the white-fleshed varieties and would be acceptable to local tastes. Consequently CIP and related organizations launched a regional effort to encourage African women to also grow orange-fleshed varieties.

At the same time researchers at CIP have combined parental clones of sweet potatoes to yield a group of yellow and orange potatoes with high dry matter (a characteristic of the white-fleshed forms of sweet potato) that they believe will be more acceptable to African consumers. In Kenya sweet potatoes are mostly grown in the densely populated Western Province, where often more than half the crop is destroyed by a virus. In 2000 the Kenyan Agricultural Research Institute released genetically modified sweet potatoes with increased disease resistance and assured the public that these potatoes would be largely resistant to the virus.

Twenty-First Century Changes

In the last four decades of the twentieth century the uses of sweet potatoes diversified beyond their classification as subsistence, food security, and famine-relief crops. In particular the last decade of the century saw a concentrated, coordinated effort to fully realize the potential of this crop. The hoped for result is that millions of subsistence landholders in Africa, Asia, and Latin America will be able to use sweet potatoes for food, stock food, and processed products and to generate income.

The United States is also exploring the potential of sweet potato products. A patent was granted for the production of bread made from 100 percent sweet potato flour. It is hoped that these products will appeal to consumers who are allergic to grain breads and flours. Also scientists at two different institutes in the United States have developed genetically modified sweet potatoes containing edible vaccines. One of these vaccines works against hepatitis B and the other against the Norwalk virus found in food that has not been handled or stored correctly. Edible vaccines such as these may provide cheap protection for some of the poorest people in the world.

Bibliography

Facciola, Stephen. Cornucopia II: A Sourcebook of Edible Plants. Vista, Calif.: Kampong Publications, 1998.

Herklots, G. A. C. Vegetables in South-East Asia. London: George Allen and Unwin, 1972.

International Potato Center. Available at http://www.cipotato.org.

Musau, Z. "Genetically Modified Sweet Potato Launched in Kenya." Nation, 19 August 2000.

North Carolina Sweet Potato Commission. Available at http://www.ncsweetpotatoes.com.

Onstad, Dianne. Whole Foods Companion: A Guide for Adventurous Cooks, Curious Shoppers, and Lovers of Natural Foods. White River Junction, Vt.: Chelsea Green Publishing, 1996.

U.S. Department of Agriculture, Agriculture Research Service. Nutrient Database for Standard Reference, Release 14. Washington, D.C.: Government Printing Office, 2001.

U.S. Department of Agriculture, Economic Research Service. Situation and Outlook, Vegetables and Specialties. Washington, D.C.: Economic Research Service, 2000.

Woodward, Penny. Asian Herbs and Vegetables. Flemington, Victoria: Hyland House Publishing, 2000.

—Penny Woodward

Sweet Potato
Sweet potato in flower Hemingway, South Carolina
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Solanales Family: Convolvulaceae Genus: Ipomoea Species: I. batatas
Binomial name
Ipomoea batatas L.

Raw Sweet Potato Nutritional value per 100 g (3.5 oz)
Energy 90 kcal   360 kJ
Carbohydrates     20.1 g - Sugars  4.2 g - Dietary fiber  3.0 g   Fat 0.1 g Protein 1.6 g Thiamin (Vit. B1)  0.1 mg   8% Riboflavin (Vit. B2)  0.1 mg   7% Niacin (Vit. B3)  0.61 mg   4% Pantothenic acid (B5)  0.8 mg  16% Vitamin B6  0.2 mg 15% Folate (Vit. B9)  11 μg  3% Vitamin C  2.4 mg 4% Calcium  30.0 mg 3% Iron  0.6 mg 5% Magnesium  25.0 mg 7%  Phosphorus  47.0 mg 7% Potassium  337 mg   7% Zinc  0.3 mg 3%
Percentages are relative to US recommendations for adults. Source: USDA Nutrient database

"Camote" redirects here. For the island group in the Philippines, see Camotes Islands.

The sweet potato (Ipomoea batatas), commonly called a yam in parts of the United States (especially in the southern and western portions of the country; this terminology causes some confusion with true yams) is a crop plant whose large, starchy, sweet tasting tuberous roots are an important root vegetable. The young leaves and shoots are sometimes eaten as greens. The sweet potato is only distantly related to the potato (Solanum tuberosum). It is even more distantly related to the true yam (Dioscorea species) which is native to Africa and Asia.

The genus Ipomoea that contains the sweet potato also includes several garden flowers called morning glories, though that term is not usually extended to Ipomoea batatas. Some cultivars of Ipomoea batatas are grown as ornamental plants.

This plant is a herbaceous perennial vine, bearing alternate heart-shaped or palmately lobed leaves and medium-sized sympetalous flowers. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between red, purple, brown and white. Its flesh ranges from white through yellow, orange, and purple.

Origin and distribution

Sweet potatoes in the field.

Sweet potatoes are native to the tropical parts of the Americas, and were domesticated there at least 5000 years ago. [1] [2] They spread very early throughout the region, including the Caribbean. They were also known before western exploration in Polynesia. How exactly they arrived there is the subject of a fierce debate which involves archaeological, linguistic and genetic evidence.

Sweet potatoes are now cultivated throughout tropical and warm temperate regions wherever there is sufficient water to support their growth.

According to 2004 FAO statistics world production is 127,000,000 tons [3]. The majority comes from China with a production of 105,000,000 tonnes from 49,000 km². About half of the Chinese crop is used for livestock feed [4].

Per-capita production is greatest in countries where sweet potatoes are a staple of human consumption, led by the Solomon Islands at 160 kg per person per year and Burundi at 130 kg.

In New Zealand, sweet potato is known by its Maori name, kumara. It was a staple food for Maori before European contact. Today, it is still very popular, although less popular than regular potatoes. There are about 85 commercial kumara growers, with 1,220 hectares producing 20,000 tonnes of kumara annually.

North Carolina, the leading U.S. state in sweet potato production, currently provides 40% of the annual U.S. production of sweet potatoes.

Mississippi is also a major sweet potato producing state, where they are grown on approximately 8,200 acres. Mississippi sweet potatoes contribute $19 million dollars to the economy of the state and around 150 Mississippi farmers presently grow sweet potatoes. Mississippi's top five sweet potato producing counties are Calhoun, Chickasaw, Pontotoc, Yalobusha, and Panola. The National Sweet Potato Festival is held annually the entire first week in November in Vardaman, which proclaims itself as "The Sweet Potato Capital".

The town of Benton, Kentucky celebrates the sweet potato annually with its Tater Day Festival on the first Monday of April.

Cultivation

Freshly dug sweet potato.

An ornamental sweet potato of the "Ace of Spades" cultivar

The plant does not tolerate frost. It grows best at an average temperature of 24 °C (75 °F). Depending on the cultivar and conditions, tuberous roots mature in two to nine months. With care, early-maturing cultivars can be grown as an annual summer crop in temperate areas, such as the northern USA. Sweet potatoes rarely flower when the daylight is longer than 11 hours, as is normal outside of the tropics. They are mostly propagated by stem or root cuttings or by adventitious roots called "slips" that grow out from the tuberous roots during storage. True seeds are used for breeding only.

Under optimal conditions of 85 to 90 % relative humidity at 13 to 16 °C (55 to 61 °F), sweet potatoes can keep for six months. Colder temperatures injure the roots.

They grow well in many farming conditions and have few natural enemies; pesticides are rarely needed. They can be grown in poor soils with little fertilizer. Because they are sown by vine cuttings rather than seeds, sweet potatoes are relatively easy to plant. Because the rapidly growing vines shade out weeds, little weeding is needed, and farmers can devote time to other crops. In the tropics the crop can be maintained in the ground and harvested as needed for market or home consumption. In temperate regions sweet potatoes are most often grown on larger farms and are harvested before frosts set in.

China is the largest grower of sweet potatoes; providing about 80% of the world's supply, 130 million tons were produced in one year (in 1990; about half that of common potatoes). Historically, most of China's sweet potatoes were grown for human consumption, but now most (60%) are grown to feed pigs. The rest are grown for human food and for other products. Some are grown for export, mainly to Japan. China grows 100 varieties of sweet potato.

Sweet potatoes very early became popular in the islands of the Pacific, from Japan to Polynesia. One reason is that they were favored as an emergency crop that could be relied on if other crops failed due to typhoon flooding and the like. They are featured in many favorite dishes in Japan, Taiwan, the Philippines , and other island nations. Indonesia, Vietnam, India, and some other Asian countries are also large sweet potato growers. Uganda (the third largest grower after Indonesia), Rwanda, and some other African countries also grow a large crop which is an important part of their peoples' diets. North and South America, the original home of the sweet potato, together grow less than three percent of the world's supply. Europe has only a very small sweet potato production, mostly in Portugal. In the Caribbean, a variety of the sweet potato called the boniato is very popular. Interestingly, the flesh of the boniato is cream-colored, rather than the more popular orange hue seen in other varieties. Boniatos aren't as sweet and moist as other sweet potatoes, but many people prefer their fluffier consistency and more delicate flavor. Boniatos have been grown throughout the subtropical world for centuries, but became an important commercial crop in Florida in recent years.

Sweet potatoes were an important part of the diet in the United States for most of its history, especially in the Southeast. In recent years however they have become less popular. The average per capita consumption of sweet potatoes in the United States is only about 1.5-2 kg (4 lbs) per year, down from 13 kg (31 lb) in 1920. Southerner Kent Wrench writes: "The SweetPotato became associated with hard times in the minds of our ancestors and when they became affluent enough to change their menu, the potato was served less often."

New Zealanders grow enough kumara to provide each person with 7kg (15.4 lbs) a year, and also import substantially more than this from China.

Diseases

Main article: List of sweetpotato diseases

Uses

A sweet potato.

The roots are most frequently boiled, fried, or baked. They can also be processed to make starch and a partial flour substitute. Industrial uses include the production of starch and industrial alcohol.

Culinary uses

Although the leaves and shoots are also edible, the starchy tuberous roots are by far the most important product. In some tropical areas, they are a staple food-crop. Besides starch, they are rich in dietary fiber, vitamin A, vitamin C, and vitamin B6. All cultivars are more-or-less sweet-flavored. Despite the name "sweet", it may be a good food for diabetics, as preliminary studies on animals have revealed that it helps to stabilize blood sugar levels and to lower insulin resistance.^[1]

In 1992, the Center for Science in the Public Interest compared the nutritional value of sweet potatoes to other vegetables. Considering fiber content, complex carbohydrates, protein, vitamins A and C, iron, and calcium, the sweet potato ranked highest in nutritional value. According to these criteria, sweet potatoes earned 184 points, 100 points over the next on the list, the common potato.(NCSPC)

Sweet potato varieties with dark orange flesh have more Vitamin A than those with light colored flesh and their increased cultivation is being encouraged in Africa where Vitamin A deficiency is a serious health problem. Some Americans, including television personality Oprah Winfrey, are advocating increased consumption of sweet potatoes both for their health benefits and because of their importance in traditional Southern cuisine.

Candied sweet potatoes are a side dish consisting mainly of sweet potatoes prepared with brown sugar, marshmallows, maple syrup, molasses, or other sweet ingredients. Often served on American Thanksgiving, this dish represents traditional American cooking and indigenous food.

Sweet potato pie is also a traditional favorite dish in southern U.S. cuisine.

Baked sweet potatoes are sometimes offered in restaurants as an alternative to baked potatoes. They are often topped with brown sugar and butter.

Sweet potato leaves are a common side dish in Taiwanese cuisine, often boiled with garlic and vegetable oil and dashed with salt before serving. They are commonly found at biàndāng restaurants, as well as dishes featuring the sweet potato root.

The young leaves and vine tips of sweet potato leaves are widely consumed as a vegetable West African countries (Guinea, Sierra Leone and Liberia for example). According to FAO leaflet No. 13 - 1990, sweet potato leaves and shoots are a good source of vitamins A, C, and B2 (Riboflavin), and according to research done by A. KHACHATRYAN, are an excellent source of lutein.

Steamed/Boiled chunks, for a simple and healthy snack, chunks of sweet potato may be boiled in water or cooked in the microwave.

Sweet potato chips can be sliced, fried, and eaten just like potato chips or french fries.

Japanese recipes: Boiled sweet potato is the most common way to eat it at home. Also, the use in vegetable tempura is common. Yaki-imo (roasted sweeted potato) is a delicacy in winter, sold by hawkers (apparently there are syndicates). Daigaku-imo is a baked sweet potato dessert. In Imo-gohan, slices or small blocks of sweet potato are cooked in rice. It is also served in nimono or nitsuke, boiled and flavoured with typically soy sauce, Mirin and Dashi. Because it is sweet and starchy, it is used in Imo-kinton or some other wagashi. Shōchū is a Japanese spirit made from fermentation of rice and sweet potato.

In New Zealand, Maori traditionally cooked their kumara in hangi (earth ovens). Rocks were placed on a fire in a large hole. When the fire died out, kumara and other food was wrapped in leaves and placed on the hot rocks, then covered with earth. The kumara was dug up again several hours later. The resulting food was very soft and tender, as though steamed.

In Korean cuisine, sweet potato starch is used to produce dangmyeon (cellophane noodles).

Non-culinary uses

Sweet Potato. Moche Culture. 300 A.D. Larco Museum Collection.

In South America, the juice of red sweet potatoes is combined with lime juice to make a dye for cloth. By varying the proportions of the juices, every shade from pink to purple to black can be obtained. (Verrill p. 47)

All parts of the plant are used for animal fodder.

Sweet potatoes or camotes are often found in Moche ceramics.^[2]

Several selections are cultivated in gardens as ornamental plants for their attractive foliage, including the dark-leafed cultivars 'Blackie' and 'Ace of Spades' and the chartreuse-foliaged 'Margarita'.

Ethnomedical Uses

• The aerial parts are used as a galactogogue.
• The leaves are used to treat diabetes, hookworm, hemorrhage, and abscesses.
• The tuber is used to treat asthma.

Names

Kumara for sale, Thames, The North Island, New Zealand.

Often called a yam, the sweet potato is not the Yam family, but that is only the beginning of the confusion (see yams). Nor is the sweet potato closely related to the common potato, although both are Solanales plants. The first Europeans to taste sweet potatoes were members of Columbus' expedition to Haiti in 1492. Later explorers found many varieties under an assortment of local names, but the name which stayed was the Haitian name of batata. This name was later transferred to the ordinary potato, causing a confusion from which it never recovered. The first record of the name "sweet potato" is found in the Oxford English Dictionary of 1775. Kumara is the Polynesian name for an orangey-fleshed vegetable that looks like a sweet potato, and is a tuberous relative of the morning glory, It has a rich nutty taste.

The moist-fleshed, orange cultivars of sweet potato are often referred to as "yams" in the United States. One explanation of this confusion is that Africans brought to America took to calling American sweet potatoes Nyamis, perhaps from the Fulani word nyami (to eat) or the Twi word anyinam, which refers to a true yam. The true yam, which is native to Africa and Asia, can grow up to 2 m (6 ft) in length (sometimes with knuckle-like ends) and has a scaly skin, a pinkish white center, and a thick, almost oily feel to the tongue.

In Kenya "Ngwaci" is the Kikuyu word for sweet potatoes. The Kiswahili word is "viazi vitamu", literally sweet potato.

"Batata" or "Bataka" is the commonly used word for all varieties of Potato in Marathi and Gujarati, the two languages of Western states of India.

Later on many farmers and stores began marketing American-grown sweet potatoes as yams; the name stuck. In more recent times there has been an effort to stop the use of “yam” for sweet potatoes, but this has only been partially successful. USDA branding regulations require the word “yam” to be accompanied by the words “sweet potato” when referring to these moister sweet potatoes.

Starchy, white-fleshed types are sometimes called batatas or boniatos, from generic Spanish terms for all types of sweet potato.

Substratum names used in local varieties of English include Kūmara (from Māori), as it was the staple food of the native Māori diet, in the UK and Australasia (In NSW it is sometimes spelled as "Kumera", although "sweet potato" is more common in Australia, at least in Victoria) (the term is also used in indigenous languages of Melanesia, as well as "peteita"), and camote (from Nahuatl camohtli via Spanish) in the southwestern United States.

In Hawaiʻi substratum names are used for the yellow Japanese variety and the purple Okinawan variety, both of which are commonly available in the marketplace. The local Japanese names are widely recognized, with Satsumaimo “Satsuma potato” used by recent Japanese immigrant families and yamaimo (“mountain potato”) by other groups. (Technically, yamaimo is the proper name in Japanese of the native yam; however, as in English, it is often used to refer to the sweet potato.) However, naming often depends on personal ancestry, with e.g. Sāmoan ʻumala among Sāmoans, Tagalog kamote among Filipinos, and Hawaiian ʻuala among Native Hawaiians. The orange-fleshed variety common in the mainland U.S. and sold alongside the Japanese and Okinawan cultivars is locally called "sweet potato" or "yam." The purple Okinawan sweet potato is sometimes confused with the purple yam called ube. In Vietnamese the tubers are called khoai lang and the leaves are called rau lang.

Varieties

There are seven major varieties of sweet potatoes: Jersey, Kotobuki (Japanese), Okinawan (Purple), Papa Doc, Beauregard, Garnet, Jewel, and the newest named variety, Covington. The latter four varieties are regionally called "yams" in the United States.

A unique variety of sweet potato grown in New Zealand, originally grown by the indigenous Maori, is the kumara, a red/purple variety with a unique flavor due to its isolation from other varieties. ^[3] However, the three main varieties available in New Zealand today are the Owairaka Red, Toka Gold and Beauregard. None of these are derived from the traditional Maori kumara.

Chopped and fried Sweet potato on a plate

References and external links

Wikimedia Commons has media related to:

Sweet potato

1. ^ Sweet potatoes
2. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
3. ^ Best, E. (1925) Maori agriculture : the cultivated food plants of the natives of New Zealand, with some account of native methods of agriculture, its ritual and origin myths Whitcombe and Tombs, Wellington

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• Purple sweetpotato Exotic sweetpotatoes can have purple flesh.
• Six Varieties of Sweet Potatoes Explanation of the six major varieties of sweet potatoes, with pictures of the exterior and interiors of four varieties.
• Consultative Group on International Agricultural Research (CGIAR), "Sweet Potato"
• Food and Agricultural Organization of the United Nations (FAO), 1990, "Roots, tubers, plantains and bananas in human nutrition"

"Leaflet No. 13 - 1990 - Sweet Potato"

• The Japanese Society of Root and Tuber Crops (JRT), "Mini White Paper: Sweetpotato in Japan" 2000
• North Carolina Sweet Potato Commission (NCSPC)
• Verrill, A.H., Foods America Gave the World, 1937, Boston : L.C. Page & Co.
• Wrench, K., "The Sweet Potato Patch"
• Sweetpotato DiagNotes is a free comprehensive tool for sweetpotato management, providing information across the disciplines of plant pathology, crop nutrition, entomology and pest management, all integrated in a single expert system.
• Mississippi Sweet Potato Growers Association website highlights the efforts of Wardell Sanders and his pursuits in Mound Bayou, Mississippi. The SPGA serves to provide a lasting agri-economy, strengthen the area farming communities, heighten Mississippi Delta pride, and to include Delta youth in all phases of its operations.
• Sweet Potato Awareness, education about the differences between yams and sweet potatoes, with a downloadable flyer to distribute.
• The Straight Dope answers "What's the difference between yams and sweet potatoes?"
• Identification of sweet potato leaves (Ipomoea batatas) as an excellent source of lutein. A. KHACHATRYAN
• Recipe for stir fried sweet potato leaves.
• Dining in Japan: The Purple Sweet Potato
• World's Healthiest Foods: Benefits of Sweet Potatoes

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