Specification :

Besides simple starches, sweet potatoes are rich in complex carbohydrates, dietary fiber, beta carotene ( a vitamin A equivalent nutrient) , vitamin C, and vitamin B6. Pink and yellow varieties are high in carotene, the precursor of vitamin A.

In 1992, the Center for Science in the Public Interest compared the nutritional value of sweet potatoes to other vegetables. Considering fibre 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 beta carotene than those with light coloured flesh, and their increased cultivation is being encouraged in Africa, where vitamin A deficiency is a serious health problem. Despite the name " sweet" , it may be a beneficial food for diabetics, as preliminary studies on animals have revealed that it helps to stabilize blood sugar levels and to lower insulin resistance.[ 13] 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.

The peptic substance ( 0.78 percent total, 0.43 percent soluble) present in fresh tubers contains uronic acid ( 60 percent) and methoxyl ( 4 to 5 percent) . Other constituents include phytin ( 1.05 percent) , two monoaminophosphatides ( probably lecithin and cephalin) , organic acids ( oxalic acid) , phytosterolin, phytosterol, resins, tannins, and colouring matter. ( Hug et al., 1983) .
[ edit] Culinary uses
Japanese pastry

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.
[ edit] Africa

* " Amukeke" ( sun dried slices of storage roots) and " inginyo" ( sun dried crushed storage roots) are a staple food for people in northeastern Uganda ( Abidin, 2004) . Amukeke is mainly for breakfast, eaten with peanut sauce. People generally eat this food while they are drinking a cup of tea in the morning, around 10 am. Inginyo will be mixed with cassava flour and tamarind, to make food called " atapa" . People eat " atapa" with smoked fish cooked in peanut sauce or with dried cowpea leaves cooked in peanut sauce.
* The young leaves and vine tips of sweet potato leaves are widely consumed as a vegetable in West African countries ( Guinea, Sierra Leone and Liberia, for example) , as well as in northeastern Uganda, East Africa ( Abidin, 2004) . 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 are boiled in water or cooked by microwave.

[ edit] Asia
A Japanese yaki-imo vendor and cart outside Nara Park.

* In China, sweet potatoes, typically of the yellow variety, are often baked in a large iron drum and sold as street food during winter.[ 14] . In Japan, this is called Yaki-imo ( roasted sweeted potato) and typically use the purple colored sweet potato
* Sweet potato soup is a type of Chinese tong sui ( sweet soup) that is served during in winter, consist of boiling sweet potato in water with rock sugar and ginger.
* Sweet potato greens are a common side dish in Taiwanese cuisine, often boiled or sauté ed and served with a garlic and soy sauce mixture, or simply salted before serving. They, as well as dishes featuring the sweet potato root, are commonly found at bento ( POJ: pi
n-tong) restaurants, .
* In northeastern Chinese cuisine, sweet potatoes are often cut into chunks and fried, before being drenched into a pan of boiling syrup.[ 15]
* In Korean cuisine, sweet potato starch is used to produce dangmyeon ( cellophane noodles) . Sweet potatoes are also boiled, steamed, or roasted, and young stems are eaten as namul. Pizza Restaurants such as Pizza Hut and Dominoes in Korea are using sweet potatoes as a popular topping.
* In Japan, boiled sweet potato is the most common way to eat it at home. Also, the use in vegetable tempura is common.
o Daigaku-imo is a baked sweet potato dessert.
o Because it is sweet and starchy, it is used in imo-kinton and some other wagashi ( Japanese sweets) , such as ofukuimo.
o ShMchk, a Japanese spirit normally made from the fermentation of rice, can also be made from sweet potato, in which case it is called imo-jMchk.
* Imo-gohan, sweet potato cooked with rice, is popular in both Japan and Taiwan. It is also served in nimono or nitsuke, boiled and typically flavoured with soy sauce, mirin and dashi.
* In Malaysia, sweet potato is often cut into small cubes and cooked with yam and coconut milk ( santan) to make a sweet dessert called bubur caca. A favourite way of cooking sweet potato is deep frying slices of sweet potato in batter, and served as a tea-time snack. In houses, sweet potatoes are usually boiled. The leaves of sweet potatoes are usually stir-fried with only garlic or with sambal belacan and dried shrimp by the Malaysian Chinese.
* In India, in some regions fasts of religious nature are an occasion for a change in normal diet, and a total absence from cooking or eating is held as elective while a normal diet for a fasting day is a light feast consisting of different foods from usual, amongst which sweet potato is one of the prime sources of sustainance. Sweet potato is eaten otherwise too, and a popular variety of preparation in most parts is roasted slow over kitchen coals at night and eaten with some dressing - primarily salt, possibly yogurt - while the easier way in south is simply boiling or pressure cooking before peeling, cubing and seasoning for a vegetable dish as part of the meal. Usually the preparations for sweet potato are similar to the blander ones for potato, while the sharper versions - with more green chilly or red pepper - are reserved for potato.

[ edit] North America

* Candied sweet potatoes are a side dish consisting mainly of sweet potatoes prepared with brown sugar, marshmallows, maple syrup, molasses, orange juice, marron glacé , or other sweet ingredients. Often served in America on Thanksgiving, this dish represents traditional American cooking and of that prepared with the indigenous peoples of the Americas when European American settlers first arrived.
* Sweet potato pie is also a traditional favourite dish in southern U.S. cuisine.
* Sweet potatoes slices are fried in bacon drippings and eaten with the bacon on toast. This is a traditional autumn breakfast food in rural Kentucky.
* Sweet potato fries or chips are another common preparation, and are made by julienning and deep frying sweet potatoes, in the fashion of French fried potatoes.
* Baked sweet potatoes are sometimes offered in restaurants as an alternative to baked potatoes. They are often topped with brown sugar and butter.
* In Dominican Republic, sweet potato is enjoyed for breakfast.
* Sweet potato butter can be cooked into a gourmet spread.
Source: Wikipedia
http: / / en.wikipedia.org/ wiki/ Sweet_potato