Sweet potatoes are not really potatoes, nor are they yams. This tuber,
like its relative the morning glory, is a Native American vegetable.
Grown in central and tropical America long before the arrival of
Columbus and the other European explorers, it was a diet staple, along
with corn and pumpkin. The explorers evidently liked the sweet taste
and carried it home with them at the end of their travels, where it was
planted with some success. In America, it was quickly adopted by
colonial gardeners and, like pumpkins, was one of the foods that helped
sustain life during the first long, cold winters when other crops had
failed or performed badly in the unfamiliar soil.
Yams on the other hands are an African vegetable, transplanted to South
America and the Caribbean, but rarely available in the United States,
outside of certain ethnic markets. The confusion comes from
transplanted Africans referring to the sweet potato by the same name as
the more familiar starchy root vegetable from their homeland, although
they have nothing in common as far as taste is concerned.
Sweet potatoes are widely eaten in the southern part of the United
States and are usually included in holiday menus everywhere else –
often buried beneath a thick layer of marshmallow. They deserve better.
There are several varieties of sweet potato. The very familiar moist
potato with a deep russet colored skin and dark orange flesh is the
variety most frequently eaten in the South and the one often mistakenly
called a yam. There is also a sweet potato with a drier, yellower
flesh. These are delicious baked and used in gratins and casseroles,
while the more orange variety takes well to sweeter preparations,
including certain desserts and pies, although the two kinds are
basically interchangeable. In additional to these two most commonly
available, there are other varieties, including one with a purplish
skin and a pale grayish blue flesh. Most of these are direr fleshed
than the deep orange variety.
The starch in sweet potatoes is converted to sugar as it matures, which
accounts for the sweet flavor. In fact, some growers cure sweet
potatoes by heating them to 85 F for several days before shipping them.
This may stabilize the sugar and seems to increase the storage time.
Because most people associate sweet potatoes with ultra sugary
preparations, they are often neglected in everyday cooking. If you have
never had a sweet potato plainly baked, opened, fluffed, and served
with nothing more than a little butter, salt and pepper, you have
missed a major treat. Sweet potatoes can be prepared in many of the
ways white potatoes are served. They can be boiled, baked, fried,
roasted, mashed and gratineed and made into casseroles, salads and
soups as well as sweetened dishes.
Not only are sweet potatoes versatile, they are extremely nutritious.
Their vegetable nutrients includes low calorie, less than an equal sized white potato, low fat,
and cholesterol free, relatively high in carbohydrates, and exploding
with beta carotene. The deeper orange the flesh, the more beta carotene
it contains. Given the most recent research into the benefits of food
rich in beta carotene, sweet potatoes could be very helpful in
preventing certain types of cancer. They also provide moderate amounts
of fiber nutrients, vitamin C and potassium.