Sweet potatoes are tubers, distantly related to potatoes, and are native to South America. They are often confusing to consumers since many sweet potatoes are labeled as yams in the US. In fact true yams, first grown in Africa, are much larger, starchier and far less sweet. Sweet potatoes, on the other hand, can be very sweet, but sweetness depends upon the variety.
In the US we commonly see certain sweet potatoes marked as sweet potatoes because they have light tan skin, and a yellow flesh when baked. These are actually the least sweet of the sweet potatoes. They have a mild and creamy flavor, and make an excellent change from regular baking potatoes like russets.
When we look for sweet potatoes for recipes like sweet potato pie, we normally look for dark brown, reddish or even slightly purple exterior skin. The interior of such sweet potatoes is often a deep orange and is very sweet. It needs little additional sugar, and makes a fantastic treat simply baked and garnished with a little nutmeg and a pat of butter.
Alternately, some enjoy using these darker sweet potatoes, often marketed as garnet or jewel yams, to make sweet potato casserole, mashed sweet potatoes, or to make delectable sweet potato french fries or chips. Japanese vegetarian tempura often batters and fries sweet potatoes, and they can be a delicious contrast to the tempura sauce in which they are dipped.
Sweet potatoes pack a nutritional punch that is not to be missed. As well, the garnet or jewel variety is excellent for dieters who want to fulfill their sweet tooth needs in a healthy fashion. A medium baked sweet potato, when not soaked in butter, has a modest 117 calories. It includes 3.4 grams of dietary fiber, 28 milligrams of vitamin C, 25.7 milligrams of folic acid, and 396 milligrams of potassium. As orange-fleshed root vegetables, sweet potatoes are also chock-full of vitamin A, containing over 200% of the US recommended daily allowance for the vitamin. Vitamin A in vegetable forms, and not derived from fish oils or liver is quite safe to eat in this amount.
Sweet potatoes are often associated with the autumn, because in the US, this is when they are generally harvested. A plethora of comfort food recipes incorporate the sweet potato. However, most sweet potatoes today are not grown in the US, but rather in China. Though it may be unusual to associate the sweet potato with Asian foods aside from tempura, it is actually a primary ingredient in many Asian dishes.