The Sweet Potato: Gastronomical Uses and Nutrition
This tuber that’s native to the tropical Americas has certainly had a busy itinerary since the 16th century when Spanish and Portuguese traders exported sweet potato plants to the Philippines, Africa, Indonesia and the Indian subcontinent. From there the popular vegetable found its way to Europe and then to what would become the United States, in the latter part of the 16th century; Its cultivation was found to be most prolific in the Southern part of the country, mainly because of the long, warm growing season.
The first recorded mention of the sweet potato was in the journal of Columbus and his fourth voyage of 1502, in the West Indies. Since then evidence has been discovered in Peruvian caves which proves that the tuber has been eaten since prehistoric times. The name sweet potato (botanical name, Ipomoea batatas) suggests that this tuber vegetable is a close relation to the potato (Solanum tuberosum). In fact sweet potato is a member of the morning glory genus, and part of the Convolvulaceae botanical family.
In the USA where sweet potatoes are very popular there are two basic varieties, both of which have red skins. One variety has orange-red or brown moist flesh when cooked. It is often labeled as yam or Louisiana yam. However, true yams are starchier and don’t have the sweet flavor of the sweet potato. Moreover, yams are the edible roots of the dioscorea genus, which originate from Asia. The other variety, which requires longer cooking, has pale white, mealy, drier flesh and is usually labeled as sweet potato. Both variety’s are from the same botanical family, so if you think you are buying yams they may actually be sweet potatoes.
Worldwide there are over 400 varieties of sweet potato. Boniato, also known as batata, is one of the best known varieties, particularly in South America and Asia. Boniato isn’t as sweet as other varieties, but it has a light, slightly spicy, aromatic flavor. A Japanese variety, known as Okinawan has reddish-brown skin and is sweet and moist with a nutty flavor, similar to roasted chestnut.
Sweet potatoes are in season during the late winter months and you could say they have one big advantage over potatoes. They can be used for sweet and savory dishes. Some Creole puddings include sweet potato, there is even apple pie with sweet potato. There is also the sickly, holiday favorite combination of melted marsh mellows and sweet potato. For some reason many sweet potato recipes seem to involve the addition of sugar or honey. Personally, I think the natural sweetness of this tuber is enough without adding extra sweetness. Often all a baked or mashed sweet potato needs is a knob of butter. Although this tuber’s sweet flavor does combine particulary well with the flavors of cinnamon, nutmeg, coconut, chili, almonds, pecans, lime juice, orange juice and cilantro. Sweet potato is also very good simply cut julienne or diced, then sautéed in butter with garlic. Use it as a side dish for roast pork, ham, gammon or game meats. Sweet potatoes can be used to replace potatoes in any recipe, although the white, mealy varieties do not mash well. You will also want to increase the cooking time, depending on the variety.
Buying and Storing: Look for sweet potatoes without cracks, bruises or soft spots. This tuber is more perishable than the potato and like the potato, it is best not refrigerate as they tend to lose flavor. Stored in a cool dry place, where air can circulate, sweet potatoes will last for about one week.
Nutrition: As with any orange fleshed vegetable, sweet potato contains vitamin A or beta-carotene. In fact these tubers contain more of these antioxidant packed flavonoids than any other root vegetable, making them an excellent food source for cardiovascular health. Moreover, the deeper the orange color, the more vitamin A. Purple fleshed sweet potatoes, such as Okinawan, contain the group of flavonoids known as anthocyanins. The antioxidant activity of anthocyanins help neutralize harmful free radicals which cause cellular damage that leads to chronic diseases such as cancer. Anthocyanins are anti-inflammatory and antimicrobial.
Sweet potatoes are also a good source of potassium, vitamin C and contain riboflavin, pantothenic acid or vitamin B5, folic acid and copper. Sweet potatoes and regular potatoes contain about the same amount of carbohydrate. Sweet potatoes contain more starch than white potatoes and therefore more calories. One hundred grams of regular white potatoes has about 79 calories, as compared with the same amount of sweet potatoes which has 105 calories.