Sweet potato

The sweet potato (Ipomoea batatas) is a fleshy root that is eaten as a vegetable. It is a member of the morning glory family, Convolvulaceae. It originated in Central and South America, but the vegetable made its way to other continents long before European explorers arrived in the New World. It grows best in warm temperatures. In the United States, commercial production is primarily concentrated in North Carolina and Louisiana. This important food crop is harvested for both its fleshy roots and its shoots in tropical and subtropical countries. The plant spreads across the ground as a vine, and nodes on the plant root into the soil. Most sweet potatoes are orange. Although they are often called yams, they belong to a different plant family than true yams.

Brief History

The sweet potato has long been a staple of cuisines in Asia and the Americas. It is popular in Polynesia, where the warm climate provides ideal growing conditions. The plant has its roots in the Americas though. Archaeological evidence of cultivation and consumption in Peru dates to about 2500 BCE. Researchers analyzed DNA from the vegetable around the world and found that all varieties are genetic descendants of plants from Ecuador and Peru.

The oldest samples from Polynesia date from about 1000 CE. Researchers believe this is proof that Polynesian people traveled across the Pacific Ocean to South America centuries before Christopher Columbus arrived in the New World in the fifteenth century. The sweet potato was the primary food of the Maoris of New Zealand when British explorer Captain James Cook arrived in 1769. The sweet potato arrived in Europe with Columbus, who collected plants on his fourth visit to the Americas.

American colonists later relied on sweet potatoes to survive. The vegetable sustained the population through the Revolutionary War, the Civil War, and the Great Depression.

Overview

Several varieties of sweet potatoes are commercially grown in the southern United States. These include Beauregard, Bush Porto Rico, Centennial, Georgia Jet, Jewell, Sumor, and Vardaman. Most varieties have orange flesh. The skin may be yellow, copper, orange, or light purple. Days to harvest for most varieties range from 100 to 110 days.

Sweet potato plants are grown from small plants called slips. Slips may be started in a hotbed in light soil or sand, about an inch apart, until they sprout. After about six weeks, plants should be six to eight inches tall. They may be cut from the roots, which may continue to produce slips, or the roots may be lifted completely for transplant.

Slips should be spaced twelve to eighteen inches apart in garden beds. The plants grow best on wide, raised ridges about eight inches high because they drain better and the plants dry quickly in the spring. Rows should be spaced three to four feet apart to give the vines room to spread.

Plants are harvested in the fall, around the time when the first frost is expected. Harvesters dig into the side of the ridges carefully with a spading fork or shovel to expose the roots and work toward the center. The soil must be moved carefully to avoid damaging the roots, which should be left on top of the soil for two to three hours to dry. They should be cured in a warm room, ideally at 85 degrees Fahrenheit with 85 percent humidity, for ten to fourteen days. Once cured, they should be stored at 55 degrees Fahrenheit. If frost hits the plants before harvest, the vines must be cut away immediately to keep the roots from rotting. Sweet potato plants may be subject to some diseases, such as scurf. Mice may dig into the mounds and eat the roots. Roots may not become plump if plants do not get enough rain during the growing season or if the soil does not drain well. Rain in the final weeks of growth may cause the roots to split.

In some areas, the roots and plants are often fed to livestock. In much of the United States, and in many parts of the world, the sweet potato is a food product. It may be prepared and served many ways. Sweet potatoes can be baked, grilled, or microwaved whole. They may be peeled and sliced or diced, and boiled, broiled, sautéed, or steamed. The vegetable may be mashed or pureed as well. Today, sweet potatoes are increasingly served as French fries. The vegetable may also be grated or sliced and eaten raw in salads and slaws. Sweet potatoes are often featured in appetizers, entrees, and side dishes. The vegetable is also used in sweet baked goods, such as pies and cookies. In some cases, the leaves of the plant are consumed. They may be baked, boiled, or steamed.

Despite the sweet taste, these root vegetables are low in calories. One whole sweet potato, baked in the skin, has just one hundred calories and no fat. They are suitable for consumption by individuals with diabetes and by people who are hoping to lose weight. The twenty-three grams of carbohydrates in a sweet potato are complex carbohydrates, and sweet potatoes have a low glycemic index, which means they release sugar slowly.

One sweet potato contains 120 percent of the daily recommended intake of vitamin A, which is an antioxidant. Sweet potatoes are also high in vitamin B5 and vitamin B6, thiamin, niacin, riboflavin, and carotenoids. They are also an excellent source of manganese, which helps the body maintain healthy blood sugar levels. Some studies indicate certain varieties of sweet potatoes may eventually be useful in controlling blood glucose. The vegetable also offers anti-inflammatory benefits, and the magnesium it contains relieves stress and promotes nerve health. The dietary fiber in sweet potatoes helps maintain a healthy digestive system.

Sweet potatoes of different colors offer some different nutritional benefits. Orange sweet potatoes have anti-carcinogenic properties, though research indicates the purple vegetables may offer even greater protection.

People who often eat sweet potatoes or any other foods high in vitamin A may develop an orange tinge to their skin and nails because the body stores excess amounts of the nutrient. The effect should go away if the individual cuts back on foods high in vitamin A. People with kidney stones may want to eat sweet potatoes in moderation. The vegetable contains oxalate, which can contribute to the formation of calcium-oxalate stones.

Bibliography

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