I’m often asked about the difference between sweet potatoes and yams. The sweet potato is not a potato or even a distant cousin. Potatoes are tubers; sweet potatoes are roots.
True yams (from tropical and subtropical regions of the world) contain more starch and less sugar than sweet potatoes — and they must be cooked before eating. African slaves in the South called the sweet potato “nyami” because it reminded them of the starchy, edible tuber of that name that grew in their homeland. The Senegalese word “nyami” was eventually shortened to “yam.”
When the orange-fleshed, Puerto Rican variety of sweet potatoes was adopted by Louisiana producers and shippers, they called them “yams” to distinguish them from the white-fleshed sweet potatoes grown in other parts of the country. The yam reference became the trademark for the Louisiana-grown sweet potato, and refers to sweet potatoes that are grown in Louisiana.
There is a difference between sweet potatoes grown in northern states and those grown in Louisiana. Sweet potatoes produced in the northern states mostly are “firm” and tend to be drier and more mealy with yellow flesh. Folks in Louisiana enjoy the second type, “soft,” which is higher in natural sugar. Louisiana sweet potatoes are moister, and have a bright-orange flesh color. Most often, it is the “soft” type that is referred to as a yam.
Sweet potatoes are stored in temperature- and humidity-controlled warehouses that extend their shelf life for the entire year. So the “season” for fresh yams is 12 months. Canned yams also are available year-round.
Here’s some great information about the health benefits of sweet potatoes, and how to select, store and prepare them:
• Sweet potatoes provide twice the recommended daily allowance of vitamin A and more than one-third of the daily requirements of vitamin C.
•Sweet potatoes are an important source of beta-carotene, vitamin B-6, iron, potassium and fiber.
• Studies consistently have shown that a high intake of beta-carotene-rich vegetables and fruits, like sweet potatoes, can significantly reduce the risks for certain types of cancer.
• Sweet potatoes contain virtually no fat or sodium.
This recipe showcases the flavors of the sweet potato in a spicy, coconut-milk broth.
Vietnamese sweet potato and pork soup
1 tablespoon canola oil
1 pound ground pork
1 small onion, finely chopped (about 1/2 cup)
1/4 cup chopped fresh basil, divided
1 (3-inch) piece lemongrass or zest of 1 lemon
3 cloves garlic, minced
1 jalapeno pepper, chopped
2 teaspoons grated fresh ginger
2 teaspoons ground cumin
1 1/2 teaspoons ground cardamom
1 teaspoon salt
1 teaspoon ground black pepper
1/4 teaspoon ground nutmeg
2 sweet potatoes, peeled and cut into 1/2-inch cubes (about 2 cups)
1 quart chicken stock
1 (13.5-ounce) can light coconut milk
1 tablespoon soy sauce
Chopped fresh cilantro, basil or jalapeno pepper slices for garnish
In a large stockpot, heat oil over medium heat. Add pork, onion, two tablespoons basil, lemongrass or lemon zest, garlic, jalapeno, ginger, cumin, cardamom, salt, pepper and nutmeg. Cook until pork is browned and onion is soft, about 10 minutes.
Add sweet potatoes, chicken stock and coconut milk. Bring to a boil and then reduce heat to a simmer. Cover and cook until sweet potatoes are tender, about 20 minutes. Uncover, remove lemongrass (if used) and stir in soy sauce. Garnish with remaining cilantro, basil and jalapeno, if desired.
Medearis is the author of seven cookbooks. Her website is www.divapro.com.