How to Cook Purple Yams: Baked, Boiled or Roasted

The purple yams you find in the grocery store are actually from the family of sweet potatoes — the orange variety — rather than yams. Purple sweet potatoes make a delicious side dish that's full of nutrients and health benefits.

Simple to prepare, purple yams can turn ordinary recipes such as pies, cakes and soups into something bright and memorable. You can cook purple yams with moderate heat in the oven to make them pleasantly moist before incorporating them into your favorite dishes.

All sweet potatoes, including purple yams, come from the morning glory family, per the Harvard T.H. Chan School of Public Health. They differ from yams, which are edible, starchy tubers.

Stokes purple sweet potatoes are a variety of purple-skinned and purple-fleshed potatoes originating in North Carolina. They are dense and tend to be slightly drier in texture than orange types of sweet potato. You may also find other varieties of purple sweet potatoes. These include the following:

• Okinawan, which is beige on the outside and lavender-colored on the inside. They have a creamy texture and are a standard ingredient in the Hawaiian pie called Haupia. Use them in this Purple Sweet Potato Hummus recipe.
• Murasaki sweet potatoes, or Japanese sweet potatoes, are white on the inside but have purple skin.
• Ube is, in fact, a yam that's purple inside and brown on the outside. Due to their naturally sweet flavor, they are a common ingredient in Asian desserts.

All of these varieties can be baked, boiled or steamed the same way. When the potatoes are soft, split them open and top with a small dollop of butter and seasoning. You may also enjoy them with an added squeeze of lime juice and chopped fresh cilantro.

When you use purple sweet potatoes in baked goods, such as quick bread or cakes, the anthocyanins responsible for their color may react with baking soda and baking powder, giving them a blue or green hue. Sometimes, these antioxidants can turn your baked goods red, according to Maryland Grows.

If you decide to boil purple sweet potatoes, try a Spicy Purple Potato Salad recipe for a delicious and nutritious meal.

There are several ways to cook purple yams, and baking them is a popular one. That's because it's a no-fuss method that requires little effort — all you have to do is set the temperature on the oven, put the yams in and take them out when they're done.

Here's how to do it:

1. Set your oven to 350 degrees Fahrenheit.
2. Poke each purple yam with a fork to pierce the skin and prevent it from exploding in your oven.
3. Wrap the yams in aluminum foil and place them on a baking sheet.
4. Place the purple yams in your oven on the center rack. Cook for 90 to 120 minutes, or until the yams are soft when pierced with a fork.
5. Remove the yams from the oven and let cool.

Boiling purple yams is yet another simple way to prepare them. Boiling them in water will help the yams turn out soft, and it takes less time than baking. Just keep in mind that boiling vegetables may result in some nutrient loss.

1. Place purple yams in a large pot and cover completely with water.
2. Turn the heat on your stove to high and bring the water to a boil.
   
3. Cover the pot and lower the heat to medium. Allow the yams to simmer for at least 40 minutes.
4. Check for doneness by inserting a fork into a yam. If it is fully cooked, it will easily pierce the yam.
5. Remove the yams from the heat when they're tender, and allow them to cool before peeling.

There's a slight difference between roasting and baking purple yams. When roasting, you'll cook the yams in the oven at a higher temperature, which will make them brown faster.

1. Preheat your oven to 425 degrees Fahrenheit.
2. Meanwhile, dice the purple yams into 1-inch cubes and toss with olive oil in a large bowl.
3. Arrange the diced yams on a baking sheet and place in the oven on the middle rack. Roast for 45 minutes, or until purple yams are tender, flipping once or twice during cooking to promote even browning.
4. Remove the baking sheet from the oven and add your salt, pepper and other seasonings as desired before serving.

There's great nutritional value in purple sweet potatoes. Specifically, they contain a unique phytochemical known as anthocyanin, according to the Harvard T.H. Chan School of Pubilc Health.

The phenolic compounds, flavonoids and anthocyanins in purple sweet potatoes are tied to anti-inflammatory and anti-cancer effects, per an October 2015 review in ‌BioMed Research International‌. Anthocyanins also boast anti-diabetic and antimicrobial properties.

A cup of cooked purple sweet potato contains about 500 milligrams of anthocyanins — close to the same amount in a cup of blueberries, according to the University of California.

Frieda's — a major brand of Stokes sweet potatoes — notes that a 3.8-ounce serving provides 130 calories, 28 grams of carbohydrates, and 2 grams of protein. You'll also get 2 percent of the daily value for vitamin A and 20 percent of the daily value for vitamin C as well as some iron and calcium.

Compare this to an average sweet potato that, according to the USDA, boasts 127 calories, 23.5 grams of carbohydrates, 2.3 grams of protein, and 3 grams of fat in a 4.1-ounce serving. These starches do have a similar nutritional value, but sweet potatoes are higher in antioxidants and other bioactive compounds.