This is an updated version of my original post on “Sweet Potatoes 101 – The Basics.”  The information has been expanded and new sections added for more comprehensive information. Hopefully, any questions you have about sweet potatoes will be answered below.

Enjoy!
Judi

 

Sweet Potatoes 101 – The Basics (UPDATE)

About Sweet Potatoes
Sweet potatoes are root vegetables that belong to the morning glory family. They are not the same thing as yams, and are in a different plant family than yams and even common potatoes. Sweet potatoes are sometimes labeled as “yams” in American grocery stores. However, true yams are not commonly found in the United States, except perhaps in international markets.

There are around 400 varieties of sweet potatoes, with skin colors ranging from almost white to yellow, red, purple, and brown. The flesh color ranges from white to yellow, orange, orange-red, and purple. Sometimes sweet potatoes are shaped like a common potato, being short and stout with rounded ends, while other may be longer with tapered ends. Sweet potatoes can be classified as either “firm” or “soft.” When cooked, those in the “firm” category remain firm. Those classified as “soft” become soft and moist when cooked. The “soft” varieties are the variety most likely to be labeled as “yams” in the United States.

Sweet potatoes are native to Central and South America. They are among the oldest vegetables known to man and have been eaten since prehistoric times. There is evidence in ancient Peruvian caves dating sweet potatoes back 10,000 years.

Christopher Columbus brought sweet potatoes to Europe after visiting the New World in 1492. By the 16^th century, they were taken to the Philippines by Spanish explorers and to Africa, India, Indonesia, and southern Asia by the Portuguese. Around this time, sweet potatoes were being grown in the southern United States, where they are still among the traditional cuisine. Currently in the United States, over half of all commercially produced sweet potatoes are grown in the southern states, especially in North Carolina.

Nutrition and Health Benefits
Sweet potatoes are one of the most abundant sources of the antioxidant beta-carotene, a precursor to Vitamin A in the body. They are also high in Vitamin C, manganese, magnesium, copper, pantothenic acid, Vitamin B6, potassium, fiber, niacin, Vitamin B1, Vitamin B2, and phosphorus.

In addition to these vitamins and minerals, sweet potatoes are rich in unique phytonutrients that have strong antioxidant properties, helping us to ward off disease. This is especially the case with the purple and orange flesh varieties.

Beta-Carotene and Eye Health. Sweet potatoes are highly prized for their orange-colored carotenoid pigments. In many underdeveloped regions of the world, sweet potatoes are used as an effective way of providing people with their daily Vitamin A needs. This is important because it helps to prevent blindness due to xerophthalmia, the leading cause of blindness among children in the world. Some studies have found that sweet potatoes were a better source of bioavailable beta-carotene than green leafy vegetables.

Cancer Protection. Beta-carotene is one of many antioxidants found in sweet potatoes that may help to reduce the risk of cancer, including bladder, colon, stomach and breast cancers. Purple sweet potatoes are particularly high in anthocyanins, which appear to have an enhanced protective effect, although all sweet potatoes are protective.

Cardiovascular Disease Protection. Antioxidants also protect us from oxidative stress and atherosclerosis that leads to cardiovascular disease. Soluble fiber, like that found in sweet potatoes, helps to regulate blood cholesterol levels. Being rich in potassium and magnesium, sweet potatoes have been shown to help regulate blood pressure, thereby reducing the risk for cardiovascular disease and associated conditions. With all factors considered, sweet potatoes provide a variety of nutrients that can work together to lower our risk for cardiovascular disease and related problems.

Healthy Skin and Hair. Carotenoids, like those found in sweet potatoes have been found to promote healthy skin and hair. Sweet potatoes are also high in Vitamins C and E. Studies have shown that Vitamin E has the potential of significantly increasing hair numbers in people suffering from hair loss. This effect was due to the antioxidant properties reducing oxidative stress, which is a major cause of hair loss.

Vitamin C has also been shown to be effective in the treatment of hyperpigmentation of skin. It neutralizes the oxidative stress caused by UV light. Vitamins C and E combined have been found to significantly reduce the risk of skin cancer in individuals. It is well established that Vitamin C is used in the making of collagen, a structural protein of the skin, which is vital in the management of healthy skin. The vitamin has been shown to help improve skin conditions such as acne, and promote the healing of wounds. Vitamin A has been an effective treatment for sun-damaged skin, and also skin cancer. Like Vitamin C, Vitamin A also stimulates the production of collagen, making it helpful in slowing the rate of cell aging and inhibiting hyperpigmentation of aging skin.

With sweet potatoes having high levels of Vitamins A (in the form of carotenoids), C, and E, the vegetable can play an important role in the repair and management of healthy skin and hair.

Fiber and Gut Health: The antioxidants combined with the soluble and insoluble fibers in sweet potatoes make them an excellent food for supporting the health of our gastrointestinal tracts. Soluble fiber absorbs water and softens stool. Insoluble fiber provides bulk and promotes movement of the contents of the GI tract. Studies have also found that antioxidants can help promote the growth of healthy bacteria in the gut, which further supports the health of the GI tract, and lowers the risk of conditions like irritable bowel syndrome. Some of each type of fiber provides food for the bacteria that live in the colon, creating short-chain fatty acids that fuel the cells lining the intestines keeping them healthy. Fiber-rich diets have been shown to lower the risk of colon cancer.

Cooking Method Makes a Difference. Some people are concerned about the sugar content of sweet potatoes. Yes, they do contain some sugar. However, they are high in fiber, which is very effective in stabilizing blood sugar. Interestingly, how a sweet potato is cooked affects the glycemic index of the vegetable.

Boiling with the skin intact appears to retain most of the antioxidants in sweet potatoes, when compared to roasting and steaming. The skin has nearly ten times the antioxidants as the flesh, which are drastically reduced when the potatoes are baked. The glycemic index of boiled sweet potatoes is much lower than that of baked ones. Steaming also seems to be a good way to preserve the nutrients in sweet potatoes, following second to boiling with the peel on.

A little fat will do. To get the most benefit from the beta-carotene content of sweet potatoes, it is helpful to include some fat with the meal, since sweet potatoes contain very little fat. Beta-carotene is a fat-soluble substance, so fat is needed for its best absorption. Note, that just a small amount of a fat-containing food will do. There is NO need to slather your sweet potato with butter. A mere 3 to 5 grams of fat in a meal can be enough to aid in the absorption of the beta-carotene in sweet potatoes. For instance, 1 tablespoon of extra virgin olive oil has 14 grams of fat. Doing the math, a mere teaspoon of oil (providing 3-1/2 grams of total fat) per meal is enough fat to do the job. Or, instead of olive oil, only 3-1/2 walnut HALVES (that’s less than two whole walnuts) could also do the trick, providing about 4-1/2 grams of total fat. So, a little fat will go a long way in helping us to absorb the beta-carotene in sweet potatoes!

How to Select Sweet Potatoes
Choose sweet potatoes that are firm and without cracks, bruises or soft spots. Small to medium size sweet potatoes will tend to be sweet and creamy, whereas larger ones tend to be starchier.

How to Store Sweet Potatoes
Store sweet potatoes in a cool, dark, well ventilated place away from a heat source. Ideally, they should be stored below 60F (but above 40F, refrigerator temperature), which would be equivalent to a root cellar. Since most of us don’t have root cellars, a cool, well ventilated place will usually suffice. Refrigeration is not recommended as it will alter the flavor. Also, it is best to store sweet potatoes loosely, not in plastic bags, which could invite mold.

How to Prepare Sweet Potatoes
Sweet potatoes can be baked, steamed, boiled, roasted, microwaved, dried, juiced, made into soups, added to casseroles, baked into breads, muffins, cakes, cookies, and pies, added to pancakes, and even eaten raw. How you use sweet potatoes is only limited to your imagination! Below are details of just a few ways that sweet potatoes could be cooked.

Wash the sweet potatoes and peel them, if desired. The skin is edible, so it is not mandatory to peel them. Sweet potato flesh will darken after being cut or peeled, so use them immediately after cutting into them. If needed, they can be submerged in a bowl of cold water to prevent oxidation, until you are ready to cook them.

To minimize nutrient loss, it is helpful to cook sweet potatoes with the peel on. Then remove the peel, if desired, after they are cooked. The peel is edible and nutritious. However, they may be coated with wax or even dyed if purchased commercially. In this case it may be wise to remove the peel before eating your sweet potatoes. Opting for organic sweet potatoes would avoid those potential issues.

Steaming Sweet Potatoes. Steaming sweet potatoes seems to be a valuable way to cook them while preserving nutrients. Steaming also allows them to cook quickly, while keeping the glycemic index low. Steam 1/2-inch sweet potato slices for 7 minutes, then top them with a small amount of a fat-containing food, like a couple chopped walnuts, to help utilize the beta-carotene in them.

Baking Whole Sweet Potatoes. Preheat the oven to 375°F. Scrub the potatoes and place them on a clean, dry baking sheet on the rack in the middle of the preheated oven. Bake the sweet potatoes for about 1 hour (or more depending on their size), until they are fork-tender. Remove the potatoes from the oven and allow them to cool.

Boiling Whole Sweet Potatoes. Boiling whole sweet potatoes is very easy and takes little effort. Wash the potatoes well in cool water. Do not peel them. Place them in a large pot and cover them with water. Place a lid on the pot and bring everything to boil. Turn the heat down to about medium, cock the lid and allow them to boil gently for anywhere from 30 to 60 minutes, until a sharp knife can easily pierce the potatoes. Drain the water and allow them to cool enough to be handled. Once cooled, the peel can very easily be removed, if desired.

Cooked sweet potatoes should be stored in a covered container in the refrigerator. Use them within three to five days.

How to Preserve Sweet Potatoes
Sweet potatoes can be dehydrated, frozen or canned.

Dehydrating Sweet Potatoes. Sweet potatoes should be cooked first before being dehydrated. They may be either boiled, steamed or roasted. Wash the sweet potatoes and leave the peel on (if roasting or boiling the potatoes). Personally, I have found the best results for dehydrating sweet potatoes when they were roasted first. Roast them (unpeeled, washed, and with no added oil or spices on them) on a rimmed baking sheet at 375°F until they are fork-tender, about 1 hour or more, depending on the size. Remove from the oven and allow them to cool so they can be handled. Remove the peel and slice them about 1/4 to 3/8-inch thick. Place them in a single layer on your dehydrator mesh tray, making sure the slices do not touch each other. Follow your dehydrator manufacturer’s instructions for time and temperature for drying your sweet potatoes. When finished, store them in air-tight containers.

For a demonstration on dehydrating sweet potatoes with this method, see my video at https://youtu.be/SmalFyoROgU

Freezing Sweet Potatoes. Sweet potatoes can be frozen in a number of ways depending on how they will be used later. Here are directions for various ways to freeze sweet potatoes:

Freezing Boiled Sliced or Diced Sweet Potatoes. Bring a large pot of water to boil. Meanwhile, scrub the sweet potatoes and peel them*. Slice or dice the potatoes as desired. Add the potato pieces to the boiling water and cook for about 10 minutes, or until they just begin to get tender, but are still quite firm. Remove the cooked potatoes and let them stand at room temperature until they are cooled.

Transfer the prepared sweet potato pieces to freezer containers or bags and remove as much air as possible. Label with the current date and place them in the freezer. Alternatively, to keep the potato pieces from freezing in one big lump, you can place the prepared pieces in a single layer on a parchment paper-lined baking sheet or tray. Place the tray in the freezer. When the pieces are frozen, transfer them to a freezer container or bag, label it with the current date, then return them to the freezer. For best quality, use the potato pieces within 12 months.

* Sweet potatoes may also be boiled whole, with the skin intact. Simply scrub them and submerge them in a pot of water. Bring the water to boil, then reduce heat and simmer until the potatoes can easily be pierced with a sharp knife. Remove them from the hot water and allow them to cool. Remove the skins, then slice them as desired, and proceed as detailed above.

Freezing Whole Baked Sweet Potatoes. Preheat the oven to 375°F. Scrub the potatoes and place them (unpeeled) on a clean, dry baking sheet on the rack in the middle of the preheated oven. Bake the sweet potatoes for about 1 hour (or more depending on their size), until they are fork-tender. Remove the potatoes from the oven and allow them to cool. Wrap the cooled sweet potatoes in foil and transfer them to freezer bags to freeze whole. Or, freeze the baked potatoes individually on a baking sheet. Once frozen, transfer them to freezer bags and return them to the freezer. For best quality, use them within 12 months.

To reheat whole baked sweet potatoes, remove the foil (if foil was used) and rewrap them in a new piece of foil. Bake at 350°F for about 25 to 35 minutes.

Freezing Mashed Sweet Potatoes. Bake the whole sweet potatoes as directed above. Slip the skins off the cooled potatoes, and put the flesh in a large bowl or food processor. Process until smooth. Add a tablespoon of lemon juice for each pint (2 cups) of mashed sweet potatoes, if desired. Lemon juice helps to prevent browning, but it is not absolutely necessary. The mashed sweet potatoes can be added to casseroles, breads, puddings, cakes, pies, and cookies.

Fresh vs Frozen vs Canned Sweet Potatoes
Sweet potatoes can be found fresh, frozen (in some grocery stores), and canned. Fresh sweet potatoes offer the most versatility, but frozen ones (if you can find them) are a great convenience. Frozen sweet potatoes can be used for just about any cooking application and will save time in the kitchen. Canned sweet potatoes are a nice third option, but are usually packed with added sugars and possibly other ingredients. They may be convenient and time-saving, depending upon your intended use of them. They are a handy kitchen staple to have in the cupboard in case of emergencies or when time is running short.

Quick Ideas and Tips for Using Sweet Potatoes
* Try potato pancakes with a mix of white and sweet potatoes. Top with apple cranberry chutney.

* If you have leftover mashed sweet potatoes, add them to your usual pancake mix for breakfast the next day.

* Raw sweet potatoes will turn dark shortly after being peeled, so it’s best to peel them right before using them. If you need to peel them in advance, place them in a bowl of cool water to keep them from turning dark.

* Make a simple dessert with puréed cooked sweet potatoes and bananas, maple syrup, and a dash of cinnamon or allspice. Top with chopped walnuts.

* If you’re low on sweet potatoes and need them for a recipe, possible substitutes include carrots, pumpkin, and winter squash (such as butternut, buttercup, or kabocha).

* It’s best not to keep raw sweet potatoes in the refrigerator. When they get too cold, it can change how their starches break down, making them tougher to cook and eat. According to the USDA, the ideal temperature for keeping sweet potatoes is around 60°F.

* For a quick meal, slice a cooked whole sweet potato in half lengthwise. Top with leftover chili and grated cheese, or black beans and salsa, or baked beans, or scrambled eggs.

* One pound of sweet potatoes will be about 4 cups chopped or sliced.

* Try adding mashed cooked sweet potatoes to baked goods for added moisture without adding extra fat.

* Try sautéed, spiralized sweet potatoes. Top it with your favorite sauce or sweet potato seasonings.

* Try roasted Hasselback sweet potatoes; drizzle with maple syrup and a sprinkle of thyme.

Herbs and Spices That Go Well with Sweet Potatoes
Allspice, basil, bay leaf, cardamom, cayenne, chili pepper flakes, chili powder, cilantro, cinnamon, cloves, coriander, cumin, curry powder (and spices), garam masala, lemongrass, marjoram, mustard (seeds, powder), nutmeg, oregano, paprika, parsley, pepper, rosemary, sage, salt, savory, thyme, turmeric, vanilla

Foods That Go Well with Sweet Potatoes
Proteins, Legumes, Nuts, Seeds: Almonds, beans (in general, esp. black, green beans), chickpeas, duck, eggs, ham, lentils, nuts and nut butters (in general), peanuts, pecans, pine nuts, poppy seeds, pork, poultry, pumpkin seeds, sesame seeds, sunflower seeds, tempeh, tofu, walnuts

Vegetables: Arugula, bell peppers, carrots, cauliflower, celery, chard (Swiss), chiles, fennel, garlic, ginger, greens (all types), kale, mushrooms, onions, parsnips, potatoes (white), radicchio, scallions, shallots, spinach, tomatoes, turnips, watercress

Fruits: Apples (fresh, cider, juice, sauce), apricots, bananas, coconut, cranberries (dried, juice), dried fruit, figs, lemon, lime, oranges, pears, pineapple, raisins

Grains and Grain Products: Barley, corn, couscous, millet, oats, pasta, quinoa, rice

Dairy and Non-Dairy Products: Browned butter, butter, cheese (esp. blue, feta, Fontina, goat, Parmesan), coconut butter, coconut cream, coconut milk, cream, crème fraiche, ghee, milk (dairy and non-dairy), sour cream, yogurt

Other Foods: Agave nectar, bourbon, caramel, chocolate, hoisin sauce, honey, maple syrup, miso, molasses, mustard (Dijon), oil (esp. grapeseed, hazelnut, olive, peanut, sesame, walnut), rum, soy sauce, stock, sugar (esp. brown), tamari, vinegar (esp. balsamic, red wine, rice wine, sherry)

Sweet potatoes have been used in the following cuisines and dishes…
Baked goods (i.e., biscuits, breads, cakes, cookies, muffins, pies), burritos, casseroles, chips (vegetable), croutons, curries, custards, desserts (i.e., custards, pies, puddings), gratins, hash, Indian cuisine, Italian cuisine, Japanese cuisine, pancakes, pasta dishes, pâtés, purees, quesadillas, salads, salsa, shepherd’s pie, soufflés, soups (i.e., black bean, sweet potato, tomato), stews, tempura, waffles (sweet potato)

Suggested Food and Flavor Combos Using Sweet Potatoes
Add sweet potatoes to any of the following combinations…

Allspice + Cinnamon + Ginger + Maple Syrup + Nutmeg [+ vanilla]
Almond milk + Cinnamon + Maple Syrup + Nutmeg [+ vanilla]
Almonds + Almond Milk + Apples
Apples + Ginger
Avocado + Black Beans + Chiles
Balsamic Vinegar + Kale + Sage
Bell Peppers + Garlic + Onions [in hash]
Black Beans + Cilantro + Mango [in salsa]
Black Beans + Salsa [in tortillas]
Browned Butter + Sage
Brown Sugar + Cinnamon + Vanilla
Brown Sugar + Citrus Juice
Brown Sugar + Ginger
Chiles + Ginger + Lime + Salt
Chiles + Honey
Chocolate + Cinnamon + Nuts + Vanilla
Coconut Milk + Curry Spices
Garlic + Herbs (i.e., rosemary, sage, thyme)
Ginger + Honey + Sesame Seeds/Oil + Soy Sauce
Ginger + Lime + Pears
Ginger + Orange + Yogurt
Ginger + Sesame Oil/Seeds
Greens + Quinoa
Honey + Lime
Maple Syrup + Pecans
Molasses + Sesame Seeds
Nuts + Raisins
Sesame Seeds/Oil + Soy Sauce

Recipe Links
Butter Roasted Sweet Potatoes https://www.thekitchn.com/recipe-butter-roasted-sweet-potatoes-248389

Sweet Potato Pancakes https://www.thekitchn.com/recipe-sweet-potato-pancakes-224305

7-Minute “Quick Steamed” Sweet Potatoes http://www.whfoods.com/genpage.php?tname=recipe&dbid=325

Healthy Mashed Sweet Potatoes http://www.whfoods.com/genpage.php?tname=recipe&dbid=94

Sweet Potatoes with Ginger and Cinnamon http://www.whfoods.com/genpage.php?tname=recipe&dbid=205

Maple Mashed Sweet Potatoes with Bacon https://producemadesimple.ca/maple-mashed-sweet-potatoes-bacon/

Sweet Potato Muffins https://producemadesimple.ca/sweet-potato-muffins/

Spicy-Sweet Roasted Sweet Potatoes https://spicysouthernkitchen.com/spicy-sweet-roasted-sweet-potatoes/

Rosemary Roasted Sweet Potatoes https://tasty.co/recipe/rosemary-roasted-sweet-potatoes

50+ Delicious New Ways to Prepare Sweet Potatoes https://www.countryliving.com/food-drinks/g877/sweet-potato-recipes-1009/

Glazed Sweet Potatoes https://www.tasteofhome.com/recipes/glazed-sweet-potatoes/

Roasted Sweet Potatoes with Honey and Cinnamon https://www.foodnetwork.com/recipes/tyler-florence/roasted-sweet-potatoes-with-honey-butter-recipe-1946538

57 Killer Sweet Potato Recipes to Make This Fall https://www.delish.com/holiday-recipes/thanksgiving/g622/sweet-potato-recipes/

Sweet Potatoes with Apple Butter https://www.foodandwine.com/recipes/sweet-potatoes-apple-butter

20 Diners That All Start with Sweet Potatoes https://www.thekitchn.com/15-ways-to-turn-sweet-potatoes-into-dinner-236137

6 Amazing Ways to Stuff a Sweet Potato https://www.onelovelylife.com/6-amazing-ways-to-stuff-a-baked-sweet-potato/

Honey Roasted Chicken and Sweet Potatoes Skillet https://www.lecremedelacrumb.com/honey-roasted-chicken-sweet-potatoes-skillet/

Red Lentil Sweet Potato Soup https://www.thekitchn.com/recipe-red-lentil-sweet-potato-soup-253246#post-recipe-13007

 

Resources
http://www.whfoods.com/genpage.php?tname=foodspice&dbid=64

https://www.everydayhealth.com/diet-nutrition/diet/sweet-potato-nutrition-benefits-recipes-more/

https://www.thekitchn.com/whats-the-difference-between-yams-and-sweet-potatoes-word-of-mouth-211176

https://draxe.com/sweet-potato-nutrition-facts-benefits/

https://www.ncbi.nlm.nih.gov/pubmed/14747225

https://www.runtastic.com/blog/en/7-eating-habits-of-the-worlds-healthiest-populations/

https://nutritionfacts.org/2018/01/11/what-do-the-longest-living-people-eat/

https://curiouschef.com/wordpress/crisp/blog/flavors-pair-well-sweet-potato/

https://www.almanac.com/plant/sweet-potatoes#

https://www.realsimple.com/food-recipes/shopping-storing/food/fresh-pick-sweet-potatoes

https://www.thespruceeats.com/how-to-freeze-sweet-potatoes-three-ways-3061558

https://nutritionfacts.org/2015/11/24/is-it-better-to-bake-boil-or-steam-sweet-potatoes/

https://www.ncbi.nlm.nih.gov/pubmed/12002680

https://www.healthline.com/nutrition/sweet-potato-benefits

https://www.loc.gov/everyday-mysteries/item/what-is-the-difference-between-sweet-potatoes-and-yams/

https://www.thekitchn.com/sweet-potato-recipes-tips-and-ideas-22928259

https://www.diabetesselfmanagement.com/blog/glycemic-index-confusion/

https://lacanadacarecenter.com/15-health-benefits-of-sweet-potatoes-according-to-science/

https://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2667/2

https://www.stilltasty.com/fooditems/index/18450

https://www.unlockfood.ca/en/Articles/Cooking-And-Food/Vegetables-and-Fruit/All-About-Sweet-Potato.aspx

Joachim, David. (2010) The Food Substitutions Bible. 2^nd Edition. Toronto, Ontario, Canada: Robert Rose, Inc.

Page, Karen. (2014) The Vegetarian Flavor Bible. New York, NY: Little, Brown and Company.

 

About Judi

Julia W. Klee (Judi) began her journey enjoying “all things food” in elementary school when she started preparing meals for her family. That love of food blossomed into a quest to learn more and more about health and wellness as related to nutrition. She went on to earn a BS Degree in Food and Nutrition, then an MS Degree in Nutrition. She has taught nutrition and related courses at the college level to pre-nursing and exercise science students. Her hunger to learn didn’t stop upon graduation from college. She continues to research on a regular basis about nutrition as it relates to health. Her hope is to help as many people as possible to enjoy foods that promote health and wellness.