Sweet Potatoes (Ipomoea batatas)
I YAM WHAT I YAM
Did you know … at the beginning of the twentieth century in the United States, orange-fleshed sweet potatoes were given the name “yam” to set them apart from the white-fleshed sweet potato that was popular at that time?
What’s the Story?
Maybe it’s best to start off with what sweet potatoes are not. First of all, they’re not even potatoes! All potatoes belong to the Solanaceae family and sweet potatoes belong to the Convolvulaceae family—which is a group of plants that have trumpet-shaped flowers. They’re not yams either. The word “yam” comes from the African word nyami which describes huge root vegetables found in Africa (Dioscoreae family) that are starchier with a slick texture and a stronger, much less sweet taste than the garden variety sweet potato. To help avoid confusion that consumers might have, the United States Department of Agriculture requires “yams” to also have the term “sweet potato” on the label. There are about 400 different varieties, with skins varying in colour from purple to red to orange to yellow to even white. And inside, the “flesh” may be white, orange, or yellow with textures ranging from firm, dry and mealy to soft and moist.
A Serving of Food Lore …
Sweet potatoes, thought to be native to Central America, may be the oldest vegetable known to humans. Remnants have been found in Peruvian caves that date back 10,000 years. Sweet potatoes were first brought to Europe by Christopher Columbus after his first voyage to the New World. Portuguese explorers brought them to Africa, India, Indonesia and southern Asia. Spanish explorers brought them to the Philippines by the sixteenth century and they were also being cultivated in the southern United States at about this same time.
Where Are Sweet Potatoes Grown?
Uganda, India, Vietnam, Japan, China and Indonesia are the main producers of sweet potatoes. In 2004, world production was 127,000,000 tons according to the Food and Drug Organization, with the majority coming from China.
Why Should I Eat Sweet Potatoes?
They are an excellent source of vitamin A and beta-carotene, and a good source of vitamin C, B6, manganese, potassium and fibre. The red variety of sweet potato is an excellent source of the phytochemical lycopene—which may help fight heart disease and breast and prostate cancer. Purple-flesh types are high in anthocyanins, potent antioxidants which protect the body against degenerative diseases.
Throw Me a Lifesaver!
LONGEVITY: A major source of nutrition for the Okinawans is the Okinawan sweet potato, a white-skinned, purple-fleshed version which may be a contributing factor to their long life expectancies.
DIABETES: Rats who ate white-fleshed sweet potatoes had marked improvement in pancreatic cell function, lipid levels, glucose management, and reduced insulin resistance within eight weeks. A human study also showed improved insulin resistance when sweet potatoes were included in the diet.
MEMORY ENHANCEMENT: Rats who ate purple-fleshed sweet potatoes showed significant improvement in cognitive function, which may be attributed to the anthocyanins present in the potato.
CANCER: A cell study showed that sweet potatoes have unique cancer-fighting properties.
BREAST CANCER: A case-control study found that those women who consumed more beta-carotene–rich foods had lower rates of breast cancer. Sweet potatoes are an excellent source of beta-carotene.
COLORECTAL CANCER: A study using male rats found that the development of colon lesions were inhibited when purple sweet potatoes were added to their diet.
GALLBLADDER CANCER: A case-control study involving diagnosed cases of gallbladder cancer found that sweet potatoes were among the vegetables that offered the greatest protective benefit.
KIDNEY CANCER: A Japanese cohort study that followed 47,997 males and 66,520 females for about ten years found that consumption of sweet potatoes was linked to a decreased risk of kidney cancer.
Tips on Using Sweet Potatoes
SELECTION AND STORAGE:
• Choose firm sweet potatoes free of bruises, soft spots and cracks.
• If selecting for carotene content, choose darker varieties.
• Sweet potatoes will stay fresh for about ten days if placed in a dark, cool and ventilated location.
• Do not put uncooked sweet potatoes in the refrigerator.
PREPARATION AND SERVING SUGGESTIONS:
• To prevent them from darkening due to contact with the air, cook them promptly after cutting or peeling them, or place them in a bowl and cover them with water until it is time to cook them.
• Poke holes in them before baking in the oven or in the microwave.
• Kids’ favourites include sweet potato pie and pudding.
• Spread mashed sweet potatoes on a piece of whole-wheat bread, top with a layer of peanut butter and sliced apples.
• Baked sweet potatoes are delicious even when served cold and therefore make a great food to pack in to-go lunches.
by Dawn Jackson Blatner
Servings: 12 • Prep and cooking time: 30 minutes
Dawn’s chips are so simple to make and are a healthier alternative to regular potato chips. You can jazz them up with additional ingredients like chopped garlic and onion and replace regular salt with flavoured salt. Use the fresh-squeezed lime juice. … It really makes a difference. This recipe contains two powerhouse foods.
INGREDIENTS:
3 large sweet potatoes
3 limes, zest and juice
1 teaspoon salt (regular or flavoured)
Cooking spray or oil
DIRECTIONS:
Preheat oven to 350°F/180°C. Slice potatoes into thin crisps (use mandolin for thin and uniform crisps). Lightly grease or spray baking trays with oil. Place a single layer of potatoes on baking trays. Brush tops of potatoes with cooking spray or oil and top with salt and lime zest. Bake until browned, turning once (about 20 to 30 minutes). Sprinkle browned sweet potato chips with lime juice. Serve and enjoy!
BREAK IT DOWN …
Calories: 57; Total fat: 1g; Saturated fat: 0g; Cholesterol: 0mg; Sodium: 210mg; Total carbs: 12g; Fibre: 2g; Sugar: 4g; Protein: 1g.