Raw sweet potatoes, like raw lima beans, contain cyanogenic glycosides, natural
chemicals that break down into hydrogen cyanide in your stomach or when the potato is
heated. If you pierce the potato while it is baking or leave the lid off the pot while it is boil-
ing, the hydrogen cyanide (a gas) will float off harmlessly into the air.
The Most Nutritious Way to Serve This Food
Baked or boiled.
Diets That May Restrict or Exclude This Food
Buying This Food
Look for: Solid, well-shaped sweet potatoes, thick in the center and tapering toward the
ends. The potatoes should feel heavy for their size and the skin should be evenly colored
and free of blemishes, bruises, and mold. Moldy sweet potatoes may be contaminated with
a number of toxins including the liver toxin ipomeamarone and a toxic derivative, ipomea-
maronol. These toxins cannot be destroyed by normal boiling or baking.
Storing This Food
Handle sweet potatoes gently to avoid bruising. When you bruise a sweet potato you tear
some of its cells, releasing polyphenoloxidase, an enzyme that hastens the oxidation of phe-
nols in the potato, creating brown compounds that darken the potato.
Store sweet potatoes in a cool (55–60°F), dark cabinet, not in the refrigerator. Like
bruising, very cold temperature damage the potato’s cells, releasing polyphenoloxidase and
darkening the potato.
Store home-grown sweet potatoes at 85°F for four to six days right after harvesting to
sweeten them by increasing the natural conversion of starches to sugars.
Preparing This Food
Scrub sweet potatoes under cool running water. Boiling the potatoes in their skin will save
more vitamins since you will be able to peel them more closely after they are cooked. If you
plan to bake the sweet potatoes, pierce the skin with a cake tester to let the steam escape as the
potato cooks, and insert an aluminum “potato nail” to carry heat evenly through as it bakes.
Sweet Potatoes