Sweet potatoes, scientifically known as Ipomoea batatas, are a widely consumed root vegetable belonging to the morning glory family, Convolvulaceae. These starchy, sweet-tasting roots are a staple food in many parts of the world. Sweet potatoes commonly sprout when stored.
Why Sweet Potatoes Sprout
Sprouting is a natural biological process for sweet potatoes, indicating that the root is still alive and attempting to initiate new plant growth. This process is essentially the breaking of dormancy, a period during which the plant’s metabolic activity slows down. Warmth and humidity are primary cues that signal to the sweet potato that conditions are favorable for growth. When sweet potatoes are exposed to temperatures above 60°F (16°C), their metabolism accelerates, encouraging the development of sprouts.
Sweet Potatoes Versus Regular Potatoes
A significant distinction exists between sweet potatoes and regular potatoes, Solanum tuberosum, particularly concerning their sprouts. Regular potatoes are members of the nightshade family, Solanaceae, and their sprouts, green skin, and “eyes” contain glycoalkaloids, primarily solanine and chaconine. These compounds are naturally occurring toxins that can cause gastrointestinal upset, headaches, or other adverse effects if consumed in high concentrations.
Sweet potatoes, however, are from a different plant family, the morning glory family. Their sprouts do not produce solanine or similar harmful toxins. This botanical difference means safety concerns associated with sprouted regular potatoes do not apply to sprouted sweet potatoes. While a sprouted sweet potato might experience changes in texture or flavor as its nutrients are redirected to the new growth, the sprouts themselves are not inherently poisonous.
When a Sprouted Sweet Potato Is Still Edible
A sweet potato with small sprouts is generally safe for consumption. The key indicators for edibility are the overall condition of the root. If the sweet potato remains firm to the touch, shows no signs of mold, and does not emit an unpleasant odor, it is likely still suitable for eating. In such cases, the sprouts can be removed before the sweet potato is prepared and cooked.
When a sprouted sweet potato is no longer edible, it typically indicates general spoilage rather than sprout-related toxicity. Discard the sweet potato if it feels soft, mushy, or shriveled, as these are signs of deterioration. The presence of mold, significant discoloration, or a strong, sour, or musty smell indicates spoilage, and it should not be eaten.
Optimal Storage to Prevent Sprouting
Proper storage can significantly delay sprouting and extend the freshness of sweet potatoes. The ideal conditions involve a cool, dark, and well-ventilated environment. Temperatures between 55°F to 60°F (12°C to 16°C) are considered optimal for long-term storage, allowing sweet potatoes to remain fresh for several months. Storing them in a pantry, basement, or a cool cupboard away from direct sunlight is suitable.
Avoid refrigerating sweet potatoes, as temperatures below 50°F (10°C) can cause chilling injury, leading to a condition known as “hard core” where the texture becomes hard even after cooking. Additionally, sweet potatoes should not be stored near fruits that produce ethylene gas, such as apples, as ethylene can accelerate sprouting and deterioration. Ensuring good air circulation by storing them in a breathable container, like a basket or mesh bag, also helps prevent moisture buildup and spoilage.