Sweet potatoes are a delicious and nutritious vegetable that are enjoyed around the world. When cutting open and preparing a sweet potato, you may notice little white specks or strings inside the orange flesh. So what exactly are those white bits? Are they harmful at all? Let’s take a closer look.
The white specks are bundles of sweet potato fibers
The small white specks or strings found throughout the interior of a sweet potato are actually bundles of fibers. Sweet potatoes contain a significant amount of dietary fiber, which gives them many of their health benefits. The little white specks are concentrated bits of this beneficial fiber.
Sweet potato fiber is made up of cellulose, lignin, and pectin. Cellulose and lignin provide structure to plants and make up the cell walls. Pectin is a water-soluble fiber that gives plants flexibility and acts as a bonding agent for cellulose and lignin. When you see the white specks, you are seeing clumps of these important dietary fibers.
Why the fiber bundles appear white
The reason the fiber bundles appear white is due to their light color and also because of their resistance to pigment absorption. The orange hue of sweet potatoes comes from carotenoid pigments, primarily beta-carotene. As the sweet potato root develops, these pigments are absorbed throughout the flesh, giving it the characteristic orange color.
However, the concentrated fiber bundles do not absorb much of the carotenoid pigments, so they remain white in the midst of the orange flesh. They are like little white islands in the orange sea of the sweet potato’s interior.
Are the white specks unhealthy or harmful?
The white specks in sweet potatoes are completely normal and safe to eat. Since they are simply composed of dietary fiber, they do not present any health risks or dangers.
Fiber is highly beneficial for the body and has been linked to improved digestive health, balanced blood sugar levels, reduced cholesterol, and healthier weight maintenance. The white specks are a sign that your sweet potato contains plenty of fiber.
Some people carefully remove the white bits before cooking or eating sweet potatoes, but there is no need to do this. Leaving the fiber bundles intact will provide you with extra nutrition and health benefits.
Preparing and cooking sweet potatoes with white specks
Sweet potatoes with white specks throughout can be used just like any other sweet potato. Here are some tips for preparing and cooking them:
- Wash thoroughly and scrub the skin to remove any dirt.
- Cut off any bruised or damaged sections.
- Leave the skin on or peel according to your recipe or preferences.
- Chop into cubes, slices, wedges, or the shape desired.
- Roast, bake, steam, microwave, or boil until tender when pierced with a fork.
- Mash, puree, or blend to make smooth sweet potato dishes.
The white fiber bundles typically soften during cooking and become less noticeable in mashed or pureed dishes. But they will still provide valuable nutrition to complement the natural sugars and carotenoids of the sweet potato flesh.
Nutrition provided by sweet potatoes and their white fibers
Here is an overview of the nutrition you get in one medium, baked sweet potato (114 grams) with its skin:
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 103 | 5% |
| Fat | 0.1g | 0% |
| Sodium | 41.5mg | 2% |
| Potassium | 337mg | 7% |
| Carbs | 23.7g | 8% |
| Fiber | 3.6g | 14% |
| Sugar | 5.4g | |
| Protein | 2.3g | 5% |
| Vitamin A | 17710IU | 354% |
| Vitamin C | 19.6mg | 32% |
| Calcium | 41mg | 4% |
| Iron | 0.7mg | 4% |
This nutrient profile shows why sweet potatoes are valued as a nutritious vegetable. One of the key benefits is fiber content – a medium sweet potato provides 14% of your daily fiber needs. Those small white specks account for a portion of that valuable dietary fiber.
The white fiber bundles provide insoluble fiber, which is important for healthy digestion and bowel function. They also contain soluble fiber like pectin, which helps control blood sugar and cholesterol.
Additionally, the fiber works synergistically with the antioxidants and vitamins in sweet potatoes, slowing the absorption of the sugars so they provide a steady stream of energy rather than a quick sugar spike and crash.
Other nutrients and benefits
Beyond fiber, sweet potatoes offer many other important nutrients and health benefits:
- Vitamin A – Sweet potatoes are one of the best sources of beta-carotene, which converts to active vitamin A. This vision-protecting vitamin also acts as an antioxidant.
- Vitamin C – Important for immunity and skin health, the vitamin C in sweet potatoes also helps your body absorb the beta-carotene.
- Potassium – Crucial electrolyte helps regulate fluid balance, nerve transmission, and blood pressure.
- Antioxidants – In addition to beta-carotene, compounds like chlorogenic acid and anthocyanins have antioxidant and anti-inflammatory effects.
- Manage blood sugar – The fiber, vitamins, and minerals in sweet potatoes help moderate blood sugar spikes.
- Improve digestion – The high fiber content aids digestion and improves gut health via prebiotic action in the intestines.
How the white fibers affect taste and texture
You may notice that sweet potatoes with more white fiber bundles have a slightly less creamy, soft texture when cooked. The concentrated fiber bits tend to maintain some firmness, while the surrounding flesh softens when roasted or boiled.
This can give the interior a more fibrous, stringy consistency in parts. The overall effect is relatively minor, but you may get a little more texture compared to sweet potatoes with less defined white specks.
In terms of flavor, the taste is not significantly affected. The bundles themselves are fairly mild in flavor. So you’ll still get the characteristic sweetness from the flesh along with the slightly earthy, nutty flavors. The white specks simply add a subtle graininess or strings in the mouthfeel.
Prevalence of white specks in different sweet potato varieties
While all sweet potatoes contain some fiber bundles, certain varieties and individual sweet potatoes exhibit more noticeable white specks than others. Here is a look at some of the differences:
Jewel sweet potatoes
Jewel sweet potatoes have fairly minimal white specks. Their flesh tends to be more uniformly orange compared to other varieties. The coherent strands of pectin and cellulose are less aggregated into visible bundles.
Japanese sweet potatoes
Japanese sweet potatoes like the purple-fleshed Okinawan have slightly more white speckling than Jewels. The white bits tend to be small pinpoints rather than large bundles or strands.
Garnet sweet potatoes
Garnets or red sweet potatoes contain moderately more white specks compared to less fibrous varieties. Their flesh has both white speckles as well as some diffuse thread-like pectin sections.
Hannah sweet potatoes
Hannah sweet potatoes tend to have plentiful white specks and strings dispersed throughout their yellow to orange-hued flesh. The fiber bundles are quite noticeable and contribute to a more fibrous, drier texture when cooked.
| Sweet Potato Variety | Prevalence of White Specks |
|---|---|
| Jewel | Minimal |
| Japanese (Okinawan) | Slight |
| Garnet | Moderate |
| Hannah | Abundant |
Keep in mind even within the same variety, the amount of noticeable white bits can vary between different sweet potatoes based on growing conditions like soil nutrition and climate.
Should you avoid sweet potatoes with more white specks?
Sweet potatoes with minimal white bits often have a softer, creamier cooked texture due to less fiber content. However, the speckled, fiber-rich varieties still make nutritious additions to any diet.
The extra fiber helps regulate digestion and blood sugar levels. The additional vitamin, mineral, and antioxidant intake is also beneficial. So don’t feel you have to avoid those speckled sweet potatoes!
If the increased fiber makes them too stringy or dry for your preferences, try using them in baked goods like muffins, cakes, and quick breads rather than boiled, mashed, or pureed dishes. Baking helps soften the texture while still providing a big nutritional boost.
Are white spots in raw sweet potatoes different from cooked white specks?
When buying fresh, raw sweet potatoes at the store, you may sometimes notice irregular white spots on the surface of the skin. These surface blemishes are unrelated to the interior white fiber specks that appear when cooked.
The white spots on raw sweet potatoes are due to calcification. This is a harmless natural process where areas of the outer skin form hardened white mineral deposits due to changes in the potato’s cell structure.
These white calcified spots do not affect the inner flesh or quality of the sweet potato. Simply peel and remove any damaged outer skin before cooking as usual. The interior should reveal the familiar orange color and scattered white fiber bundles.
What if my sweet potatoes have black, brown, or gray spots?
While small white spots on raw sweet potatoes are normal, other discolored spots may be more concerning. Dark brown, gray, or black spots can indicate underlying damage, bruising, or spoilage.
Blackened areas inside a sweet potato are often due to bruising or impact damage during harvesting, storage, or transport. The inner flesh reacts by creating pigmented compounds that lead to dark discoloration.
Grayish or brown sunken spots may be an early sign of fungal mold or rot developing in areas with skin damage. This can quickly spread to make the sweet potato unfit to eat.
If the dark spots are minor and localized, you can cut away the damaged flesh and cook the remainder of the sweet potato. But any extensive darkening or mold growth means the potato should be discarded.
Can you eat the sweet potato skin?
Unlike regular white potatoes where the skin is often peeled away, sweet potato skins are edible and nutritious. The skin contains heightened amounts of fiber compared to the flesh. It also provides compounds called phytochemicals that may have antioxidant and other health benefits.
Some reasons you may want to eat the sweet potato skin:
- Adds extra fiber, vitamins, and minerals
- Contains beneficial phytochemicals
- Saves time by not peeling
- Adds texture and visual appeal
- Skin becomes tender when roasted or boiled
However, be sure to wash and scrub the skin well before cooking to remove any dirt or bacteria. Peel any bruised spots or discoloration. The skin can be left on for boiling, roasting, baking, and microwaving recipes.
Should you eat the skin of raw sweet potatoes?
It is not recommended to eat the skin of raw sweet potatoes. The skin of raw potatoes may contain compounds like solanine that can cause digestive upset. Cooking helps neutralize these.
Additionally, the raw skin is quite chewy and fibrous. Thorough cooking softens the texture, making the skin palatable to eat when roasted or boiled.
What parts of sweet potatoes can you eat?
Most all parts of the sweet potato are edible after cooking and completely safe to eat.
You can eat:
- The skin – Fiber-rich with antioxidants.
- The white fibers – Provide added nutrition.
- The orange/yellow flesh – Contains beta-carotene and vitamins.
- The leaves – Edible when cooked like spinach.
- The shoots – Somewhat woody but edible when steamed.
- The roots – Fibrous but provide carbohydrates.
Avoid eating any bruised or discolored parts raw. Cook all parts thoroughly before eating. The skin and flesh are most commonly eaten, while the leaves, shoots, and roots are less frequently consumed.
Conclusion
The small white specks and strands found in sweet potatoes are harmless bundles of dietary fiber. They provide extra nutrition without any risks. While less common in some varieties, the speckles are completely normal for this root vegetable.
The fiber bits may add some light textural changes but do not negatively impact flavor. Sweet potatoes with abundant white speckling can be enjoyed just as readily as those with minimal specks. Any variety of thishealthy tuber makes a nutritious addition to your diet.