| Plants and plant products |
Sweet Potato, more than sweetness
The sweet potato (Ipomoea batatas) is known for its large, sweet-tasting tuberous roots used as a root vegetable. The plant is not closely related to common potatoes and is native to tropical regions of the Americas.
Cultivars with varied flesh and skin colors have been developed. Despite the term "yams" being used for darker sweet potatoes in North America, they are not true yams.
Baked sweet potato contains 76% water, 21% carbohydrates, 2% protein, and negligible fat. One hundred gram baked sweet potato provides 90 calories, 120% of the Daily Value (DV) of vitamin A, vitamin C (24% DV), manganese (24% DV), and vitamin B6 (20% DV). It is a moderate source (10-19% DV) of some B vitamins and potassium.
Phytochemical Riches
• Sweet potatoes boast a plethora of bioactive compounds, including (poly)phenols, carotenoids, terpenoids, tannins, saponins, glycosides, alkaloids, and phytosterols.
• The color variation in sweet potatoes reflects differences in their phytochemical profiles. Purple varieties are rich in anthocyanins, while orange and yellow ones are abundant in (poly)phenols and carotenoids.
• Anthocyanins, particularly in purple sweet potatoes, exhibit strong antioxidant and anti-inflammatory properties.
• Carotenoids, especially β-carotene in orange varieties, contribute to vitamin A intake and offer antioxidant benefits.
Health Advantages
• Antioxidant Activity. The various phytochemicals combat free radicals and oxidative stress, potentially reducing the risk of chronic diseases.
• Hepatoprotective Effects. Anthocyanins from purple sweet potatoes may protect the liver from damage caused by toxins and oxidative stress.
• Cognitive and Memory Improvement. Studies suggest that purple sweet potato compounds may enhance cognitive function and protect against neurodegenerative diseases.
• In Vitro and In-Vivo Cancer Chemoprevention. Extracts and specific phytochemicals from sweet potatoes have shown promising antitumor activity against various cancer cell lines and in animal models.
Cooking Techniques
• Cooking can generally increase the Total Phenolic Content (TPC) in sweet potatoes, with roasting causing the highest rise.
• Steaming, microwaving, baking, and boiling also enhance TPC to varying degrees.
• Water-soluble phenolics are susceptible to leaching during boiling, causing potential loss. Anthocyanins are sensitive to heat and cooking methods affect them differently. Baking may cause the highest loss, while steaming or boiling might increase content in some cases.
• Boiling and frying retain over 90% of the β-carotene content in sweet potatoes.
Key Takeaways
• Minimizing cooking time and temperature, and limiting contact with water, can help preserve beneficial components.
• Choose cooking methods that promote or minimally affect the desired bioactive compounds.
• Pay attention to cooking time and temperature to avoid unnecessary degradation.
• Consider diverse cooking methods to benefit from a wider range of bioactives.
Table 1: Sweet potato nutritional content per 50g.
| Nutrient | Baked in skin | Boiled, without skin |
| Vitamin A (µg RAE) | 0.0 | 393.5 |
| Vitamin C (mg) | 9.8 | 6.4 |
| Vitamin D (µg) | 0.0 | 0.0 |
| Vitamin E (mg) | 0.4 | 0.5 |
| Vitamin K (µg) | 1.2 | 1.1 |
| Thiamin (mg) | 0.1 | 0.0 |
| Riboflavin (mg) | 0.1 | 0.0 |
| Niacin (mg) | 0.7 | 0.3 |
| Vitamin B6 (mg) | 0.1 | 0.1 |
| Folate total (µg) | 3.0 | 3.0 |
| Vitamin B12 (µg) | 0.0 | 0.0 |
| Pantothenic acid (mg) | 0.4 | 0.3 |
| Carbohydrate (g) | 10.4 | 8.9 |
| Fiber total dietary (g) | 1.7 | 1.3 |
| Protein (g) | 1.0 | 0.7 |
| Calcium (mg) | 19.0 | 13.5 |
| Copper (mg) | 0.1 | 0.0 |
| Iron (mg) | 0.3 | 0.4 |
| Magnesium (mg) | 13.5 | 9.0 |
| Manganese (mg) | 0.2 | 0.1 |
| Phosphorus (mg) | 27.0 | 16.0 |
| Selenium (µg) | 0.1 | 0.1 |
| Zinc (mg) | 0.2 | 0.1 |
| Potassium (mg) | 237.5 | 115.0 |
| Sodium (mg) | 123.0 | 131.5 |
| Other nutrients | ||
| Alpha carotene (µg) | 0.0 | 0.0 |
| Ash (g) | 0.7 | 0.3 |
| Beta carotene (µg) | 0.0 | 4722.0 |
| Beta cryptoxanthin (µg) | 0.0 | 0.0 |
| Cholesterol (mg) | 0.0 | 0.0 |
| Choline total (mg) | 6.6 | 5.4 |
| Energy (Kcal) | 46.0 | 38.0 |
| Fatty acids mono (g) | 0.0 | 0.0 |
| Fatty acids poly (g) | 0.0 | 0.0 |
| Fatty acids sat (g) | 0.0 | 0.0 |
| Folate DFE (µg) | 3.0 | 3.0 |
| Folic acid (µg) | 0.0 | 0.0 |
| Food folate (µg) | 3.0 | 3.0 |
| Lipid total (g) | 0.1 | 0.1 |
| Lutein+zeazanthin (µg) | 0.0 | 0.0 |
| Lycopene (µg) | 0.0 | 0.0 |
| Retinol (µg) | 0.0 | 0.0 |
| Sugar total (g) | 3.2 | 2.9 |
| Vitamin A (IU) | 0.0 | 7870.0 |
| Vitamin D (IU) | 0.0 | 0.0 |
| Water (g) | 37.9 | 40.1 |
Sources
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9495970/
• https://en.wikipedia.org/wiki/Sweet_potato
• USDA Nutritional Database
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