Purple potatoes, also known as blue potatoes, are eye-catching tubers with deep purple skin and flesh. Their vibrant color comes from antioxidant pigments called anthocyanins. Some people wonder if the purple pigment in these potatoes will disappear when cooked.
Do Purple Potatoes Lose Their Color When Cooked?
The short answer is: Yes, purple potatoes can lose some of their bright purple color when cooked. However, they tend to keep more of their color than many other pigmented fruits and vegetables.
When you cook purple potatoes, the high temperatures break down some of the anthocyanin pigments. This causes the purple color to fade or leach out into the cooking water. However, purple potatoes tend to retain much of their antioxidant pigments and nutrients even after cooking.
Why Do Anthocyanins Break Down During Cooking?
Anthocyanins are water-soluble pigments that can degrade under certain conditions:
- Heat: High temperatures from cooking break anthocyanins down.
- Water: Moisture and liquids allow anthocyanins to leach out.
- pH: Anthocyanins change color based on pH. Alkaline environments turn them green.
- Time: Longer cooking times destroy more anthocyanins.
- Light: Light exposure over time fades and degrades anthocyanins.
For this reason, the anthocyanins in purple potatoes will start to break down when boiled, sautéed, roasted, or otherwise cooked in moist heat. This causes them to lose some of their bright purple hues.
Cooking Methods That Preserve More Color
Some cooking methods help purple potatoes retain more of their color than others:
Baking, Roasting, or Grilling
Dry heat methods like baking, roasting, or grilling purple potatoes result in less color loss. With dry heat, the pigments don’t leach out into water. Shorter cook times also preserve more color.
Microwaving or Boiling
Wet cooking methods like microwaving or boiling cause more leaching of anthocyanins. If you boil purple potatoes, keep the water to use for serving to retain more of the colorful phytonutrients.
Steaming
Steaming is a moist cooking method that preserves more color than boiling. The anthocyanins that leach out are captured in the steam rather than being completely lost in the water.
Stir-Frying or Sautéing
Quick stir-frying or sautéing retains more color than prolonged cooking. Use small amounts of oil or broth instead of lots of water to reduce leaching of pigments.
Tips to Preserve Color When Cooking Purple Potatoes
Here are some tips to help keep purple potatoes more vibrant during cooking:
- Leave the skin on. The skin contains the highest concentration of anthocyanins.
- Cut into larger pieces to reduce surface area for less leaching of pigments.
- Start in cold water and bring to a boil for less breakdown of anthocyanins.
- Avoid soaking before cooking. This allows pigments to leach out.
- Use minimal water or oil/broth when cooking to reduce leaching.
- Cook for shorter times to preserve more anthocyanins.
- Acidic ingredients like lemon or vinegar help stabilize the purple pigment.
How Much Color Loss Occurs with Cooking?
Studies have measured how much purple pigment is lost from potatoes during cooking:
Cooking Method | Anthocyanin Loss |
---|---|
Microwaving whole | 14-22% |
Boiling whole | 14-27% |
Steaming whole | 10-15% |
Baking whole | 10-12% |
Frying chips | 10-19% |
Boiling peeled, cubed | 41-59% |
This data shows that purple potatoes retain much of their anthocyanin pigments even when cooked. Leaving the skin on provides the most protection. Peeled, cubed potatoes boiled in lots of water lose the most anthocyanins.
Factors That Affect Color Loss
There are a few factors that influence how much color purple potatoes retain when cooked:
Potato Variety
Some purple potato varieties contain more anthocyanins and retain more color when cooked. Varieties like Purple Majesty and Purple Viking keep more purple hues than others.
Growing Conditions
Growing conditions like sunlight, temperature, soil quality, and water affect anthocyanin levels in purple potatoes. Potatoes with higher initial anthocyanins keep more color when cooked.
Cooking Method
As shown above, cooking method has a significant impact. Dry heat retains more color than wet heat. Boiling causes the most leaching of anthocyanins.
Preparation
Keep skins on and cut into larger pieces to retain more anthocyanins during cooking. Peeling and chopping into small cubes causes more degradation of purple pigments.
Cooking Time
The longer purple potatoes cook, the more anthocyanin degradation occurs. Lightly cooked or parboiled potatoes retain more color than those cooked for long periods.
pH
Acidic ingredients help stabilize anthocyanins. Adding a squeeze of lemon or dash of vinegar to the cooking water can help purple potatoes retain more color.
Do Cooked Purple Potatoes Lose Nutrients?
Along with anthocyanins, purple potatoes contain other beneficial phytonutrients:
- Vitamin C
- Vitamin B6
- Potassium
- Magnesium
- Phosphorus
- Antioxidants like carotenoids
Some water-soluble vitamins like vitamin C and B6 leach out during cooking like the anthocyanin pigments. However, purple potatoes retain much of their nutritional value even after cooking. For example, one study found microwaved purple potatoes retained over 90% of their total polyphenol content.
Nutrient Retention of Cooked Purple Potatoes
Nutrient | Retention After Cooking |
---|---|
Vitamin C | 71-90% |
Total Polyphenols | 83-92% |
Anthocyanins | 59-86% |
Carotenoids | 100% |
Minerals like Potassium | 100% |
This data shows that while some phytonutrients degrade, purple potatoes retain a significant amount of nutrients even after cooking. The complete retention of minerals and carotenoids is notable.
Health Benefits of Cooked Purple Potatoes
Here are some of the key health benefits that remain even in cooked purple potatoes:
Antioxidants
Purple potatoes are packed with antioxidant phytonutrients including anthocyanins and carotenoids. Though some antioxidants degrade during cooking, cooked purple potatoes retain a high antioxidant capacity.
Anti-Inflammatory Effects
The antioxidants in purple potatoes provide anti-inflammatory benefits. Animal studies show cooked purple potato preparations reduce inflammatory markers.
Blood Pressure and Heart Health
The anthocyanins in purple potatoes may support lower blood pressure levels and healthy blood circulation. These effects are still observed in cooked purple potatoes.
Anti-Cancer Properties
Studies suggest the anthocyanins in purple potatoes may help fight cancer cell growth. Cooking does not eliminate these protective effects.
Digestive Health
The resistant starch and fiber in potatoes, including purple varieties, feeds beneficial gut bacteria and promotes good digestive health – even after cooking.
Satiety
Like other types of potatoes, cooked purple potatoes are very filling and can help control appetite and food intake.
How to Use Cooked Purple Potatoes
Here are some serving ideas for cooked purple potatoes:
- Breakfast: Potatoes O’Brien, breakfast tacos or burritos, purple potato hash
- Side dishes: Mashed, roasted, grilled, sautéed, or boiled and tossed with olive oil
- Soups: Add chopped purple potatoes to soups like potato leek
- Salads: Toss in roasted or boiled purple potato chunks
- Entrees: Shepherd’s pie or potato gnocchi with purple potatoes
Cooked purple potatoes work very similarly to regular white potatoes. Their vibrant color adds eye appeal and phytonutrient benefits to any dish.
Should You Peel Purple Potatoes Before Cooking?
It’s best to leave the skins on purple potatoes if possible when cooking. Here’s why:
- The skin contains the highest concentration of anthocyanins.
- Peeling removes potent antioxidants and fiber found in the skin.
- It prevents leaching of nutrients into the cooking water.
- The skin helps maintain the structural integrity when boiling or roasting.
- The skin provides texture and visual appeal in many cooked dishes.
However, peeling may be recommended in certain recipes where the skin could get rubbery or tough. Just keep in mind peeling causes more nutrient loss.
Ways to Cook Purple Potatoes with Skins On
- Boil small or halved potatoes
- Roast chopped or quartered potatoes
- Grill thick potato planks or wedges
- Microwave whole potatoes
- Sauté diced potatoes
- Bake potato halves, stuffed potatoes, or casseroles
Are Purple Potatoes Better for You Than White Potatoes?
Purple potatoes are generally considered healthier than traditional white potatoes. Here’s how they compare:
Purple Potatoes | White Potatoes | |
---|---|---|
Calories | 77 per 100 g | 87 per 100 g |
Carbohydrates | 18 g per 100 g | 20 g per 100 g |
Dietary Fiber | 3 g per 100 g | 2 g per 100 g |
Vitamin C | 30 mg per 100 g | 7 mg per 100 g |
Vitamin B6 | 0.3 mg per 100 g | 0.4 mg per 100 g |
Potassium | 350 mg per 100 g | 425 mg per 100 g |
Phytonutrients | Higher anthocyanins | Lower anthocyanins |
While nutrient content varies among specific purple and white potato types, purple varieties generally contain more vitamin C, fiber, and beneficial plant compounds. Their bright color comes from extra anthocyanin antioxidants.
Healthiest Ways to Cook Purple Potatoes
To maximize the nutrition in purple potatoes, follow these healthy cooking tips:
- Leave the skin on
- Chop into large chunks rather than small cubes
- Lightly steam, bake, or roast instead of boiling
- Use minimal water or broths when sautéing or cooking
- Avoid overcooking – cook just until tender
- Toss with lemon juice or vinegar after cooking
- Enjoy the water used for boiling as a nutritious broth
Some Healthy Recipe Ideas
- Roasted purple potatoes and Brussels sprouts
- Sheet pan chicken sausage with purple potatoes
- Purple potato salad with Greek yogurt dressing
- Purple potato breakfast hash with peppers and onions
- Purple mashed potatoes made with almond milk and garlic
Conclusion
While purple potatoes can lose some of their bright purple pigment when cooked, they retain much of their antioxidant phytonutrients and vitamins. Their color fades less compared to many other anthocyanin-rich foods. Leaving the skin on and using dry heat methods like roasting or baking help minimize anthocyanin loss. Though cooked purple potatoes may become less purple, they maintain a high nutritional profile with many health benefits. Their vibrant color alone makes them a nutritious and eye-catching alternative to regular white potatoes.