Lab results indicated that on a scale of 100, broccoli had an antioxidant value of almost 96, potatoes had about 69, carrots had 32, onions had 25 and bell peppers had 15. The greatest concentration of antioxidants in the potato was in the skin, Howard noted. Preliminary studies by Miller and Howard point to patatin, the major water-soluble protein in potatoes, as being the possible source of the antioxidant activity. People tend to think of potatoes only as high in starch and carbohydrates. Indeed, many people don't realize that one potato also contains half of the daily recommended amount of vitamin C and 750 milligrams of potassium, an element linked to the possible prevention of such ailments as stroke, he said.
Potatoes also are high in dietary fiber and iron.
Yet even though the excellent nutritional value of potatoes may not be common knowledge, the fleshy tuber already is the fourth most important food crop in the world, only slightly behind rice, wheat and corn. Potatoes are a much-loved food in the United States where annual per capita consumption is 125 pounds. The researchers plan to examine the effect of cooking on antioxidants as well as the influence of the environment on potato plants in the field, the variability of antioxidants among potato varieties, and genetic markers in potato varieties with the highest antioxidant activity. Miller said finding answers to these questions will help breeders develop an even more nutritious and health-promoting potato.