Darker-roasted peanuts pack a greater antioxidant punch, according to Agricultural Research Service (ARS) scientists in North Carolina. The researchers measured antioxidant levels in peanuts roasted at 362 degrees from zero to 77 minutes. Longer, darker roasting was consistently associated with higher levels of both water- and oil-soluble antioxidants, which scientists attributed to greater concentrations of phenolic compounds and/or browning reaction products. The latter result from thousands of complex chemical reactions in which proteins and sugars interact; these reactions, collectively termed Maillard browning, are also thought to contribute to the characteristic flavor of roasted peanuts. Researchers also measured vitamin E, finding that oil from darker-roasted peanuts retained vitamin E even better than in raw peanuts.