Research published in the Journal of Food Processing and Preservation has demonstrated that darker coloured potatoes retain a higher level of antioxidants after processing than standard ones.
Nayak and colleagues from Washington State University and the Western Regional Research Center, processed white, yellow, red and purple potatoes using standard industry techniques and measured levels of antioxidants, total phenolics and total anthocyanins before and after processing. Purple potatoes had significantly higher levels in all 3 tests and levels remained higher after processing. The authors suggest using purple potatoes to produce healthier snacks than those containing lighter potatoes.