The little changes in antioxidant activity after frying was observed in Valfi, while in Blaue St. Galler and Vitelotte varieties significant reduction (around 75% and 50% respectively) in radical scavening activity was detected. Similar effect – considerable reduction in antioxidant activity after frying of red and purple fleshed potatoes, was observed in other studies by Brown, Durst, Wrolstad, and Jong (2008).