Potato peel waste: stability and antioxidant activity of a freeze-dried extract

Aqueous extracts of potato peel waste were freeze-dried. High performance liquid chromatography (HPLC) of the freeze-dried extracts revealed that chlorogenic (50.31%), gallic (41.67%), protocatechuic (7.81%), and caffeic (0.21%) acids were the major phenolics. During 15 days storage of the freeze-dried extract, no degradation of phenolics occurred. After 4 days storage at 63 degrees C, 5.00 g of sunflower oil containing either the freeze-dried extract (200 ppm) or butylated hydroxyanisole (BHA) (200 ppm) reached peroxide values (PV) of 37.38 and 37.47 meq kg-1 respectively. L-ascorbic acid-6-palmitate was the best antioxidant (PV = 10.65 meq kg-1) but the freeze-dried extract was as good as BHA