Abstract: Purple-fleshed potato, rich in phenolic compounds such as anthocyanin, chlorogenic acid, is a good source of natural antioxidants due to its extensive availability and cheapness. This research was performed to investigate the impacts of domestic cooking methods on the contents of anthocyanins, free polyphenols, bound polyphenols and chlorogenic acid and antioxidant activity in purple-fleshed potato for the purpose of achieving maximum retention of the antioxidant bioactives. Three purple-fleshed potato breeding lines and the white potato cultivar ‘Shepody’ were tested in this study. The results showed that all cooking methods significantly reduced anthocyanin contents in purple-fleshed potato varieties; compared with ‘Shepody’, free polyphenols, bound polyphenols and chlorogenic acid contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity in purple-fleshed potatoes increased after steam and microwave treatments, whereas all components except for bound polyphenols decreased after boiling treatment. In conclusion, phenolics could be retained maximally after microwave irradiation and steaming and thus exert their antioxidant activities.

Key words: purple-fleshed potato, cooking treatment, phenolics, antioxidant activity