Determination of total anthocyanidins in purple sweet potato by vis spectrophotometry.

Purple sweet potato is rich of anthocyanidins. Its application prospect and economic benefits has aroused more and more concerns. Herein, total anthocyanidins in purple sweet potato were extracted under the ultrasonic irradiation and determined by UV-Vis spectrophotometry using cyanidin as standard combing with the bleaching of Na2SO3. Cyanidin shows good linearity from 0 to 30ug/mL with linear correlation coefficient of 0.99968 and detection limit of 0.5ug/mL. The method is facile and accurate, which should be able to guide the cultivating and planting of purple sweet potato.