Optimizing the extraction and the antioxidant activity of anthocyanins from purple sweet potato by using response surface methodology

The response surface methodology was used to optimize the hot water extraction of anthocyanins from purple sweet potato. Three parameters including citric acid mass fraction, extraction temperature and extraction time were optimized based on anthocyanins content and the antioxidant activity of the extract. The optimum extraction conditions were citric acid mass fraction 3%, extraction temperature 63℃ and extraction time 2h for anthocyanins. Under this extraction condition, the extraction rate of purple sweet potato anthocyanins was 7.21mg/g, and the IC50 value for DPPH radical scavenging activity was 123.93μg/m L. The results suggested that the regression models were accurate and adequate for anthocyanins extraction from purple sweet potato, while the extraction showed the highest antioxidant activity.