Optimization of Extraction Process for"Luozishu 4"Anthocyanins by Response Surface Methodology and Their Antioxidant Activity
Using"Luozishu 4"as experimental material,the extraction process of purple sweet potato antho-cyanin was optimized by response surface methodology on the basis of single factor experiment,and the antioxi-dant activity of purple sweet potato anthocyanin was studied.The results showed that the order of the influence of three single factors on the yield of anthocyanin was C(HCl volume fraction)>B(material-liquid)>A(extraction time).The optimal extraction parameters of purple sweet potato anthocyanin were HCl volume fraction 0.75%,material-liquid ratio 1∶20(g/mL),and extraction time 20 min.Under the optimal extraction conditions,the aver-age yield of anthocyanin reached 108.55 mg/100 g,with RSD of 0.05%,and the relative error with the theoretical value(108.84 mg/100 g)was 0.27%.The antioxidant activity test showed that purple sweet potato anthocyanin had good scavenging ability to DPPH and good reducing ability.When the concentrations of purple sweet potato anthocyanin and vitamin C were the same,their antioxidant change trend were the same,and the antioxidant a-bility of purple sweet potato anthocyanin was stronger than that of vitamin C.