Optimization of Extraction of Polyphenols and Total Flavonoids from Dried Figs by Response Surface Methodology and Antioxidant Activity Analysis

Response surface analysis method was applied to optimize the extraction process of dried figs,and evaluate the antioxidant activities. On the basis of single-factor test,the extraction conditions(ethanol concentration,extraction temperature,extraction time and material/liquid ratio)were analyzed and optimized by the Box-Behnken design,and researched the antioxidant activity of dried figs extract. Results showed that,the optimal extraction parameters were found as follows:Ethanol concentration 60%,extraction temperature 51 ℃,extraction time 52 min,material/liquid ratio 1:45 (g/mL). The yield of polyphenols was(2.72±0.37) mg/g,and the yield of total flavonoids was(20.89±0.57) mg/g under these conditions. The antioxidant activities were evaluated and compared with V_C. The results showed that,the antioxidant activity of total reducing power,hydroxyl(highest:95.54%)and DPPH free radical scavenging(highest:66.73%)abilities of polyphenols was higher than V_C,but the super-oxide anion free radical scavenging(highest:35.15%)abilities was lower than V_C,while the antioxidant activity of total flavonoids was lower than V_C. The present study also found that after treatment with artificial gastric fluid,the total reducing power and hydroxyl free radical scavenging abilities was significantly increased but the DPPH and the super-oxide anion free redical scavenging abilities was significantly decreased. After treatment with artificial intestinal fluid,the total reducing power and the super-oxide anion free redical scavenging abilities was significantly increased but the DPPH and hydroxyl free radical scavenging abilities was significantly decreased.