Optimization of Extraction Process of Taxifolin from Grape Pomace and Determination of Its Antioxidant Capacity

The ethanol heating method was used to extract grape pomace,and response surface methodology was used to optimize the extraction process. Then the antioxidant activity was determined in the optimal group.The results showed that the optimum extraction conditions were as follows:standing time 30 min,ethanol content 58%,extraction temperature 56 ℃,liquid-solid ratio 23:1 mL/g,extraction time 2.0 h,and the optimum extraction amount was 3.936 mg/g.Taking V_C as reference,the scavenging ability of grape taxifolin extract to ABTS free radical,DPPH free radical and iron ion reducing power was higher than that of V_C solution,and the scavenging effect on DPPH free radical was the best.The scavenging rate of 50 μg/mL extract on DPPH free radical could reach 90%.In addition,the IC₅₀ values of the extracts of taxifolin to ABTS and DPPH free radical were 28.15 and 22.65 μg/mL,respectively.The results are significant for the development and utilization of grape pomace.