Study on Extraction of Total Flavonoids from Grape Skin and Its Antioxidation Effects

[Objective] To optimize the extraction process of flavonoids from grape skin and its effect to scavenge the hydroxyl free radicals.[Method] With the grapes sold on market as materials,the main factors influencing the extraction rate of total flavonoids were analyzed by orthogonal experiment,the effects of four factors,including ethanol concentration,reflux temperature,reflux time and solid-liquid ratio,on the extraction rate of flavonoids were studied,and the best extraction conditions were found out.[Result] The best extraction conditions were 40% of ethanol concentration,1 h of extraction time,1∶15(g/ml) of solid-liquid ratio and 85 ℃ of extraction temperature,under which the total amount of extracted flavonoids was 65.17 mg/g.The grape skin contained some effective components with the scavenging capacity of hydroxyl free radicals.[Conclusion] The best extraction conditions of total flavonoids were obtained in this study,providing scientific basis for the medical value of grape skin.