Abstract: Acidified ethanol method was applied to extract anthocyanins from red raspberry (Rubus idaeus), and the optimal extraction conditions were determined by orthogonal array design. Treatment at 60 ℃ for 1.5 h using 20-fold volume of 80% ethanol aqueous solution containing hydrochloric acid (pH 3) as extraction solvent provided optimum extraction of anthocyanins, and an anthocyanin yield of 0.625 mg/g was achieved. In addition, the resulting extract was evaluated for its antioxidant activity. It was found that the extract displayed dose-dependent reducing power and abilities to scavenge hydroxyl and superoxide anion free radicals in the concentration range investigated here, and that the half-maximal effective concentrations (EC50) against hydroxyl and superoxide anion free radicals were 0.175 mg/mL and 0.699 mg/mL, respectively, indicating that the extract has stronger ability to scavenge hydroxyl free radicals than to scavenge superoxide anion free radicals.

Key words: red raspberry, anthocyanins, extraction, antioxidation