Polyphenol extraction from buckwheat and its antioxidant activities

To obtain the optimum parameter of polyphenol extraction from buckwheat, this paper took extracting temperature, time, ethanol concentration and sample-to-solvent ratio as single factor, and the yield of total polyphenol as response value, applied response surface methodology trial to experiment. And the antioxidant activities of the optimized buckwheat extraction were analyzed. Results showed that the orders of each factor influenced the buckwheat polyphenol yield were as follows:sample-to-solvent ratio >ethanol concentration >extract temperature >extract time, and the optimized conditions were temperature 56℃, time 6.0h, sample-to-solvent ratio 1 ∶12g/m L, ethanol concentration 65%. The antioxidant activities of extracts obtained at optimal conditions were as follows:2mg/m L buckwheat extraction had the maximum capacity of scavenging of hydroxide radical at 20 min, the value was 26.88%, and also had the maximum capacity of scavenging of DPPH· at30 min, the value was 43.65%. 3mg/m L buckwheat extracts showed the maximum capacity of reducing power at10 min, the value was 2065.39.