Single factor and orthogonal array design experiments were used to optimize the ultrasonic extraction conditions of polyphenol from sweet corncobs.The total polyphenol content was determined by the Folin-Ciocalteu assay.Results showed that the optimum extraction conditions were as follows: 45 min ultrasonic treatment at 200W power for extracting the raw material with a 15-fold volume of 80% aqueous ethanol solution at 40 ℃.The yield of polyphenol was(2.61±0.09)%,under the optimum condition,and DPPH radical ...