Abstract: In order to obtain the optimal extraction conditions of polyphenols from the fagaceae plants Castanea mollissima by quadratic rotation orthogonal method,the chestnut shell was used as raw material,and the process of traditional water solution extraction and heating extraction were adopted.The results of single factor experiment were used to design the quadratic rotation orthogonal experiment with the extraction rate of total polyphenols as the assessing factor.The extracts were also tested for its antioxidant activity,and its structural feature was analyzed by spectral methods.The results showed that the optimal conditions for extraction of polyphenols from chestnut shell were:ethanol concentration 57%,extraction temperature 85 ℃ and extraction time 45 min.Under these conditions,the optimal extraction rate of polyphenols from chestnut shell was 5.44%.When the concentration of polyphenols was 1 mg/mL,the hydroxyl radical scavenging rate of the extracts was 8.15%.In addition,the FTIR and UV spectra of the extracts were all consistent with the spectral characteristics of polyphenols.

Key words: shell, polyphenols, antioxidant, quadratic rotation orthogonal