The natural brown pigment of chestnut shells was extracted from chestnut shells produced in Xiuyan area by ultrasound-method. The orthogonal test was used to optimize the extraction conditions. The light stabili-ty, heat stability, pH stability and metal ions stability were studied. The antioxidant activities in vitro of brown pigment was investigated by phenanthroline -Fe2+and pyrogallol autoxidation method. Orthogonal test results showed that the optimal conditions of extraction of the brown pigment of chestnut shells by ultrasonic extraction method was at 75℃, 45%ethanol concentration, 15 min, solid liquid ratio 1∶20 (g/mL). The yield was 7.05%. The brown pigment of chestnuts shells was good at light, heat and pH resistance. It was stable against Na+,K+, Ca2+,Zn2+,Mg2+,Ba2+while was sensitive to Fe3+,Pb2+,Cu2+. In the setting concentration range, the antioxidant activities of brown pigment of chestnut shells increased with the elevation of concentration and were lower than that of VC. The clearance rates of hydroxyl free radical and superoxide anion of 2.0 mg/mL brown pigment of chestnut shells were 55.9%and 65.2%.%以辽宁省岫岩县产的板栗壳为原料，应用超声波萃取法对板栗壳棕色素进行提取。利用正交试验研究棕色素的最佳提取条件，且对棕色素的光稳定性、热稳定性、pH稳定性、对金属离子的稳定性进行了研究，并用邻二氮菲-Fe2+氧化法和邻苯三酚自氧化法考察板栗壳棕色素的抗氧化性。试验结果表明，超声波萃取板栗壳棕色素的最佳条件为温度75℃，料液比1∶20（g/mL），乙醇浓度45%，萃取时间15 min，此时得率为7.05%。板栗壳棕色素具有较好的光稳定性、热稳定性和pH稳定性。Na+，K+，Ca2+，Zn2+，Mg2+，Ba2+对板栗壳棕色素的颜色无明显影响，但Fe3+，Pb2+，Cu2+会与板栗壳棕色素发生反应，生成沉淀并使色素褪色。在实验设置的0.25 mg/mL~2.0 mg/mL浓度范围内，板栗壳棕色素的抗氧化能力随着浓度的增加而增加，且抗氧化能力略低于VC。2.0 mg/mL的板栗壳棕色素对羟自由基和超氧阴离子自由基清除率分别为55.9%和65.2%。
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