采用不同极性有机溶剂对脱脂米糠乙醇粗提取物进行液-液萃取,将粗提物划分为3个不同极性组分(乙酸乙酯萃取物、正丁醇萃取物、水相残留物);选用总还原力、DPPH自由基清除率、超氧阴离子清除率及金属螯合能力对粗提物和萃取物进行抗氧化活性评价。结果表明:脱脂米糠醇提物具有较好的抗氧化活性。正丁醇萃取物的总还原力(浓度为2.5mg/mL时,吸光值达0.862)、DPPH自由基清除能力(浓度为3mg/mL时,清除能力达61.98%)、超氧阴离子清除能力(浓度为10mg/mL时,清除能力达52.39%)和金属螯合能力(浓度为5mg/mL时,螯合能力达83.77%)较佳,且总多酚类物质、总黄酮含量也显著高于其他组分;正丁醇萃取物呈现出最强的抗氧化活性。推测脱脂米糠抗氧化活性物质富集于正丁醇萃取物。

The antioxidant crude extracts of Defatted rice bran were separated into three subfractions(ethyl acetate fraction,n-butanol fraction and aqueous fraction)by organic solvents of different polarities based on liquids-liquids extracting method.Their antioxidant activities were evaluated by Fe3+to Fe2+-reducing activity,1,1-diphenyl-2-picrylhydrazyl(DPPH)and superoxide anion free radical-scavenging assay,metal chelate ability.The results indicate that Defatted rice bran possesses powerful antioxidant ability.The n-butanol fraction have the strongest antioxidant activity;with high levels of total flavonoids content,total phenol contents,reductive activity,respectively.These results suggest that Defatted rice bran antioxidant enriched in n-butanol extract.