Abstract: Five different fermentation broths were prepared by fermentation of purple sweet potato,red-core sweet potato,red jujube,apple juice or apple pomace by lactic acid bacteria.The total antioxidant capacity and DPPH free radical scavenging capacity of the fermentation broths and purple sweet potato vinegar were tested.Lactic acid bacteria fermentation resulted in a slight increase in the antioxidant activity of purple sweet potato.The total antioxidant capacity was increased to 200.18 mg/mL.The DPPH radical scavenging rate of fermented purple sweet potato was 96.99% at the dosage of 100 μL,which was comparable to that of purple sweet potato vinegar.Purple sweet potato fermentation broth exhibited the strongest antioxidant activity among the five fermentation broths.

Key words: purple sweet potato;lactic acid fermentation broth;DPPH free radical;total antioxidant capacity;

摘要： 测定5种乳酸发酵醪和紫甘薯醋的总抗氧化能力和对二苯代苦昧酰基（DPPH）自由基清除率，结果表明紫：甘薯乳酸发酵后抗氧化能力轻微增强，总抗氧化能力达200．18mg／mL，添加量为100μL时对DPPH自由基清除率达96．99％，与紫甘薯醋抗氧化能力相当。5种乳酸发酵醪中，紫甘薯乳酸发酵醪抗氧化能力最强。

关键词: 紫甘薯; 乳酸发酵醪; 二苯代苦味酰基(DPPH); 总抗氧化能力