摘要:本课题是以紫薯为原料，以料水比、乳酸菌接种量、发酵温度为单因素做实验，以紫薯酸度、营养特性和抗氧化活性的变化为指标，进而通过正交试验得出乳酸菌发酵紫薯的最优方案：料水比为1:3，接种量为6%，发酵温度为40℃。在最优方案条件下，测定乳酸菌发酵过程中紫薯总糖、游离氨基酸、可溶性蛋白、花青素、羟基自由基清除能力的变化，以探究紫薯在发酵期间营养特性和抗氧化活性的变化规律。实验结果显示：最优方案条件下，经过14h的发酵，总糖含量从154.34 mg/mL明显降低到 14.68mg/mL，游离氨基酸、可溶性蛋白和花青素含量均先升后降，与未发酵相比，游离氨基酸含量由15.55ug/mL下降到 8.69ug/mL，可溶性蛋白含量略有上升，从1.235%上升到1.474%，花青素含量从0.936 ug/mL下降到0.606 ug/mL；羟基自由基的清除率从55.00%上升到83.33%，紫薯抗氧化活性得到了提高。

关键词 紫薯；乳酸菌发酵；营养特性；抗氧化活性

Abstract:This topic is based on purple potato as raw material, with the ratio of material to water, quantity of lactic acid bacteria, fermentation temperature as three single factor for experiment, with purple potato acidity, nutritional characteristics, and the change of antioxidant activity as an index, and through the orthogonal experiment of lactic acid bacteria fermentation purple potato optimal solution: material to water ratio of 1:3, inoculation quantity is 6%, the fermentation temperature of 40 ℃. Under the condition of the optimal scheme, determination of purple potato in lactic acid bacteria fermentation, total sugar, free amino acid, soluble protein, anthocyanins, hydroxyl radical scavenging ability of change, in order to explore the purple potato nutritional characteristics, change rule of antioxidant activity during the fermentation. Experimental results showed that: under the condition of the optimal solution, after 14h fermentation, from 154.34 mg/mL total sugar content significantly decreased to 14.68 mg/mL, free amino acid, anthocyanins and soluble protein content are rising before fall, compared with unleavened, free amino acid content by 15.55μg/mL, down to 8.69μg/mL, soluble protein content increased slightly, from 1.235% to 1.474%, the anthocyanins content in decreased from 0.936μg/mL to 0.606μg/mL. The hydroxyl free radical clearance rate increased from 55.00% to 83.33%, the fermentation could improve the antioxidant activity of purple potato.

Keywords  Purple potato  Lactic acid bacteria fermentation  Property  Antioxidant activity