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紫苏是一种珍贵的药食两用植物。为确定紫苏叶黄酮类物质的微波提取工艺,分析其抗氧化活性,采用动量梯度下降神经网络研究微波功率、乙醇体积分数、料液比和提取时间对黄酮提取率的影响,对反应条件进行训练仿真和网络预测。采用DPPH·自由基、羟自由基、超氧阴离子和ABTS+·自由基比较分析紫苏叶的水、醇提取物的抗氧化性质。研究结果表明:经过训练的网络可以很好地模拟微波提取条件,当微波功率480W,乙醇体积分数80%,固液比1:25g/mL,提取时间25min时,黄酮提取率达6.2mg/g。随着提取物浓度的增大,清除自由基能力增强。高含量(0.5mL/mL)的紫苏叶醇提物具有良好的清除自由基能力,清除率90%以上。叶水提物对自由基清除能力较差,在其含量为0.5mL/mL时,对DPPH自由基的清除率仅36%。
Perilla is a precious edible plant. In order to determine the extraction technology of flavonoids from Perilla frutescens leaves, the antioxidant activity was analyzed. The influence of microwave power, ethanol volume fraction, solid-liquid ratio and extraction time on the extraction rate of flavonoids was studied by using the momentum gradient descending neural network. Training Simulation and Network Prediction. The antioxidant properties of water and alcohol extract from Perilla frutescens leaves were compared by DPPH · free radical, hydroxyl radical, superoxide anion and ABTS + · radical. The results showed that the microwave extraction conditions were well simulated by the trained network. The extraction rate of flavonoids reached to 6.2 mg / g at microwave power of 480W, ethanol volume fraction of 80%, solid-liquid ratio of 1:25 g / mL and extraction time of 25 min . As the extract concentration increases, the ability to scavenge free radicals increases. High content (0.5mL / mL) perilla leaf alcohol extract has a good free radical scavenging capacity, clearance rate of 90% or more. Leaf water extract on the scavenging capacity of free radicals at its content of 0.5mL / mL, DPPH radical scavenging rate of only 36%.