The response surface method (RSM) was used to optimize the ultrosonic extraction process of polysaccharides from Lobaria kurokauae Yoshim.Crude polysaccarides were further processed by decoloration,deproteinization with sevage method and DEAE-52 ion-exchange column choromatography to obtain three components LKY-Ⅰ,LKY-Ⅱ and LKY-Ⅲ.The molecular mass and purifity of the three components were identified by gel permeation chromatography and Sephadex G-100 gel column chromatography;the physico-chemical properties were also determined by iodine-potassiumiodide,phenol-sulphuric acid,coomassie brilliant blue G-250,and sulfuric acid-carbazole method;and the antioxidant activity of LKY-Ⅰ,LKY-Ⅱ and LKY-Ⅲ were evaluated by determining the DPPH and ABTS+ free radicals scavenging rate as well as the reducing power.Results showed that the optimum polysaccharide extraction conditions were as follows:power 800 W,extraction time 15 minutes,and liquid-to-material ratio 25∶1,and the polysaccharide yield reached 4.39％.The molecular masses of LKY-Ⅰ,LKY-Ⅱ and LKY-Ⅲ were 61 598 Da,122 495 Da and 697 243 Da;the total sugar content were 88.91％,74.05％ and 59.18％;the uronic acid content were 13.21％,15.12％ and 16.02％,and the protein content were 0.13％,0.46％ and 0.91％,respectivley;and the three kinds of polysaccarides LKY-Ⅰ,LKY-Ⅱ and LKY-Ⅲ did not contain soluble starch and nucleic acid.Antioxidant activity tests showed that the polysaccaride samples had high antioxidant activity in 0.25 to 10 mg/mL.%以树蝴蝶为原料,通过响应面分析获得超声辅助提取的最佳工艺.粗多糖通过脱色,除蛋白和DEAE-52柱层析得到LKY-Ⅰ、LKY-Ⅱ、LKY-Ⅲ 3种纯化多糖;通过GPC结合SephadexG-100鉴定其分子质量及纯度,利用I2-KI、苯酚-硫酸、考马斯亮蓝G-250、硫酸-咔唑法测定其理化性质;通过测定DPPH、ABTS+自由基清除率及还原力评价LKY-Ⅰ、LKY-Ⅱ、LKY-Ⅲ的抗氧化能力.根据响应面分析,得到多糖提取最佳工艺为:功率80 W、时间15 min、液料比25∶1,此时得率为4.39％.LKY-Ⅰ、LKY-Ⅱ、LKY-Ⅲ分子质量分别为61 598、122 495、697 243u;总糖含量分别为88.91％、74.05％、59.18％;糖醛酸含量分别为:13.21％、15.12％、16.02％;蛋白含量分别为0.13％、0.46％、0.91％;3种多糖不含可溶性淀粉和核酸.研究表明,多糖样品在0.25～10 mg/mL范围内均具有较强的抗氧化活性,说明树蝴蝶纯化多糖具有一定的抗氧化活性.
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