分蘖葱头蛋白提取工艺优化及其基础特性

摘要

采用碱溶酸沉正交法对分蘖葱头中蛋白质进行提取工艺优化,并对其基础特性进行测定,结果表明在料液比1:15 (g/mL)、pH 9.0、提取温度50℃、提取时间1.5h条件下提取率最大为79.38％.电泳结果表明蛋白分子质量分别为61.94、27.10、17.62、13.34 kDa.高效液相色谱法测得分蘖葱头蛋白中必需氨基酸质量分数为38.96％,非必需氨基酸质量分数为61.04％.二级结构测定结果表明分蘖葱头蛋白中α-螺旋含量为52.60％,β-折叠含量为8.60％,β-转角含量为15.60％,无规则卷曲含量为22.40％.采用红外图谱法对分蘖葱头蛋白特征官能团进行测定,其特征官能团明显.%The extraction of protein from Allium cepa L.var.agrogatum Don by alkali dissolution and acid precipitation was optimized using orthogonal array design method.Along with this,the extracted protein was also characterized.The results showed that the maximum extraction efficiency of protein of 79.38％ was obtained after extraction at 50 ℃ and pH 9.0 with a solid-to-solvent ratio of 1∶15 (g/mL) for 1.5 h.HPLC analysis demonstrated that the protein consisted of 38.96％ essential amino acids and 61.04％ non-essential amino acids.Electrophoresis showed that the protein was composed of four components with molecular weights of 61.94,27.10,17.62,and 13.34 kDa.The secondary structure consisted of 52.60％ a-helix,8.60％ β-sheet,15.60％ β-turn and 22.40％ random coil.The characteristic functional groups of the protein were confirmed by infrared spectroscopy.