超声波辅助碱法提取黑木耳蛋白质及其性质研究

Ultrasonic-assisted alkaline extraction and properties of Auricularia auricular protein

目的研究黑木耳蛋白的结构和性质,为黑木耳蛋白的应用提供一定的理论基础。方法以干黑木耳粉末为原料,通过超声波辅助碱法提取黑木耳蛋白质。采用氨基酸分析仪和圆二色光谱仪测定黑木耳蛋白质中氨基酸和二级结构的含量。聚丙烯酰胺凝胶电泳和差示扫描量热仪测定黑木耳蛋白质的亚甲基分子量和热变性温度。结果最佳工艺条件为:提取pH值11.0,超声时间20 min,超声功率200 W,此时提取率为66.32%。确定了黑木耳蛋白质中氨基酸的总量达到824.5 mg/g,必需氨基酸可达到361.0 mg/g;黑木耳蛋白质的二级结构的含量为α-螺旋18.3%,β-折叠40.4%,β-转角14.0%,无规则卷曲27.3%;黑木耳蛋白质亚基分子量的分布范围为13.5 kDa^91.4。kDa,主要有9个条带;黑木耳蛋白质的热变性温度(92.91℃)高于大豆蛋白质(74.57℃和90.52℃)。结论黑木耳蛋白质是一种营养全面、热稳定性高的蛋白质。

Objective The structure and property of Auricularia auricular protein were investigated preliminarily to provide a theoretical basis for the application. Methods The dried Auricularia auricular powder was used as the raw material. Auricularia auricular protein was extracted by ultrasonic assisted alkali distillation. Amino acids and secondary structure of the Auricularia auricular protein were detected by amino acid analyzer and circular dichroism spectrometer. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and differential scanning calorimetry (DSC) were applied to detect methylene molecular weight and thermal denaturation temperature. Results The orthogonal experiment results showed that:pH was 11.0, ultrasonic time was 20 min, and ultrasonic power was 200 W. Under these best conditions, the extraction rate of Auricularia auricular protein could reach to 66.32%.The results showed that amino acids content contained in Auricularia auricular protein was 824.5 mg/g, essential amino acids were 361.0 mg/g. The content of secondary structure of Auricularia auricular protein was:α-helix 18.3%,β-folding 40.4%,β-corner 14.0%, and random coil 27.3%. The molecular weight of its subunits were mainly 9 bands and its range was 13.5 kDa^91.4 kDa. The thermal denaturation temperature of Auricularia auricular protein (92.91℃) was higher than that of soy protein (74.57℃and 90.52℃). Conclusion Auricularia auricular protein is a kind of comprehensive and high thermal stability protein.