比较不同方法提取藜麦蛋白

Comparison of different extraction methods of quinoa protein

中文关键词:  藜麦  蛋白质  提取方法  抗氧化性  表征

英文关键词:quinoa  protein  extraction method  antioxidant activity  characterization

中文摘要:

      目的 比较不同方法提取藜麦蛋白的效果。方法 以藜麦为原料, 采用碱溶酸沉法、盐析法、酸提法、水提法4种方法制备藜麦蛋白, 分析其蛋白提取率、蛋白纯度、抗氧化活性和氨基酸成分, 并通过扫描电镜观察蛋白质的超微结构。结果 碱溶酸沉法的提取率最高(47.36±0.41)%, 盐析法的提取率最低(12.82±0.46)%, 但盐析法制备的蛋白纯度最高(77.75±1.16)%。酸提法制备的蛋白质外观最好, 碱溶酸沉法制备的蛋白质颜色微黄且更容易发生褐变。碱溶蛋白包含7个主条带, 酸溶蛋白和水溶蛋白的亚基组成相近, 包含5条条带, 盐溶蛋白含一个条带。藜麦蛋白质氨基酸组成平衡, 必需氨基酸含量丰富, 且藜麦蛋白具有一定的抗氧化活性。通过扫描电镜观察4种藜麦蛋白的表面结构, 碱溶酸沉法和酸提法制备的藜麦蛋白整体结构完整, 表面光滑, 结构紧密, 呈连续的聚集块状结构; 水溶法制备的藜麦蛋白, 其空间结构较为连续, 呈不规则块状, 其块状表面有些许蜂窝与孔洞; 盐析法制备的藜麦蛋白, 结构疏松, 颗粒表面粗糙, 不规则, 有小颗粒组成的微结构, 说明盐析法制备的藜麦蛋白对蛋白质的表面结构有一定程度的破坏。结论 碱溶酸沉法快速、易操作, 可为大批量制备藜麦蛋白的最佳方法。

英文摘要:

      Objective To compare the effects of different extraction methods of quinoa protein. Methods Quinoa was used as raw material to prepare quinoa protein by alkali dissolution and acid precipitation method, salting out method, acid extraction method and water extraction method. The protein extraction rate, protein purity, antioxidant activity and amino acid composition were analyzed, and the ultra structure of protein was observed by scanning electron microscope. Results The extraction rate of alkaline solution and acid precipitation method was the highest (47.36±0.41)%, and the extraction rate of salting-out method was the lowest (12.82±0.46)%, but the purity of protein prepared by salting-out method was the highest (77.75±1.16)%. The protein prepared by the acid extraction method had the best appearance, and the protein prepared by the alkali-dissolving acid precipitation method had a slightly yellow color and was more prone to browning. Alkaline-soluble protein contained 7 main bands, acid-soluble protein and water-soluble protein had similar subunit composition, including 5 bands, and salt-soluble protein contained one band. Quinoa protein had a balanced amino acid composition, rich in essential amino acids, and quinoa protein also had a certain antioxidant activity. The surface structures of 4 quinoa proteins were observed by scanning electron microscope. The quinoa proteins prepared by alkali-soluble acid precipitation method and acid extraction method had complete structure, smooth surface, compact structure, and continuous aggregated block structure. Quinoa prepared by water-soluble method Wheat protein had a continuous spatial structure and was in irregular block shape, with some honeycombs and holes on the surface of the block. The quinoa protein prepared by the salting-out method had a loose structure, rough and irregular particle surface, and had micro particles composed of small particles. The structure indicated that the quinoa protein prepared by the salting-out method had a certain degree of damage to the surface structure of the protein. Conclusion Alkali soluble acid precipitation method is fast and easy to operate, which is the best method for preparing quinoa protein in large quantities.