蚕豆蛋白的提取及NaCl浓度和pH值对其溶解性和乳化性的影响

蚕豆蛋白富含微量元素和人体必需的8种氨基酸，具有较高的开发价值。采用超声提取和水提取的方法提取蚕豆蛋白，研究了NaCl浓度和pH对蚕豆蛋白提取率、沉淀、功能性的影响。在pH值为8～12，超声提取和水提取均有较高的提取率。蚕豆蛋白的等电点在pH4.0～4.2之间。在pH4溶解性和乳化性最低，pH值在4～12时溶解性和乳化性随pH值的升高而升高， pH值为12时溶解性和乳化性最高。NaCl浓度从0 到 1.0 mol/L，溶解性和乳化性升高；当NaCl浓度继续增加，在pH 4、pH 7溶解性和乳化性随之下降。在相同的NaCl浓度和pH值时，超声提取比水提取蛋白的溶解性和乳化性高。该研究为蚕豆蛋白的提取工艺的确定及其在食品中的应用提供依据。

Extraction of broad bean protein and effects of NaCl concentration and pH value on its solubility and emulsibility

Broad bean protein, with the eight essential amino acids and high levels of trace elements, is valuable for development. This work was aimed to investigate the suitability of water extraction and a method i.e ultrasonic method for extraction of broad bean protein and to study its functional properties. Broad bean protein was prepared from broad bean and the extraction rate, precipitation and functional properties of broad bean protein were investigated under the influence of variable ranges of pH value and NaCl concentration. The maximum yield of extractable protein, both by ultrasonic and water extraction methods could be achieved at the range of pH value 8-12. The isoelectric point of broad bean protein was found to be at pH 4.0-4.2. Solubility and emulsification of the protein increased, as the pH value increased from 4 to 12, with the least solubility and emulsification of protein at pH 4 and the maximum at pH 12. The solubility and emulsification of broad bean protein increased in NaCl as concentration increased from 0 to 1.0 mol/L, while further increase of NaCl concentration caused solubility and emulsification of the protein to decline both at pH 4 and pH 7. So the ultrasonic assisted extraction resulted in higher solubility and emulsification of protein than those by water extraction at the same pH value and NaCl concentration. This result with the protein extraction process and the influence of some?extracting factors lay the foundation for the development and utilization of broad bean protein.