pH和NaCl浓度对花椒籽仁分离蛋白乳化性的影响

摘要

The effect of pH and NaCl concentration on the properties of stabilized emulsions of Zanthoxylum bungeanum Maxim seed kernel protein isolates were investigated by measuring the characters of emulsifying activity,emulsifying stability,droplet size,optical microscopy measurements and SDS-PAGE gel electrophores.The results showed that pH and NaCl concentration have significant influence on the above parameters:with the increase of pH value,emulsifying activity and emulsion stability decreased first and then increased at pH 3.In contrast,emulsion particle size (D4,3) increased first and then decreased,and reached the maximum (D4,3 =1.87 μm) at pH 3.The NaCl content decreased the emulsifying activity and emulsifying stability,which caused the flocculation of emulsified particles and increased the average particle size (D4,3).Optical microscopy clearly demonstrated that droplet aggregates formed at pH =3 and c (NaCl) =1.2 mol/L.In addition,SDS-PAGE gel electrophoresis showed that there were three proteins having emulsifying effect,and their molecular weight was 5、7、21 kDa.This will provide reference for the application of Zanthoxylum bungeanum Maxim seed kernel protein in food processing.%以花椒籽仁分离蛋白为原料,测定不同pH和NaCl浓度条件下花椒籽仁分离蛋白的乳化活性、乳化稳定性、乳化颗粒粒径分布,并用光学显微镜观察乳化液的显微结构以及SDS-PAGE凝胶电泳检测具有乳化作用蛋白质条带.结果表明,pH和NaCl对花椒籽仁分离蛋白的乳化特性具有显著影响,随着pH值的增大,乳化活性、乳化稳定性均呈现出先减小后增大的趋势,在pH =3时都达到了最低值,具有较高的一致性;相反乳化颗粒平均粒径(D4,3)则是先增大后减小,pH =3时乳化颗粒粒径最大(D43=1.87 μm).NaCl的添加对花椒籽仁分离蛋白的乳化活性、乳化稳定性有减弱作用,促进了乳化颗粒的絮集,增大乳化颗粒的平均粒径(D4.3).通过对乳化液的显微结构观察,在pH=3和NaCl浓度达到1.2 mol/L时,乳化颗粒大且存在明显絮集现象.此外,通过SDS-PAGE凝胶电泳得出具有乳化作用的蛋白质有3个条带,分子质量分别约为5、7、21 kDa.