[关键词]
[摘要]
本文研究大豆蛋白组成(不同配比7S和11S蛋白)对水包油型乳液乳化和界面吸附特性的作用规律。结果表明:自提7S和11S球蛋白基本处于天然未变性状态;随着大豆蛋白中11S含量的增加,乳液整体粒径分布增大,乳液乳化活性指数、ζ电位绝对值、油水界面蛋白浓度及含量均逐渐减少,乳滴絮凝和合并指数显著上升,乳液整体乳化活性及稳定性也随之降低;由乳化特性数据可知7S球蛋白对大豆蛋白整体乳化性能贡献大于11S;界面蛋白电泳结果表明所有亚基均可吸附至界面,且吸附的两类蛋白各亚基含量变化与各样品蛋白所占比重基本一致;乳液微结构随着11S球蛋白含量提升由清晰球状转变为无规则絮凝聚集态;整体上本实验所提大豆11S球蛋白在油水界面扩散、展开和重排速率高于7S球蛋白,不同11S含量的大豆蛋白界面重排速率均高于吸附展开速率,通过调整大豆蛋白组成可一定程度上调控蛋白在乳液界面吸附行为。
[Key word]
[Abstract]
The effect of soybean protein composition (different ratios of 7S globulin (β-conglycinin) and 11S globulin (glycinin)) on the emulsifying and interfacial properties of oil-in-water (O/W) emulsions was evaluated. The results indicated that manually extracted 7S and 11S globulins were in their native state. With increasing 11S content, the emulsifying activity index, absolute value of ζ-potential, protein concentration, content at the O/W interface, emulsifying activity, and stability were reduced, and the overall particle size distribution, droplet flocculation index, and droplet coalescence index of the emulsion were increased. According to the results of emulsifying properties, 7S globulin contributed more towards the overall emulsification ability of soybean proteins than the 11S globulin did. Electrophoresis images of interfacial proteins indicated that all subunits of the two globulins could be adsorbed at the O/W interface, and changes in the contents of all subunits were in accordance with the proportion of proteins in the sample. With increasing 11S content, the emulsion microstructure changed from a clear spherical shape into irregularly flocculated aggregates. In general, diffusion, adsorption, and rearrangement rates of the 11S globulin at O/W interface were higher than that of 7S globulin, and the rearrangement rates of all protein samples with different 11S contents at O/W interface were higher than the adsorption rates. These results suggest that emulsifying and interfacial adsorption properties of soybean globulins can be regulated to some extent by altering the protein composition.
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[基金项目]
国家自然科学基金资助项目(31471695,31171632)