高甲氧基果胶对酸性大豆蛋白体系的稳定机理

为揭示高甲氧基果胶对酸性豆乳体系稳定的作用机理，通过添加不同质量浓度果胶，研究在pH值由7.0～3.0降低过程中大豆蛋白的粒径、ζ-电位以及微观结构变化。结果表明：当体系pH＜6.0时，果胶通过静电作用吸附在大豆蛋白胶粒上，阻止了大豆蛋白颗粒在酸性状态的聚集。果胶质量浓度≤0.2 g/100 mL，质量浓度1.5 g/100 mL的大豆蛋白聚集，体系失稳；果胶质量浓度≥0.4 g/100 mL，质量浓度1.5 g/100 mL的大豆蛋白体系在一定pH值内稳定，果胶质量浓度越大，稳定性越好。酸性大豆蛋白体系的稳定性与大豆蛋白和果胶之间的静电吸附作用以及果胶质量浓度有关。

Mechanism of Stabilization of Acidic Soy Protein System by High Methoxyl Pectin

The interactions of soy protein isolate with high methoxyl pectin (HMP) at various concentrations were studied
over a pH range of 7.0–3.0 to understand the stabilization mechanism of acidic soymilk system. The particle diameter,
ζ-potential and microstructure of the system during the acidification of soy protein in the presence of HMP demonstrated
that the electrostatical adsorption of HMP could take place below pH 6.0 and prevent the formation of aggregates. The acidic soy
protein system had flocculation and instability at 0.2 g/100 mL or less pectin concentration. It was stable within a certain pH range
at 0.4 g/100 mL or more pectin concentration. More pectin could result in better stability. The stability of the colloid particles at
acidic condition depended on both the electrostatical interaction of the protein with pectin and HMP concentration.