通过在大豆蛋白溶液中加入高甲氧基果胶,测定其在酸化过程中大豆蛋白的平均粒径、ζ-电位以及微观结构变化,探讨果胶与大豆蛋白的作用机理,以提高酸性大豆蛋白饮品的稳定性。结果表明:果胶浓度≤0.2%,大豆蛋白胶粒在p H≥5.8时发生聚集;当果胶浓度≥0.4%时,大豆蛋白溶液在p H≤3.9时才发生聚集,果胶浓度越大,发生聚集的p H值越低。果胶通过静电作用吸附在大豆蛋白胶粒表面阻止了大豆蛋白胶粒的聚集,维持了酸性大豆蛋白体系的稳定性。

Through adding high methoxyl pectin( HMP) into soy protein isolate( SPI) solution,the changes of particle size,zeta potential and microstructure of SPI / HMP complexes were studied during acidification. The interaction mechanism of SPI at certain concentrations of HMP to improve the stability of acid soy protein beverages was discussed. The results showed that if HMP is less than 0. 2%,at p H above 5. 8 the aggregation of SPI occurred,if HMP concentration is 0. 4% or higher,the aggregation of SPI particles occurred at p H 3. 9 or less. This indicated that the higher concentration of HMP,the lower p H point would be in the aggregation. This may due to HMP absorbed onto the surface of soy protein to prevent aggregation of soy protein particles and maintain the stability of SPI solution.