大豆分离蛋白及其与丙烯酸接枝产物在不同pH值水相中的动态光散射研究

Study on the effect of pH value on the solution of soybean protein isolate and its grafted copolymer with acrylic acid based on dynamic light scattering

利用动态光散射技术，研究了大豆分离蛋白及其与丙烯酸接枝共聚物在水相体系中对pH值的响应性。结果发现，大豆分离蛋白和接枝产物对水相pH值都具有很高的响应性。大豆分离蛋白平均流体力学半径〈Rh〉在等电点附近（pH=4～5）达到最大值。接枝率为27．5％的丙烯酸的接枝共聚物的平均流体力学半径〈Rn〉在pH为2～3范围内最大。随着接枝率增加，丙烯酸的接枝共聚物在水相体系中的溶解性能越好。对接枝产物不同pH值水溶液进行研究具有很大的理论指导意义。

In this paper,the effect of pH value on the solution behavior of soybean protein isolate （SPI） and its grafted copolymer with acrylic acid （SPI-g-PAA） was investigated by dynamic light scattering （DLS）. The results indicated that the radius of SPI and SPI-g-PAA aggregates was related to the pH values. The average hydrodynamic radius of SPI aggregate had the maximum value at its isoelectric point （pH =4～5）. The average hydrodynamic radius of SPI-g-PAA aggregates with the 27.5% grafting rate had the maximum at pH = 2 ～ 3. The solubility of the SPI-g-PAA in aqueous solution increased with increasing of the grafting rate.