Abstract The influence of the salt concentration, pH, protein concentration and temperature was investigated on spontaneous reversible coacervation in soy protein isolate (SPI) solutions. Coacervation was characterized by formation of protein enriched micro-domains and was most significant at 0.1 M NaCl. It was predominant below 40 °C and favored by lowering the temperature. Decreasing the pH caused the spherical coacervates to form irregular flocs. Increasing the protein concentration led to the formation of larger coacervates, but lowered the rates of coacervation. Irreversibly crosslinked microgels were fabricated by heating suspensions of coacervates at 80 °C. The effects of the pH and the salt concentration on the morphology and the protein composition of the microgels were analyzed. The microgels swelled and displayed a core-shell structure when the electrostatic repulsion between proteins was increased by removing salt or adjusting the pH away from the isoelectric point. Reducing the electrostatic repulsion induced de-swelling of the microgels and disappearance of the core-shell structure. By tuning the electrostatic interaction, the SPI microgels could bind or release positively charged lysozyme. These results show that SPI microgels are promising bioactive compound carriers.

中文翻译：

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通过简单的大豆球蛋白凝聚制备的 pH 和离子强度响应核壳蛋白微凝胶

摘要 研究了盐浓度、pH 值、蛋白质浓度和温度对大豆分离蛋白 (SPI) 溶液中自发可逆凝聚的影响。凝聚的特征在于形成富含蛋白质的微结构域，并且在 0.1 M NaCl 时最为显着。低于 40 °C 时占主导地位，并有利于降低温度。降低 pH 值导致球形凝聚层形成不规则的絮凝体。增加蛋白质浓度导致形成更大的凝聚层，但降低了凝聚率。通过在 80°C 下加热凝聚层的悬浮液来制备不可逆交联的微凝胶。分析了pH和盐浓度对微凝胶的形态和蛋白质组成的影响。当通过去除盐分或将 pH 值调整为远离等电点来增加蛋白质之间的静电排斥时，微凝胶会膨胀并显示出核壳结构。减少静电排斥引起微凝胶的消溶胀和核壳结构的消失。通过调节静电相互作用，SPI 微凝胶可以结合或释放带正电荷的溶菌酶。这些结果表明 SPI 微凝胶是很有前途的生物活性复合载体。SPI 微凝胶可以结合或释放带正电荷的溶菌酶。这些结果表明 SPI 微凝胶是很有前途的生物活性复合载体。SPI 微凝胶可以结合或释放带正电荷的溶菌酶。这些结果表明 SPI 微凝胶是很有前途的生物活性复合载体。