Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, Porto Alegre, RS 90040-040, Brazil.
Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, Porto Alegre, RS 90040-040, Brazil.
Carbohydr Polym. 2015 Dec 10;134:119-27. doi: 10.1016/j.carbpol.2015.07.075. Epub 2015 Jul 26.
This study focuses on the investigation of the interactions between polysaccharides (carrageenan and carboxymethylcellulose--CMC) and soy proteins from the water-soluble soy extract. The influence of pH (2-7) and protein-polysaccharide ratio (5:1-40:1) on the interaction between these polyelectrolytes was investigated in aqueous solutions with 10% of polydextrose and without polydextrose. The studied systems were analyzed in terms of pH-solubility profile of protein, ζ-potential, methylene blue-polysaccharide interactions, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and confocal laser scanning microscopy. Although the mixtures of soy extract with both carrageenan and CMC showed dependency on the pH and protein-polysaccharide ratio, they did not present the same behavior. Both polysaccharides modified the pH-solubility profile of the soy protein, shifting the pH range in which the coacervate is formed to a lower pH region with the decrease of the soy extract-polysaccharide ratio. The samples also presented detectable differences regarding to ζ-potential, DSC, FTIR and microscopy analyses. The complex formation was also detected even in a pH range where both biopolymers were net-negatively charged. The changes promoted by the presence of polydextrose were mainly detected by blue-polysaccharide interactions measures and confocal microscopy.
本研究集中于研究多糖（卡拉胶和羧甲基纤维素-CMC）与水溶性大豆提取物中的大豆蛋白之间的相互作用。在含有 10%聚右旋糖和不含有聚右旋糖的水溶液中，研究了 pH 值（2-7）和蛋白-多糖比例（5:1-40:1）对这些聚电解质相互作用的影响。从蛋白的 pH-溶解度曲线、ζ-电位、亚甲基蓝-多糖相互作用、差示扫描量热法（DSC）、傅里叶变换红外光谱（FTIR）和共聚焦激光扫描显微镜等方面对所研究的体系进行了分析。尽管大豆提取物与卡拉胶和 CMC 的混合物依赖于 pH 值和蛋白-多糖比例，但它们的行为并不相同。两种多糖均改变了大豆蛋白的 pH-溶解度曲线，随着大豆提取物-多糖比例的降低，将共沉淀物形成的 pH 范围移至较低的 pH 区域。样品在 ζ-电位、DSC、FTIR 和显微镜分析方面也表现出可检测的差异。即使在两种生物聚合物均带净负电荷的 pH 范围内，也检测到了复合物的形成。聚右旋糖存在引起的变化主要通过蓝-多糖相互作用测量和共聚焦显微镜来检测。
