College of Food Science, Southwest University, Chongqing, 400715, PR China; Chongqing Key Laboratory of Chinese Medicine & Health Science, Chongqing Academy of Chinese Materia Medica, Chongqing, 400065, PR China.
College of Food Science, Southwest University, Chongqing, 400715, PR China.
Carbohydr Polym. 2020 Jun 1;237:116115. doi: 10.1016/j.carbpol.2020.116115. Epub 2020 Mar 6.
Environmental temperature and pH induced significant changes in the size and surface charge (ζ) of octenylsuccinated oat β-glucan aggregates. The underlying mechanisms were explored by using H-NMR, fluorescence spectra, thermodynamic analysis, and SAXS. At pH 6.5, the size decreased with temperature while ζ continuously increased. With increasing pH at 293 K, parabolic and U-shaped trends were observed in the size and ζ, peaking at pH 8.5 and 6.5, respectively. At any tested pH, the size decreased with temperature. Overall, ζ significantly increased with temperature at each pH. As temperature increased, the compactness of hydrophobic-domains increased while the compactness of hydrophilic-domains decreased. In an acidic environment, both the compactness increased with decreasing pH, but in an alkaline environment, they decreased with pH. The compactness changes were co-driven by enthalpy and entropy and corresponded to changes in the hydrophobic interactions in hydrophobic-domains, hydrogen bonds in hydrophilic-domains and electrostatic repulsions among octenylsuccinate molecules.
环境温度和 pH 值会引起辛酰琥珀酸燕麦 β-葡聚糖聚集物的大小和表面电荷（ζ）发生显著变化。通过使用 H-NMR、荧光光谱、热力学分析和 SAXS 来探索其潜在机制。在 pH 值为 6.5 时，随着温度的升高，大小减小，而 ζ 值持续增加。在 293 K 时，随着 pH 值的增加，大小和 ζ 值呈现抛物线和 U 型趋势，分别在 pH 值为 8.5 和 6.5 时达到峰值。在任何测试的 pH 值下，大小随温度的升高而减小。总体而言，在每个 pH 值下，ζ 值随温度的升高而显著增加。随着温度的升高，疏水区的紧凑度增加，而亲水区的紧凑度降低。在酸性环境中，随着 pH 值的降低，两者的紧凑度都增加，但在碱性环境中，随着 pH 值的增加，它们的紧凑度降低。这种紧凑度的变化是由焓和熵共同驱动的，与疏水区中的疏水相互作用、亲水区中的氢键以及辛酰琥珀酸盐分子之间的静电斥力的变化相对应。
