The double helix of a polysaccharide, xanthan was unwound by heating (denaturation) and rewound by cooling (renaturation) in acidic (0.01 M HCl) and basic (0.01 M NaOH) solutions. Circular dichroism spectra of xanthan renatured in the acidic and basic solutions were similar to those of native xanthan, which suggests that the local helical structures of the renatured xanthan were recovered by renaturation. The changes in the molar mass and intrinsic viscosity of xanthan induced by renaturation in the acidic solution can be explained by the renaturation scheme in the neutral solution, as reported previously. (Matsuda et al. Polym. J. 41, 526-532, 2009). Both the molar mass and radius of gyration of xanthan in the basic solution were decreased by denaturation and renaturation, and the molar mass dependence of the radius of gyration was similar to that of native xanthan. This change can be explained by the formation of a hairpin structure during renaturation in the basic solutions.

多糖黄原胶的双螺旋在酸性 (0.01 M HCl) 和碱性 (0.01 M NaOH) 溶液中通过加热（变性）解开并通过冷却（复性）重新缠绕。在酸性和碱性溶液中复性的黄原胶的圆二色光谱与天然黄原胶的圆二色光谱相似，这表明复性黄原胶的局部螺旋结构通过复性得以恢复。如前所述，酸性溶液中复性引起的黄原胶摩尔质量和特性粘度的变化可以通过中性溶液中的复性方案来解释。 (Matsuda 等人Polym. J. 41 , 526-532, 2009)。碱性溶液中黄原胶的摩尔质量和回转半径均因变性和复性而降低，并且回转半径的摩尔质量依赖性与天然黄原胶相似。这种变化可以通过基本溶液复性过程中发夹结构的形成来解释。