黄原胶体系的流变性及糖和盐对体系的影响

Rheological Study of Aqueous Solutions and Emulsions Containing Xanthan

报道了对黄原胶水溶液以及以黄原胶水溶液为水相的２０％（Ｏ／Ｗ体积分数）乳状液在３０℃的流变学性质的研究。实验中通过振荡和蠕变测试考察了从０．０５％～０．５％系列质量分数的黄原胶溶液和乳状液的流变学性质以及０．５ｍｏｌ／ＬＮａＣｌ和质量分数１０％的蔗糖对这些体系的影响。发现，随着黄原胶质量分数的增加，体系逐渐表现固态的反应，这表明大分子交联或其它方式的缔合逐渐提高了体系结构化的程度。蔗糖的存在在一定程度上增强了大分子的这种功能作用，而ＮａＣｌ的引入则明显降低了大分子的这种影响，并且ＮａＣｌ的这种影响对黄原胶质量分数较高的体系更加明显。乳状液体系的测定结果与水相的情况一致。

This paper reports the studies into the viscoelasticity of the aqueous solutions and 20% O/W emulsions containing xanthan. The elastic response of the systems to smalldeformation was measured by using the techniques of mechanical spectroscopy under 30℃ and the effects of 0.5 mol/L NaCl or/and 10% sucrose on the rheology of the systems were investigated as well. Results reveal that the xanthan enhanced stability of emulsions is correspond to a predominantly 'solidlike' viscoelasticity of both the aqueous phase and the emulsion. The introduction of a certain concentrations of xanthan to the aqueous solution gives rise to the formation of a structured system with a high elastic response to the deformation. The storage modulus of the aqueous solutions containing xanthan can be slightly increased by sucrose. Nevertheless, the present of NaCl leads to a decrease in the storage modulus and makes the systems more 'liquidlike'.