黄原胶对蔗糖酯乳浊液流变特性及稳定性的影响

Effect of Xanthan Gum on the Rheological Characteristic and Stability of Sucrose Ester-stabilized Emulsion

摘要:

本文研究了黄原胶浓度对蔗糖酯溶液水力学直径DH、ζ-电势及乳浊液粒径、ζ-电势、显微结构、粘度、模量和乳析分层等指标的影响，在此基础上探讨了黄原胶对蔗糖酯乳浊液流变特性及稳定性的影响。结果表明：随着黄原胶浓度升高，蔗糖酯-黄原胶复合溶液的DH值逐渐增大，ζ-电势逐渐降低。乳浊液的粒径先增大后减小，ζ-电势没有显著的变化（p>0.05），乳浊液的粘度和模量逐渐增大。低黄原胶浓度（0~0.01 wt%）条件下，乳浊液仅出现油析分层现象；黄原胶浓度为0.05 wt%时，由于排斥絮凝作用增强，导致乳浊液的水析及油析分层最严重；随着黄原胶浓度进一步升高，由于弱凝胶网络结构的形成，一定程度提高了乳浊液的稳定性；且黄原胶浓度高于0.15 wt%时，乳浊液仅出现水析分层现象。

Abstract:

The influences of xanthan gum concentration on hydrodynamic diameter (DH), ζ-potential of sucrose ester solutions and droplet size, ζ-potential, microstructure, viscosity, modulus and creaming index of sucrose ester-stabilized emulsions were studied. The effect of xanthan gum on the rheological characteristic and stability of sucrose ester-stabilized emulsion were also investigated. The results showed that DH value of sucrose ester-xanthan gum solutions increased and ζ-potential decreased with the increase of xanthan gum concentration. ζ-potential of emulsions changed insignificantly (p > 0.05), while the droplet size increased firstly and decreased afterward, the viscosity and modulus increased with increasing xanthan gum concentration. The oil off was attributed to coalescence between fat droplets at low xanthan gum concentrations (0~0.01 wt%). The emulsion exhibited the worst stability when xanthan gum concentration was 0.05 wt% due to depletion flocculation. The stability of emulsion was improved with the increase of xanthan gum concentration due to the formation of weak gel network structure. There only existed serum phase when xanthan gum concentration was higher than 0.15 wt%.