蔗糖共溶质对琼脂-魔芋胶共混体系溶胶-凝胶转变过程流变学性质及结构形成动力学的影响

以琼脂-魔芋胶溶液共混体系为研究对象，考察添加蔗糖共溶质（质量分数0%、5%、10%、15%）对溶胶-凝胶转变过程弹性模量（G’）和黏性模量（G”）变化的影响，并通过对凝胶结构平均形成速度（average structure development rate，SDRa）、即时凝胶化速度（vg）、凝胶化加速度（αg）分析，探讨凝胶结构形成动力学。结果表明：低质量分数（0%～5%）蔗糖共溶质存在时可显著提高共混体系的G’、SDRa、vg及αg（P＜0.05），共溶质质量分数高于5%后，此4 个特征值被降低。低质量分数蔗糖共溶质通过增加共混体系中琼脂分子间的氢键作用，促进琼脂分子形成双螺旋结构，显著降低高温区的活化能，进而交联形成细密、平整的网络结构，改善了共混体系凝胶的流变及质构凝胶特性。

Effects of Sucrose Addition as Cosolute on the Rheological Properties and Structure Formation Kinetics of Agar/Konjac Blends during Sol-Gel Transition

The effects of sucrose addition as a cosolute (0%, 5%, 10%, and 15%) on the evolution of the elastic modulus (G’) and viscous modulus (G”) of agar/konjac blends during sol-gel transition were investigated. The kinetics of structure formation was explored by analyzing the average rate of gel structure development (SDRa), instant gelation velocity (vg) and gelation acceleration (αg). The results showed that the G’, SDRa, vg and αg of agar/konjac blends were increased significantly with sucrose concentration up to 5% (P < 0.05) and then decreased. Addition of low concentration of sucrose could promote the agar intermolecular hydrogen bonding interaction of agar/konjac blends and induce the double helix formation of agar molecules. Consequently the rheological and textural properties of agar/konjac blend gels were improved by significantly reducing the gelation activation energy (Ea) in the high temperature scope and promoting the formation of compact and flat three-dimensional network microstructure.