圆苞车前子壳胶的流变特性

The rheological properties of psyllium husk gum

圆苞车前子壳是膳食纤维的良好来源,对其形成的凝胶进行微观观察,并进行稳态剪切及动态振荡试验,以研究质量浓度、剪切力、pH、温度、盐对圆苞车前子壳胶(psyllium husk gum,PHG)流变特性的影响。扫描电镜及激光共聚焦显微镜结果显示,PHG的微观结构呈现带褶皱的片状,具有较多的不规则间隙和孔洞。流变测试结果表明,PHG是弱凝胶(G′>G″),也是具有低触变性的假塑性流体,具有较高的黏性,其流动曲线符合Herschel-Bulkley模型(r^(2)=0.997)。PHG的流变特性受不同加工条件的影响,具体表现为:质量浓度越高,凝胶结构越强;在pH 4.0~10.0范围内提高pH,可增加假塑性;PHG在温度5~85℃具有较好的热稳定性;盐离子的引入可以增加PHG的结构稳定性。试验结果和模型为PHG在食品工业中的研发提供理论基础,促进这一新食品原料的开发应用。

Psyllium husk is rich in dietary fiber.In this study,the microscopic observation of the gel formed by the psyllium husk and the steady-state shear and dynamic oscillation tests were carried out to study the effects of concentration,shear force,pH,temperature,and salt on the rheological properties of psyllium husk gum(PHG).Scanning electron microscopy and laser confocal microscopy showed that the microstructure of PHG were folded and had more irregular gaps and holes.The results of rheological test showed that PHG was a weak gel(G′>G″),a pseudoplastic fluid with low thixotropy and had a high viscosity.The flow curve was conformed to the Herschel-Bulkley model(r^(2)=0.997).The rheological properties of PHG were affected by different processing conditions which showed that the higher the concentration,the stronger the gel structure;pseudo-plasticity was increased with the increasing of the pH in the range of 4.0-10.0.Moreover,the PHG had good thermal stability in the range of 5-85℃and the introduction of ions increased the structural stability of PHG.The results and models will provide a theoretical basis for PHG′s research and development in the food industry.It couldpromote the development and application of this new food material.