梨膏的流变学特性及其影响因素

目的 考察人为加糖、加胶后梨膏触变性及黏度的变化。方法 以鸭梨为实验材料,通过真空浓缩方式制备鸭梨膏,采用HR-10型流变仪对其流体类型、黏度、触变性进行测定。结果 鸭梨膏属于非牛顿流体,具体细分为无限接近牛顿流体的假塑性流体,具有剪切稀化特性和正触变特性;损耗模量G″总是大于储能模量G’,表现出液体黏性性质;剪切速率与剪切力变化关系符合PowerLaw方程,拟合效果良好(r2>0.99);温度显著影响梨膏黏度,黏度随温度升高而降低,二者关系符合Arrhenius方程,拟合效果良好(r2>0.99);可溶性固形物含量(solublesolidscontent,SSC)对黏度的影响符合指数函数关系,模型拟合效果良好(r2>0.99);SSC以及人为加糖、加胶处理对梨膏触变性、黏度影响显著(P<0.05),黏度随SSC的升高而增强,人为加胶、加糖加胶会导致梨膏黏度显著升高(P<0.05);触变性随SSC的升高而增强,同时人为加糖、加胶、加糖加胶处理会导致梨膏触变性显著减弱(P<0.05)。结论 人为添加糖、胶会导致梨膏的流变学特性发生改变。本研究可为工业...

Rheological properties of pear paste and its influencing factors

Objective To investigate the thixotropy and viscosity changes of pear paste after artificial addition of sugar and gum. Methods Yali pear paste was prepared by vacuum concentration using Yali pear was used as the experimental material, the fluid type, viscosity and thixotropy of it were determined by HR-10 rheometer. Results Yali pear paste belonged to non-Newtonian fluid, which was subdivided into pseudoplastic fluid infinitely closed to Newtonian fluid, with shear thinning and normal thixotropy characteristics. The loss modulus G" was always greater than the storage modulus G'', which showed the viscous property of the liquid. The relation between shear rate and shear force fitted the Power Law equation, and the fitting effect was gorgeous (r2>0.99). Temperatures significantly affected the viscosity of pear paste, the viscosity decreased with increasing temperature, which conformed to the Arrhenius equatione, and the fitting effect was good (r2>0.99). The effect of soluble solids content (SSC) and viscosity presented exponential function, and good model fitting effect (r2>0.99). The thixotropy and viscosity of pear paste were significantly affected by SSC, artificial addition of sugar and glue (P<0.05). The viscosity increased with the increase of SSC, and tartificial addition of sugar and glue caused the viscosity of the pear paste to increase significantly (P<0.05). Thixotropy of pear paste was enhanced with the increase of SSC, while the thixotropy of pear paste was significantly weakened by artificial addition of sugar, glue and sugar and glue (P<0.05). Conclusion The artificial addition of sugar and glue will change the rheology properties of pear paste. This study can provide a new idea for the quality improvement and quality control of pear paste products in industrial production, and provide a theoretical basis for the research of rheological properties of pear paste.