莲子淀粉糊流变特性的研究

Rheological Properties of Lotus-Seed Starch Pastes

为探讨莲子淀粉糊及莲子淀粉-胶体体系的流变特性,使用流变仪研究了不同莲子淀粉乳浓度和添加不同亲水性胶体的莲子淀粉糊的流变特性。静态流变特性研究结果表明,莲子淀粉糊和添加胶体的莲子淀粉糊均为典型的非牛顿、时间依赖剪切变稀和触变性的流体,其流变特性曲线可用Herschel–Bulkley方程进行较好的拟合。随淀粉乳浓度和瓜尔豆胶(guar)、黄原胶(xan)添加量的增大,莲子淀粉糊的屈服应力τ0增大,而添加羧甲基纤维素(CMC)、卡拉胶(car)和海藻酸钠(alg)可使淀粉糊的流动性增强。动态流变特性研究结果表明,莲子淀粉糊储能模量(G')、损耗模量(G″)随莲子淀粉乳浓度增大而增大,且G'大于G″。添加CMC、alg能提高莲子淀粉糊的黏弹性,而添加guar和低浓度的xan、car则降低莲子淀粉糊的黏弹性。

In order to inquire into the rheological properties of lotus-seed and lotus-seed/colloidal system starch pastes, the starches have been determined by rheometer. The static rheological properties investigation estab-lished that the lotus-seed and lotus-seed/colloidal system starch pastes can exhibit typical time-dependent shear-thinning pseudoplastic and thixotropic behavior, while the Herschel-Bulkley rheological model can be used to fit the flow behavior of all starch pastes. The yield stress had increased with increasing the concentration of lotus- seed starch, guar and xan. CMC, car and alg could lead the starch paste of liquidity enhancement. The determination of dynamic rheological properties indicated that G＇ of lotus - seed starch paste was higher than G＂ and both of which were increasing synchronously with increasing the concentration. The viscoelasticity of lotus-seed paste can be im-proved by adding CMC and alg, while the viscoelasticity will decrease when adding guar and xan, car in low concen-tration.