Starch is synthesized in intracellular structures called amyloplasts, whose wraps delimiting the organelle are referred to as plastid membranes. Such envelopes are generally removed in the industrial processing of cereal starches, but not of cassava starch (CS), which is submitted to a different process. The occurrence of different rheological behaviors before a shear thickening (ST) event for granular starch suspensions is well known, but not yet thoroughly explained. The objective of this work was to study physical changes on commercial CS suspensions that could intensify their shear thickening properties when glycerol is used as a solvent. The results show that the removal of plastid envelopes from starch granules significantly reduces its deformable character in glycerol suspensions. It intensifies the delayed ST behavior and maintains the flow stability during an eventual discontinuous ST transition, provided that suspensions are conditioned at an adequate relative humidity (close to 43%). Experimental data also have suggested an explanation for why a Newtonian or a shear-thinning behavior precedes shear thickening in starch suspensions.

淀粉在称为淀粉质体的细胞内结构中合成，其包裹细胞器的包裹层称为质体膜。通常在谷物淀粉的工业加工中除去这种包膜，但是在木薯淀粉（CS）的工业加工过程中不除去这种包膜，而将木薯淀粉进行另外的加工。对于颗粒状淀粉悬浮液，在剪切增稠（ST）事件发生之前，会发生不同的流变行为，这是众所周知的，但尚未完全解释。这项工作的目的是研究商品CS悬浮液的物理变化，当甘油用作溶剂时，这些变化可能会增强其剪切增稠性能。结果表明，从淀粉颗粒中去除质体包膜可显着降低其在甘油悬浮液中的可变形性。如果悬浮液在足够的相对湿度（接近43％）下调节，它会增强ST的延迟行为并在最终的非连续ST过渡过程中保持流动稳定性。实验数据还提出了为什么在淀粉悬浮液中牛顿或剪切稀化行为先于剪切增稠的解释。