Rheological properties of Amaranthus paniculates (Rajgeera) starch vis-à-vis Maize starch

Amaranthus paniculates (Rajgeera) is abundantly available at a lower cost and hence the attempt was made in our earlier work to study the suitability of Amaranthus paniculates (Rajgeera) starch in substituting conventional thickener, Maize starch used in the printing of Indigosol (solubilised Vat) and Vat dyes on cotton. Having observed the promising performance of Rajgeera starch, it is important to know its rheological behaviour. Therefore, in the present work the effect of solid contents of thickener and the shearing time on the viscosity of paste over a wide range of shear rates has been studied. The shear thinning index (STI) and the values of viscosity at 1 rpm shear rate (i.e., K value) were used to compare the behaviour of thickeners. Keeping in mind the applicability of these two thickeners in the printing of Indigosol (solubilised Vat) and Vat dyes on cotton, their rheological properties were compared, which throw light on the print performance.