The results of investigation of the effect of saccharides (5% w/w) on rheological properties of modified starches were presented in this study. Three commercial modified potato starches, i.e. oxidized starch, distarch phosphate, acetylated distarch adipate, and unmodified potato starch were investigated. Glucose, fructose, sucrose and lactose were used, as well. Study of the rheological properties involved: determination of flow curves and apparent viscosity versus time curves at temperature of 50°C. Experimental flow curves were characterised by Herschel Bulkley model. Starch pastes prepared with saccharides and these without saccharides showed shear-thinning flow behaviour with tendency to yield stress. The presence of saccharides in modified starch systems, except for sucrose, resulted in higher values of flow behaviour index (n) and lower values of consistency coefficient (K) compared to values of these parameters obtained in starch-water systems. The opposite effect, i.e. an increase and a decrease of values of n and K, respectively, was observed in the case of unmodified potato starch pastes containing one of saccharides. The 5% addition of saccharides to modified starch-water systems did not influence significantly the rheological stability of obtained pastes.
modified starches, saccharides, rheological properties