Rheological properties of gelatinized chestnut starch dispersions: Effect of concentration and temperature
Rheological properties of gelatinized chestnut starch dispersions at different concentrations (4.0, 5.0, 6.0 and 7.0% w/w) and temperatures (25, 40, 55 and 70 °C) were experimentally determined using a controlled stress rheometer under steady shear (shear rate: 1–500 s−1) and oscillatory (angular frequency: 2–70 rad/s) tests. Starch dispersions showed shear-thinning behavior. Flow curves were successfully fitted to Herschel–Bulkley model and the corresponding parameters were correlated with temperature and starch concentration. Mechanical spectra revealed behavior like gel for all tested starch dispersions. Oscillatory data were satisfactorily fitted by power law model. Cox-Merz rule was not fully satisfied, particularly at low shear rates/angular frequencies, because dispersions showed apparent viscosity values lower than complex viscosity values. âº We studied the rheological properties of chestnut starch dispersions. âº Shear-thinning behavior was observed at each temperature and starch concentration. âº Weak gel characteristics by means of frequency sweeps in the LVR were determined. âº Dispersions with concentration above 6.0% showed particular trend with temperature.