Rheology of Rice‐flour Pastes: Effect of Variety, Concentration, and Temperature and Time of Cooking

Cooked pastes of rice flour showed time‐dependent shear thinning (thixotropy). Yield stresses were observed at high concentrations and high pasting temperatures. The Herschel‐Bulkley power law equation could be used with certain limitations to characterize the flow behaviour of the pastes. At low pasting temperatures (60°, 75°C), apparent viscosity increased with increasing concentration and time of cooking, and was higher for low‐amylose than for high‐amylose rice. But when cooked at 95°C, two distinct patterns were seen. At low concentrations, apparent viscosity again increased with increasing time of cooking and was higher for low‐amylose than for high‐amylose rice. But at concentrations above 7%, the pattern was totally reversed, viz., viscosity decreased with time of cooking and was higher for high‐amylose rice.