Rheological analysis of dough prepared with lentil flour at different moistures for production of extruded products

Extruded products like expanded puff product are prepared from lentil ( Lens culinaris Medik ) at different conditioning moisture (14, 18, 22 %) for constant temperatures, range from 100 to 210 °C, which was used during extrusion processing. The present study was aimed to investigate the effect of conditioning moisture at different temperature on the rheological behavior of lentil. It was determined that viscosity and yield stress of the lentil dough decreased with increase in conditioning moisture of flour used during extrusion process. Yield stress decreased by 68 and 80 % for conditioning moisture at 18 and 22 %, respectively as compared to those conditioning moisture at 14 %. This was attributed to the changes in the carbohydrates occur due to high extrusion temperature. Increasing the conditioning moisture during extrusion process decreased the fluid consistency index and increased the flow behavior index of the dough, demonstrating a lower viscosity and increased fluidity. All the samples revealed shear thinning behavior. The dough prepared using lentil shows depletion in gelatinization temperature with decreased in conditioning moisture as demonstrated by viscoelastic analysis (loss modulus, storage modulus, Tan δ) of the samples.