The effect of extruded flour and fermentation time on some quality parameters of idli

The effects on idli characteristics of fermentation time and substituting r ice with differing proportions of rice flour extrusion-cooked under differe nt conditions were studied The specific gravity, pH and viscosity of batter and idli characteristics such as expansion, compression force and sensory attributes were measured and described using regression to fit a response s urface analysis. Fermentation time showed the most pronounced effect on spe cific gravity, pH and aqueous dispersion viscosity of batter and taste scor es of idli. Substituting rice flour with extruded rice flour at different l evels were observed to have significant effect on expansion and appearance scores of idlis. The textural scores and compression force was significantl y affected by extrusion temperature. The formulation containing rice substi tuted by 30% extruded rice flour extruded at 175C and fermented for 24 h pr oduced idlis with highest expansion and overall acceptability.