Process parameter optimization in relation to some sensory attributes of millet flour enriched biscuits using response surface methodology (RSM)

Abstract

Designed experiments were conducted to study the effect of varying baking time (3.3–6.7 min) and baking temperature (166.6–183.4 °C) upon biscuits made out of five blends of refined wheat flour (RWF) and millet flour (63.2–96.8% RWF). The sensory attributes of the biscuits were evaluated in terms of crispness, colour (L* and ΔE) and overall acceptability (OAA). Response surface methodology (RSM) was used to develop models and optimize the processing parameters. The blend ratio had a predominant effect upon all the responses. Crispness and ΔE were found to have maximum sensitivity towards all the processing parameters. The optimum processing condition obtained was blend ratio 90% RWF, baking time 6 min and baking temperature 170 °C, predicted values of crispness, L*, ΔE and OAA were 44, 34.3, 14.38 and 7.9, respectively. The model predicted values did not significantly differ from experimental values.