Colour Characteristics and Overall Acceptability of Fibre Enriched Biscuits: A Response Surface Approach

The effects of baking time and baking temperature on colour (L*a*b*), colour difference (Delta E) and overall acceptability (OAA) of biscuits made from different blends of refined wheat flour (RWF) and millet was investigated using a three factor central composite rotatable design (CCRD). ANOVA for response surface model demonstrated that the data could fit the three polynomial models adequately. All the models were found to be statistically sound to predict the responses. The colour values and OAA were significantly influenced by the processing variables at different levels of significance. The blend ratio, percent RWF, was found to have an overwhelming effect on all the colour values and OAA. It was predicted that the optimum product colour characteristics in terms of L*(29.45), a*(-105.01), b*(-92.7), Delta E (11.9) and OAA (6.3) were obtained at blend ratio, 70 percent RWF; baking time, 5.6 min; and baking temperature, 171.7 degrees C.