Study on the effects of smooth roll grinding conditions on reduction of wheat middlings using response surface methodology

Influence of the milling parameters on the reduction process of the wheat middlings by the smooth rolls was investigated. Three level and four variables Box–Behnken experimental design with response surface methodology was applied in order to evaluate effects of milling parameters and to optimize grinding conditions for various responses. As independent variables roll gap (0.04–0.1 mm), differential (1.1.–1.9), roll speed (300–500 rpm) and feed rate (0.2–0.4 kg/cm min) were employed. Responsive variables were flour yield, ash content and energy consumption. In order to optimize milling process adequate models were obtained by regression analysis. Possibilities of the optimization of the milling parameters in order to obtain different combination of the desired outputs are illustrated by four examples.