Optimization of process parameters for soaked soybean splits roasting using response surface methodology

Generally, roasting of any food grains or legumes are carried out to improve the palatability and to improve the special characteristics like physical texture, colour and etc.

This study was carried out to optimize the process parameter for soaked soybean splits in an open type LPG gas assisted soybean roaster using response surface methodology with process variables viz., soaking time and roasting time. The capacity of soybean roaster is 15 kg/batch, rotating drum speed with 24 rpm and power operated with a 0.5 hp electric motor. A central composite rotatable design (CCRD) was used to select variables level i.e. soaking time (60-180 min) and roasting time (4-10 min).

The effect of moisture content on some physical properties of soybean seed and split were determined. The results showed that the roasted soybean splits increased linearly in length, width, thickness, arithmetic mean diameter, geometric mean diameter, square mean diameter, equivalent diameter, unit volume and surface area, where in sphericity, aspect ratio and shape factor decreased linearly with the increase in moisture content of soybean splits. The process variable had a significant effect on Hunter color and textural properties. The optimized soaking time and roasting time in the developed roaster is 123.362 min and 7.702 min, respectively.