The physical and functional properties viz. moisture content, bulk density, browning index, protein digestibility, hardness, water and oil absorption capacity were studied during pilot scale roasting of soybean at different roasting times from 10 to 35 min and roasting temperatures from 160 to 190 °C and its interaction applied. The changes in physical and functional properties were recorded as dependent variables data which were fitted to linear and quadratic models. Roasting of soybean at 186 °C for 30 min (optimized conditions) gives the optimum range of moisture content (2.90–3.20%), hardness (70–75 kg), browning index (62–68), bulk density (0.66–0.68 g/cc), protein digestibility (80–82%) and a water/oil absorption capacity (1.50/1.22 g/g) with 0.68 desirability. The granular morphology and DSC results were significantly changed after roasting. The optimized pilot scale roasting study of soybean will help to scale-up the small-scale industries for the commercial production of better quality of food products.