In this study, white cheese powder was produced using a pilot scale spray drier and response surface methodology was used to optimize the operating conditions of spray drying. The independent variables were inlet drying temperature, atomization pressure and outlet drying temperature, while drying experiments were carried out with an inlet drying air temperature range of 160-230 degrees C, an outlet drying air temperature range of 60-100 degrees C and an atomization pressure range of 294-588 kPa. The responses were nonenzymatic browning index, free fat content, solubility index, bulk density of cheese powder and exergy efficiency of the spray drying process. Optimum operating conditions were found to be an inlet drying temperature of 174 degrees C, atomization pressure of 354 kPa, and an outlet drying temperature of 68 degrees C. At this optimum condition, nonenzymatic browning index, free fat content, solubility index, bulk density and exergy efficiency were found to be 0.123 OD/g dm, 40.7%, 82.7%, 252 kg/m(3) and 4.81%, respectively. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.