A steady state mathematical model for cocurrent spray drying was used to find the optimal spray drying process for sugar-rich foods. Maltodextrin-sucrose solution was used as a sugar-rich food model. The optimization of the spray drying process was carried out by finding a set of inlet variables to minimize the between the outlet air temperature and the glass transition temperature of the final products. The minimization was simplified by approaching the outlet drying air and average powder moisture content with the polynomial equations of the inlet variables in a range of interest. The drying condition at the lowest between outlet air temperature and product glass transition temperature provided the highest powder recovery at the cyclone obtained from experiment. This result shows that the stickiness of a particular sugar-rich food in spray drying can be minimized by choosing proper inlet variables using the glass transition temperature concept. (c) 2004 Elsevier Ltd. All rights reserved.