The objective of the current research project was to optimize the parameters:drying air temperature (T in ℃) and dry residue re-circulation rate (RR in %) by Response Surface Methodology (RSM),in the drying of a residue in a pneumatic flash dryer,evaluating the quality of the dried residue.The raw material used in the present research was the residue from soybean protein extracts (soymilk),called "okara",which was provided by an industry that uses a Japanese soybean cultivar cultivated in Brazil.