In a previous work, a theoretical model for the cationization of wheat starch in a modular self-wiping corotating twin screw extruder has been developed and experimentally validated. Our objective in the present article was to use this model in a first step to optimize the cationization reaction on a laboratory scale extruder, and, in a second step, to extrapolate the results to an industrial scale extruder. We will show that the use of a theoretical model of reactive extrusion allowed us to define screw profiles and processing conditions according to the end-use properties of the desired product and the limits of the process. Based on the performances obtained at laboratory scale, it permitted also to predict the performances of an industrial production line.