Aromatization of texturized soy protein (TSP) may be a way to make a more attractive product from a sensory viewpoint. An alternative is to use aroma precursors as a pre-extrusion flavoring method, avoiding an increase of lipid content in the final product. The addition of thiamine to the soy protein concentrate (SPC) and effects of the extrusion conditions on the physical, functional and sensory characteristics of TSP were investigated. SPC with 1.5% thiamine added was extruded in a single screw extruder, and Response Surface Methodology for two independent variables was used: moisture content (MC) of SPC (from 28.4 to 39.6% dry basis) and screw speed (from 190 to 242 rpm). A sample of SPC without thiamine was extruded under the same conditions as the center point of the design. Expansion ratio, density, cutting force, protein solubility, emulsion stability, meat aroma intensity and aroma acceptance (just-about-right and nine-point-hedonic scales) of TSP were evaluated. The results were also subjected to principal component analysis (PCA). A reduction of MC increased the expansion ratio, and reduced density and ideal meat aroma intensity of the extrudates. However, the highest meat aroma intensity was noted when the MC was around the central point. Reduction of screw speed increased the cutting force of the extrudates. Neither independent variable had an effect on the functional characteristics of the extrudates. PCA showed that the TSP obtained under intermediate MC, unlike the TSP without added thiamine, had high expansion ratio and cutting force and low density, as well as high meat aroma intensity and aroma acceptance on both sensory scales. Also, the TSP from the highest MC was characterized by lower protein solubility in comparison to the TSP from the lowest MC. Concluding, SPC with added thiamine resulted in TSP with adequate physical and functional characteristics, and with meat aroma.