Yes, OBJToolkit does support materials with textures.
But don't forget that materials definitions aren't a part of .obj file and stored in .mtl file. Obj file has references to those .mtl file(s) (lines with mtllib token, as mtllib filename.mtl) to take materials definitions from. Materials definitions in .mtl files refer jpg/bmp/... files, so if you have images of .obj file but there isn't any corresponding .mtl file, materials (and textures) won't be imported.