A process is disclosed for preparing fluidizable particles of a biomass/catalyst composite material. The process comprises the steps of (i) providing a particulate, solid biomass material; (ii) forming a composite of the biomass material and a catalytic material; (iii) subjecting the biomass material to a thermal treatment at a torrefaction temperature at or above 200° C., and low enough to avoid significant conversion of the biomass material to liquid conversion products; and (iv) forming fluidizable particles from the biomass material. Step (ii) may be carried out before or after step (iii).