Mesostructured TiO2 nanomaterials with tuned crystallite sizes were elaborated by a novel green route using soluble starch as the structuring agent and titanium(IV) isopropoxide as the inorganic precursor. Using hydrothermal treatment (HT), soluble-starch removal from the inorganic matrix is about 80 wt % against 60 wt % for the enzymatic one (ET). Coupling the ET and HT leads upto 90 wt % of starch removal. The TiO2 crystallite sizes are stabilized at 6 nm.