Ok I did a quick comparison. Ultra-Tex 3 (UT-3) is a modified tapioca starch, it's on the left in the pic. UT-3 is whiter in appearance, Natrasorb is cream color. When I rubbed a little between my fingers, UT-3 felt a little grainier, Natrasorb was very smooth.
They both absorb FO the same...