Buckwheat seeds are an important pseudocereal used as flour in baking industry. Also hulls, a waste material produced in the de-hulling process is of certain interest. Hemicelluloses were isolated from buckwheat hulls. They were characterised and shown to be of the glucuronoxylan type. Their effect upon rheological properties of gels of com starch with varying amount of hemicelluloses (0.3%; 0.5%; 0.7% and 1.0%) is described. The rheological properties of the blends were investigated using the Brabender viscograph and Rheotest 2 viscograph. At the same pasting temperature, pastes containing an optimum of hemicelluloses (0.5-0.7%), exhibited the highest viscosity and stability against mechanical stress. At this optimum concentration, hemicelluloses increased substantially the apparent viscosity of the pastes at low and high shear rates and this trend was observed also with increase in temperature. Effect of the hemicellulose addition to com starch on retrogradation of the pastes was studied in the refrigeration as well freeze-thaw processes. A minimum addition of hemicelluloses (0.3%) significantly affected the syneresis of starch.