Common buckwheat (Fagopyrum esculentum Moench) flour is widely used in food products due to its desirable taste, textural structure and nutrients. The effect of water content varying from similar to 20% to similar to 80% on the thermal behaviors of common buckwheat flour and its isolated starch was investigated by differential scanning calorimetry (DSC) from 40.0 degrees C to 105.0 degrees C and from -60.0 degrees C to 160.0 degrees C. The gelatinization temperature of buckwheat flour was between 60 degrees C and 85 degrees C and it decreased while the water content increased. Isolated buckwheat starch showed a narrower gelatinization range from 60 degrees C to 75 degrees C. T(o), T(p) T(c) and Delta H of the ice melting peak of buckwheat flour and starch in the second scan increased as the water content increased. Their viscosity, crystallinity and retrogradation were also analyzed. (C) 2009 Elsevier Ltd. All rights reserved.