Abstract: In the study a significant linear correlation is shown between x and y chromaticity coordinates of the color of buckwheat groats in CIE xyY diagram and the regression function y = f (x) is given. A quantitative correlation is established between the change in color and the content of the main components of buckwheat groats biochemical complex (starch and proteins) and dextrin which occurs during hydrothermal processing of buckwheat grain. The results obtained allow assessing the quality of buckwheat groats by its color as well as open up the possibility of effective management of the groats production processes. The range of colors is determined in which the content of the studied components of buckwheat groats biochemical complex changes insignificantly, so, it may be used as a basis for rational choice of modes of hydrothermal processing of buckwheat grain.