MEASURING DESIRABLE AND UNDESIRABLE COLOR IN WHITE AND YELLOW FOOD CORN

Subjective field and objective nondestructive laboratory measurements of color in white and yellow corn were compared. L, a, b, and E color values were correlated to subjective field color grades by a trained o bserver. Physical factors that affect the variability of L, a, b and E color values such as position of the germ and adhering colored cob ma terial were examined. Variability of objective measurements decreased when colored cob material was removed or the kernels were positioned w ith the germ facing away from the light source during color measuremen ts. Pearson correlation coefficients between field color grades and L, a, b, and E color values were <0.54. Differences in endosperm hardnes s, pericarp thickness, and pericarp gloss between cultivars with the s ame subjective field ratings contributed to the low correlation values . The L, a, b, and E color values provide a general index of color esp ecially for yellow corn. Important subtle differences in color, partic ularly in white corn, were not accurately determined by these indices. Subjective evaluation of corn on the cob viewed in the field is the m ost effective method for selecting appropriate color corn.