Abstract
Seed coat color is an important factor of quality in azuki bean, because consumers prefer grains with a good appearance as well as good taste. In this study, we investigated the seed coat color of azuki bean cv. Erimoshouzu by using an XYZ color system that is able to analyze color by three attributes; hue, lightness and chroma. Considerable variation was observed in seed coat color among seeds in different ripening stages. Dominant wavelength of hue ranged from 539.8 nm in immature seeds to 616.0 nm in mature seeds. When the color became deeper in fully ripened seeds, the Y value of lightness decreased from 17.01 to 8.92, and excitation purity of chroma from 41.1 to 19.8%. Although the variations were also expressed by the L*a*b* color system, XYZ color system was considered to be useful for analyzing seed coat color of azuki bean, since it measures color based on dominant wavelength.
