抄録
Colors of the various seed coats of beans range from white to black, brown, green, red, purple, orange, and yellow. The pigments responsible for these seed coat colors include condensed tannins for brown color, chlorophyll for green, red through purple and black colors for anthocyanins, and orange to yellow for carotenoids. Among these diverse legumes, seed coat pigments of edible legumes have recently been attracting attention not only for their coloration when cooked, but also for their biological function in lifestyle-related diseases. There are many edible legumes with red, purple, and black colors in the seed coat, including soybeans, common beans, and adzuki beans. Most of the colors produced by polyphenolic pigments come from anthocyanins, which have a simpler structure than what is found in flower petals. However, our recent study revealed that the major seed coat-pigments of red azuki beans are not anthocyanins, but catechinopyranocyanidins which have a condensed structure of catechin and cyanidin without any sugars. This paper introduces the structure and content of anthocyanin pigments in the colored seed coat of the genera Glycine, Phaseolus, and Vigna. In addition, this paper presents the structure and content of non-anthocyanin pigments, catechinopyranocyanidins, which are responsible for the purple color of an-paste, and a new biosynthetic intermediate of anthocyanin found in the seed coat of immature black soybeans.
