Structural Analysis and Measurement of Anthocyanins from Colored Seed Coats of<i>Vigna, Phaseolus</i>, and<i>Glycine</i>Legumes

Abstract

Herein the structures and peel contents of anthocyanins from 26 kinds of 11 species of edible legumes are reported. In the scarlet bean (Phaseolus coccineus) delphinidin 3-glucoside was found, and in the sultanipya bean (Phaseolus lunatus) peonidin 3-glucoside and peonidin 3-rutinoside. In the black turtle bean (Phaseolus vulgaris) delphinidin 3-glucoside, petunin, petunidin 3-glucoside, malvin, and malvidin 3-glucoside were assayed. We also succeeded in the isolation and structural analysis of an anthocyanin from the adzuki bean (Vigna angularis) as a cyanin for the first time. The anthocyanin contents of black colored seed coats were very high at around 0.2% for peel, and these beans may therefore be expected to find applications as food colorants. In individual Vigna species from different districts, consistency in the variety of anthocyanins was observed.