Structural Analysis and Measurement of Anthocyanins from Colored Seed Coats of Vigna, Phaseolus, and Glycine 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 therefor be expected to find applications as food colorants. In individual vigna species from different districts, consistency in the variety of anthocyanins was observed.