Polyphenols of Mung Bean (Phaseolus aureus L.) Cultivars Differing in Seed Coat Color: Effect of Dehulling

Abstract

Polyphenols are bioactive compounds, mainly concentrated in seed coats, which play an important role in human nutrition. Ten samples of mung bean (Phaseolus aureus L.), including three yellow cultivars representing a broad range of varietal characteristics, such as color and seed weight, were analyzed for their polyphenol content. The effect of dehulling on the polyphenol content was studied. The concentration of total polyphenols was found to be in the range of 280 mg to 356 mg/100 g whole seeds, 702 mg to 1296 mg/100 g seed coat, and 172 mg to 286 mg/100 g cotyledons. Most of the polyphenols were concentrated in the seed coat. The average polyphenol content of yellow cultivars was found to be higher than the green cultivars, except in ‘China Mung’. The acidic methanol extract polyphenols constitute about 75% and methanolic extract polyphenols about 25% of the total polyphenols. Dehulling reduced polyphenol content significantly (p < .01) by 14% to 52%. Yellow cultivars contained more seed coat polyphenols, which helps the seeds in combating against pathogens and seed viability.

Keywords:

• mung bean
• polyphenols
• dehulling

We are grateful to Agriculture Research Station, Aland Road, Gulbarga and farmer Gundajja for providing us mung bean samples. Thanks are also due to Gulbarga University, Gulbarga, for the laboratory facility.