Characterization of Soaking Process' Impact in Common Beans Phenolic Composition: Contribute from the Unexplored Portuguese Germplasm.

Elsa Mecha,Susana T Leitão,Bruna Carbas,Carla Brites,Maria R Bronze,Maria E Figueira,Pedro M Moreira,Maria Manuela Veloso,Ana T Serra,Ricardo Gomes,Maria C Vaz Patto

doi:10.3390/foods8080296

Abstract

Despite the common beans’ nutritional and phytochemical value, in Portugal its consumption decreased more than 50% in the last decade. The present study aimed to characterize phenolic composition of the Portuguese traditional varieties and corresponding soaked seed fractions (including soaking water). With such purpose, the phenolic composition (total content of soluble phenolics, flavonoids, and proanthocyanidins) and in vitro antioxidant activity were evaluated in the raw whole flour of 31 Portuguese common bean varieties. The phenolic composition of the soaked fractions was respectively compared to the raw flour. Phenolic compounds’ identification and relative quantification were achieved by UPLC-TripleTOF-MS for one representative variety and their fractions. The highest phenolic content was found in colored varieties and the brown market class highlighted as the richest one. The loss of phenolic compounds to the soaking water was highly dependent on variety. The predominant phenolic compounds’ classes were flavan-3-ols (soaking water and coats), flavonols (coats), and phenolic acids (cotyledons). This characterization study showed the diversity on the phenolic composition of Portuguese varieties and the need to adjust the soaking and peeling processes to the variety (considering the possible loss of potential health promoter compounds, e.g., phenolic compounds).

Highlights

Common bean (Phaseolus vulgaris L.) is one of the most widely grown grain legume species (Fabaceae family), cropped across a wide range of different environments from arid climates to humid tropics [1]
The results obtained in this study showed that the phenolic compounds’ content in the highly genetically diverse Portuguese common bean germplasm was quite variable
Such variability allowed for study of the impact of the traditional soaking process only with water, overnight, in different common bean varieties

Summary

Introduction

Common bean (Phaseolus vulgaris L.) is one of the most widely grown grain legume species (Fabaceae family), cropped across a wide range of different environments from arid climates to humid tropics [1]. Common beans nourish millions of people in developing and developed countries It fulfills 28% of the carbohydrates, 34% of the dietary fiber and 25% of the protein dietary recommended intake (DRIs) values for an average healthy adult (18–65 years old) [2,3,4]. In Portugal, regardless of the national rich common bean germplasm [7], data from 2007 to 2017 reported a production decrease of 53%. This decrease is dramatic, considering that common bean represent 75% of the Portuguese grain legumes total consumption and the country is producing less than 10% of its intake, relying heavily on imports [8]. Part of the solution may involve the valorization of traditional varieties in both high and low-income communities

Methods

Results

Conclusion