Polyphenols content and antioxidant capacity of thirteen faba bean (Vicia faba L.) genotypes cultivated in Tunisia

In vitro antioxidant capacity of thirteen genotypes of faba bean (Vicia faba L.) collected during three different growing stages (vegetative, reproductive and maturity) have been evaluated. For the vegetative stage (VS) and reproductive stage (RS) the whole plant (WP) has been used for the analysis while for the maturity stage (MS) the plant was divided and analyzed in different parts, the whole seed (WS), seed coat (SC), cotyledons (Cot) and pod (Pod). The antioxidant capacity has been evaluated by means of the total phenolic and total flavonoid contents (TPC and TFC respectively), the ferric-reducing/antioxidant power (FRAP) and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assays. The results showed different antioxidant properties for the same genotype when considering the different parts or stages of the plant. High content of both total phenolics (>92.85 mg as gallic acid equivalent (GAE)/g of dried plant) and flavonoids contents (>11.87 mg as rutin equivalent (RE)/g of dried plant) were found for all genotypes during the vegetative and the reproductive stages, which also showed the highest antioxidant activity (FRAP value >= 1.157 mmol/g and DPPH radical-scavenging capacity >43.49%), indicating their potential as natural sources of antioxidant foods. For the maturity stage, the highest values for the TPC,TFC, FRAP and DPPH scavenging capacity were observed for the pods and the lowest for the cotyledons. The results of this study indicate that faba beans are a good source of natural antioxidants independently to their genotype. The quantification of the antioxidant capacity according to the stage and the plant part could be suitable for applications on the food industry in relation to production and preservation of faba bean food products. (C) 2011 Elsevier Ltd. All rights reserved.