Total phenolics, flavonoids, tannins and antioxidant activity of lima beans conserved in a Brazilian Genebank

The objective of this study was to characterize for the first time polyphenols and DPPH (2-diphenyl-1-picryhydrazyl radical) antioxidant activity in commonly cultivated accessions of Phaseolus lunatus from an ex situ germplasm collection maintained by Embrapa, in Brazil. Furthermore, the study aimed to detect changes in total polyphenols, total flavonoids and condensed tannin for the same accessions after regeneration in a greenhouse. The results showed the diversity of the lima bean collection for phenolic compounds, which were strongly correlated with antioxidant activity. Lima beans accessions with the highest polyphenols and antioxidant activity were those with colored seeds. Conservation through cold storage of P. lunatus seeds in a cold chamber in the germplasm collection did not necessarily affect phenolic compounds. Variations observed in values after regeneration seeds may be mainly results of biotic and abiotic factors, including not only cultivar, but also environmental conditions. This study suggests that polyphenols in the lima beans present antioxidant activity, with possible beneficial effects for human health. It was expected that the potential of this tasty legume can be also used as a functional food crop and/or as a new ingredient in gastronomy.