Phenolic compounds were extracted from seeds of 22 cultivars of faba bean (Vicia faba L.) by using 80% (v/v) aqueous acetone. The total phenolic compound and condensed tannins contents of the extracts and their antioxidant activity were determined using the Folin-Ciocalteu’s phenol reagent, vanillin/HCl method, and ABTS and FRAP assays, respectively. The content of total phenolic compounds ranged from 40.7 to 66.1 mg/g extract and from 326 to 574 mg/100 g seeds. Contents of condensed tannins ranged from 2.40 to 49.9 mg/g extract and from 22.2 (FAB) to 365 mg/100 seeds. The extracts and seeds were characterized by Trolox equivalent antioxidant capacity (TEAC) values ranging from 0.550 (FAB 443) to 1.030 mmol Trolox/g extract (FAB 187) and from 4.85 (FAB 318) to 9.81 mmol Trolox/100 g seeds (FAB 187). Ferric-reducing antioxidant power (FRAP) values varied from 0.595 (FAB 443) to 0.908 mmol Fe2+/g extract (FAB 5023) and from 4.61 (FAB 297) to 7.90 mmol Fe2+/100 g seeds (FAB 187). The total phenolic content of faba bean extract was correlated with the results of the ABTS (r = 0.864) and FRAP (r = 0.862) assays. The coefficients of correlations between the contents of condensed tannins and ABTS and FRAP results were 0.543 and 0.862. We also noted a correlation between results of ABTS and FRAP assays (r = 0.795).
Part of the book: Plant Extracts