Pericarp of colored-seeded common bean (Phaseolus vulgaris L.) varieties a potential source of polyphenolic compounds
University of Life Sciences in Lublin, Faculty of Horticulture and Landscape Architecture, Department of Vegetable Crops and Medicinal Plants, Akademicka 15, PL20-950 Lublin, Poland
Bioactive substances produced by plants are defined as secondary metabolites causing different pharmacological effects in human organism. Various plant raw materials, some known as vegetables or spices, are their source. Pericarp of white-seeded common bean varieties is a pharmacopoeial product traditionally used as an antidiabetic agent. The object of this study was to evaluate the biological value of pericarp of colored beans (cultivars: ‘Małopolanka’, ‘Nida’, ‘Rawela’, ‘Tip Top’, and ‘Nigeria’) compared to the reference white-seeded cultivar (‘Laponia’). Bean pericarp was characterized by a high level of polyphenolic compounds and antioxidant activity. Its phenolic acid content (expressed as caffeic acid equivalents) was at a similar level, at least 0.1 mg g-1 (0.01%). The highest amount of flavonoids was accumulated by the cultivars with dark blue and black seeds, respectively 0.138 and 0.139 mg g-1 DW, as well as by the white-seeded cultivar (0.132 mg g-1 DW). The highest antioxidant activity (AA) was found for bean extracts of the cultivars ‘Laponia’ and ‘Małopolanka’, respectively 12.35 and 12.10%. Phenolic acid content was significantly positively correlated with AA of the bean extracts tested. This study indicates that pericarp of the colored-seeded bean cultivars is characterized by high biological value and can be used as a source of polyphenolic compounds.