Pericarp of colored-seeded common bean (Phaseolus vulgaris L.) varieties a potential source of polyphenolic compounds

R. Nurzyńska-Wierdak, H. Łabuda, H. Buczkowska* and A. Sałata

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
*Correspondence: halina.buczkowska@up.lublin.pl

Abstract:

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.

Key words:

Total phenolic content and antioxidant activity of tritordeum wheat and barley

M. Eliášová* and L. Paznocht

Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcka 129, CZ16521, Prague 6, Czech Republic
*Correspondence: eliasovam@af.czu.cz

Abstract:

Whole grains are a source of numerous antioxidant compounds such as phenolic compounds, anthocyanins, phenolic acids, proanthocyanidins, lignans and others which are able to scavenge free radicals. Thus cereals seem to be very useful in preventing chronic diseases like metabolic syndrome (obesity, high blood pressure, high blood triglyceride and glucose levels), diabetes, neurodegenerative diseases, cancer and chronic inflammatory diseases. Recently, there has been an increased consumer demand for cereal based foods, especially whole cereals. Such demand provides scope for innovations of which an important one is introduction of a completely new cereal cross called tritordeum. This alternative cereal, which is presented as a good source of health beneficial compounds, was assessed in this study and compared with wheat and barley. The total phenolic content (TPC) and related total antioxidant activity (TAA) were investigated via two spectrophotometric methods using a stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH) and Folin-Ciocalteau reagent respectively. Both TPC and related TAA values of tritordeum and wheat were similar but were significantly lower compared to barley. Results have also revealed a close relationship between TAA and TPC (R2 = 0.93, p < 0.05), which might suggest that increased antioxidant activity in those grains is caused by phenolic compounds contained in them. Tritordeum seems to represent a new cereal with good prospects; nevertheless more detailed analysis of its health related compounds is required.

Key words:

cereals, DPPH, spectrophotometry, total antioxidant activity, total phenolic content, tritordeum