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:

DPPH, flavonoids, Phaseoli pericarpium, phenolic acids, tannins

Impact of the farming systems on the content of biologically active substances and the forms of nitrogen in the soils

T. Meysner¹, L. Szajdak¹ and J. Kuś²

¹Research Center for Agricultural and Forest Environment, Polish Academy of Sciences,Bukowska 19, 60-809 Poznań, Poland; e-mail: szajlech@man.poznan.pl
²Institute of Soil Science and Plant Cultivation, Czartoryskich 8, 24-100 Puławy, Poland;e-mail: jankus@iung.pulawy.pl

Abstract:

Investigations were carried out in 2000 and 2001 to assess the impact of four farming systems on the content of biologically active substances and different forms of nitrogen in the soils. The transformation of bound amino acids and the total amount of free phenolic acids, urease activity as well as the total nitrogen, concentration of ammonium, nitrate, organic carbon, and humus in the soils were related to the choice of the farming systems. The highest concentration of bound amino acids, lysine and β–alanine, the total nitrogen, organic carbon, and humus in soils was found in ecological and conventional systems. It was confirmed that the increase of free phenolic acids in the soils of continuous cropping of winter wheat was followed by the decrease of the yearly mean concentrations of urease activity, the total amount of bound amino acids, the total nitrogen and grain yields, weight of 1000 grains, and number of ears m-2. The conventional system affects the increase of the yearly mean concentrations of the total amount of bound amino acids, the ammonium ions, and the grain yield, weight of 1000 grains, number of ears m-2 and the decrease of the total amount of free phenolic acids in the soils.

Key words: