DIFFERENCES IN FYTOCHEMICALS CONTENT IN COLOURED CULTIVARS OF COMMON BEAN (PHASEOLUS VULGARIS L.)

Abstract

Nowadays, legume production is increasing as the world population but its consumption is declining due to dietary habit changes. Industry is finding new uses of legumes and creating new foods with a positive effect on health and well-being of humans. Key components in legume (like protein, soluble and insoluble fibre, resistant starch, and bioactive polyphenols) make beans suitable for a wide range of food product applications. The main phenolic compounds present in legume flours are flavonoids. The study is focused on determination of bioactive compounds content in seeds of four varieties of common bean. The samples of plant material were collected from the area of Piešťany (Slovakia). The samples of common bean seeds were homogenized and a methanolic extract was prepared. These extracts were used for analyses. The total content of polyphenols was determined spectrophotometrically and the content of individual phenolic by using the RP-HPLC/DAD method. The content of risky metals in samples was determined using the AAS method. TPC in studied varieties of common bean were determined in the range from 2156.87 mg.kg-1 (NEGRA) to 1362.70 mg. kg-1 (ZENIT). Highest concentration of phenolic acids was determined in ellagic acid, where the average value was 0.21845 mg.kg-1 DM (dry matter) and the lowest in trans- caffeic acid, with the average value 0.02380 mg.kg-1 DM. Highest concentration of flavonoids was determined in vitexin, where the average value was 0.02480 mg.kg-1 DM and the lowest in kaempferol, with the average value 0.00545 mg.kg-1 DM. Highest macro elements amount was determined in white beans. For potassium it was 12277 mg.kg-1 (ZENIT) and the lowest was in manganese, and it was 10.70 mg.kg-1 (RUBIN) in red beans. From the analyzed varieties we have found that they are important source of polyphenol substances with a demonstrable bioactive effect.