ANTHOCYANINS, POLYPHENOLS, FLAVONOIDS AND ANTIOXIDANT ACTIVITY IN COMMON BEAN (PHASEOLUS VULGARIS L.) LANDRACES
The aim of this work is to assess and describe a collection of Mexican populations of common bean (Phaseolus vulgaris L.), based on its content of monomeric anthocyanins, polyphenols, flavonoids, antioxidant activity, and grain physical characteristics. A collect of 25 bean populations was made at five states and regions in Mexico. They were cultivated in Santa Cruz Xoxocotlan, Mexico using a randomized complete blocks design with four replications. From a sample of a grain per population, polyphenols and flavonoids content were evaluated using UV-vis spectroscopy; anthocyanins content by differential pH; antioxidant activity using DPPH method, and a morphologic description of the grain was carried out. Variance analysis determined significant differences (P < 0.01) within and among population groups over all evaluated variables. Populations from Oaxaca and Puebla presented high content in anthocyanins, 1.6 and 2.1 mg C3GE/g, respectively. Polyphenols concentration was higher in seed coat (27.7 a 127.0 mg GAE/g) than in whole grain (1.3 to 5.4 mg GAE/g). Similar patterns were evaluated in flavonoids, from 5.9 to 21.5 in seed coat and 0.10 to 0.78 CE/g in grain, and in antioxidant activity (AA) from 132.5 to 1021.7 μmol ETrolox/g in seed coat. AA was significantly correlated with anthocyanins and polyphenols content. The group of outstanding populations in the evaluated compounds were: OAX-011-29, OAX-011-30, PUE-011-15, PUE-011-34, EM-01-01 and GRO-10-87. From these results we can infer that bean consumed by rural families from the central-south region of Mexico has high contents in anthocyanins, polyphenols and flavonoids with high antioxidant activity.