Antioxidant capacity and nutraceutical compounds content of six common bean (Phaseolus vulgaris L.) varieties harvested in Morelos, Mexico

Common bean is considered one of the most important legumes in the world. It is the main source of protein, calories, B vitamins, minerals, polyphenols and other elements, which collectively give it a high nutraceutical value. In Mexico a great agrobiodiversity exists in the production of this grain, which implies the need to generate information regarding its nutritional quality as a tool to apply future genetic improvement programs. The purpose of this study was to characterize the antioxidant capacity (AC) and nutraceutical content of six bean varieties produced in Morelos State, Mexico.  Grain morphometric characteristics, color (L, a*, b* chroma and °hue), nutritional quality, AC (DPPH), nutraceutical compounds content, micro and macro nutrients were determined. A significant effect (p < 0.05) of variety on almost all the variables evaluated except for phytic acid, P, K, Ca, C, S and H was observed. Lower lightness was obtained in varieties with darker colors such as ‘Negro’/102 (24.96), ‘Negro’/104 (26.85) and ‘Sangre de Toro’ (32.41) and higher lightness in lighter colored varieties such as ‘Peruano’ bean (69.21), ‘Pinto’ (65.94) and ‘Flor de Mayo’ (50.14). Nutritional and nutraceutical quality of the latter genotype stood out, as it had the highest crude fiber content (5.71 %), total phenols (4.24 mg GAE g-1), flavonoids (1.99 mg CE g-1), AC (96.76% Inhibition), and a high protein content (23.29%). Results also exhibited significant correlation (p < 0.05) between total phenols and flavonoids with AC. It is concluded that the nutritional characterization carried out on bean varieties from important producing areas in Mexico provide a valuable database for genotype selection with high functional and nutritional character, either to be grown for direct consumption, future biofortification or breeding programs.