Nutritional ranking of 30 Brazilian genotypes of cowpeas including determination of antioxidant capacity and vitamins

A B S T R A C T This study aimed to establish a nutritional ranking of 30 genotypes of cowpea (Vigna unguiculata L. Walp). The results showed the proximate composition varies among genotypes in protein (20–30%) and dietary fiber contents (20–35%), in protease inhibitors (2–4 UI/mg protein), lectin (40,000–640,000 UH/kg meal) and essential amino acid levels, in vitro protein digestibility (30–40%) and in the apparent concentration of expressed proteins. The antioxidant capacity varied from EC50 of 9.54–38.7 mg seed extract/mL DPPH and the highest values detected for alpha- and delta-tocopherol were 0.38 mg/g and 1.88 mg/g, respectively. The analysis of a nutritional quality index based on the weighted average content of total protein, dietary fiber, iron, zinc, protease inhibitors and lectins allowed ranking genotypes. In descending order the 5 best genotypes were: BRS-Cauame ´ > BRS-Tumucumaque > Canapuzinho > BRS-Potengi > BRS-Urubuquara.