Antioxidant Potentials of Different Genotypes of Cowpea (Vigna unguiculata L. Walp.) Cultivated in Bulgaria, Southern Europe

Abstract

Recently, there has been a growing interest in protein-rich foods and functional foods, as well as plants characterized by high levels of drought resistance. Vigna unguiculata L. Walp. from the Fabaceae family, also known as cowpea, was chosen as the subject of the present study. The antioxidant potentials of 15 genotypes cultivated in Bulgaria, Southern Europe, were determined. The research focused on the green mass used as feed and on the seeds used as an “ancient” traditional crop. The total phenolic content (TPC), total flavonoid content (TFC), radical scavenging capacity, determined via the DPPH method, and crude protein content were measured. The seed coat extracts showed higher contents of phenolics (291.0 ± 4.6 mgGAE/g) and flavonoids (83.5 ± 1.1 mgCE/g) and a stronger radical scavenging capacity (50.4 ± 0.7 µmolTE/g) than those obtained from the leaves (22.0 ± 0.5 mgGAE/g, 13.7 ± 0.5 mgCE/g, and 19.7 ± 0.6 µmolTE/g, respectively). The protein content in the seeds ranged from 20.5% to 27.0%. According to the obtained results, the cowpea genotypes with dark-colored seed coats showed greater antioxidant potentials but lower protein contents. Due to its high antioxidant content, strong radical scavenging capacity, and high protein content, V. unguiculata L. shows great potential as a functional food for humans and animals.