Characterization and Metabolic Profile of Kidney Beans (Pharsalus vulgaris L.) With Varied Seed Coat Color.

The research assessed the physical and chemical traits, as well as the metabolomic diversity, of sixteen kidney bean (Phaseolus vulgaris L.) accessions exhibiting varying seed coat colors. Significant differences were noted in the color dimensions (L*, a*, b*). Antioxidant activity exhibited significant variation, with 2,2-diphenyl-1-picrylhydrazyl values ranging from 58 to 1179 and ABTS values from 476 to 2121 µmol TE/100 g. A strong positive correlation (r = 0.84) was observed between antioxidant activity and seed coat color. Polyphenolic profiling identified ten phenolic acids and flavonoids including gallic, chlorogenic, protocatechuic, p-coumaric, cinnamic, t-ferulic, and sinapic acids, and rutin, quercetin and kaempferol (418-1125 mg/kg), with darker genotypes enriched in rutin, quercetin, kaempferol, and trans-ferulic acid. The amino acid profile showed a well-balanced composition of essential amino acids, with markedly high levels of lysine and leucine. GC-MS analysis identified 80 metabolites, with dark-colored accessions revealed a strong association with sugars, organic acids, amino acids, and phenolic compounds. In contrast, lighter-colored accessions were predominantly linked with fatty acids and hydrocarbons. FTIR analysis revealed similar functional group profiles among the accessions; however, variations in peak intensities were genotype-dependent. Furthermore, seed coat color showed a strong effect on the metabolic composition and antioxidant potential.