Evaluation of physicochemical, textural, mineral and protein characteristics of kidney bean grown at Himalayan region

Different kidney bean lines (48) were evaluated for diversity in seed (physicochemical, hydration, textural and cooking) and flour (antioxidant, total phenols, minerals, protein and pasting) properties. All the lines showed significant differential accumulation of minerals i.e. Fe, Mn, Cu, Na, Zn, K, Mg and Ca. Mn content was correlated with L* and b* values while Ca and Mg contents were correlated antioxidant potential relative to the phenolic content. Antioxidant activity (AOA) was measured using 2,2-diphenylpicrylhydrazine (DPPH) antioxidant assay and total phenolic content (TPC) was measured using Folin–Ciocalteu assay. AOA and TPC ranged from 2.14 to 94.24% of DPPH inhibition and 0.07 to 7.10 mg GAE/g, respectively. Light grain lines with lower L* had lower AOA and TPC as compared to the darker grain lines with higher L*. SDS-PAGE analysis showed the presence of 26 major polypeptides ranged from 12 to 137 kDa and among them, eight polypeptides were subjected to MALDI-TOF/MS analysis. These polypeptides were identified as phaseolin (alpha-type precursor) of 200 kDa, legumin (Phaseolus vulgaris) of 86 kDa, methionine synthase (Glycine max) of 84 kDa, 5-methyltetrahydropteroyltriglutamate-homocysteineS-methyltransferase, putative (Ricinus communis) of 80 kDa, chain A purple acid phosphatase of 59 kDa, IAA-protein conjugate (P. vulgaris) of 39 kDa and lectin (P. vulgaris) of 36 kDa. It has been observed that most of the lines which show the presence of 59 kDa protein also showed the presence of high activity of antioxidant.