Comparison of color, anti-nutritional factors, minerals, phenolic profile and protein digestibility between hard-to-cook and easy-to-cook grains from different kidney bean (Phaseolus vulgaris) accessions.

The present study was aimed to evaluate the differences among anti-nutritional factors in relation to mineral absorption and protein digestibility of Easy-to-cook (ETC) and Hard-to-cook (HTC) grains from different kidney bean (KB) accessions.HTC grains showed lower a* (redness to yellowness) and b* (greenness to blueness) values and L* value than ETC grains. HTC grains had significantly higher Ca and Zn and lower Cu, Mn and Fe than ETC grains. ETC and HTC grains showed significant variation in mineral, total phenolic content (TPC), tannin and phytic acid content. TPC and tannin content were significantly higher for HTC grains, on the contrary phytic acid content was lower than counterpart ETC grains. Protein and in vitro protein digestibility (IVPD) also varied significantly between HTC and ETC grains and was found to be lower for HTC grains. Majority of phenolic compounds (PCs) were present in bound state in both ETC and HTC grains. Moreover, HTC grains showed higher amount of chlorogenic acid and catechin content than ETC grains in bound form. ETC and HTC grains from dark color accessions showed higher catechin content.