Genotypic variation for phenolic compounds in developing and whole seeds, and storage conditions influence visual seed quality of yellow dry bean genotypes

Seed coat colour is an important determinant of visual quality of dry bean as seeds are sold as dry commodity. Phenolic compounds have a major effect on colour of bean seeds. The objectives of the study were to determine the changes in phenolic compounds during seed development and in whole seeds of yellow bean genotypes with contrasting seed coat colour, and the effects of storage temperature and duration on seed phenolics and colour. Condensed tannin, phenolic acid, flavonoids and antioxidant activity were observed as early as 10 days after flowering in the developing seeds of Arikara Yellow, which darken at harvest and during postharvest storage. In contrast, CDC Sol and AAC Y073 seeds of which remain yellow, phenolic compounds and antioxidant activity were consistently low. Seed brightness (L*) and yellow colour (b*) were negatively correlated with phenolic compounds and antioxidant activity, and conversely, seed redness (a*) was positively correlated with phenolic compounds confirming a negative influence of phenolic compounds on seed coat colour. Yellow bean genotypes had low anthocyanin, but were high in β-carotene. Storage temperature influenced condensed tannin, and seed coat colour, whereas the duration of storage influenced phenolic compounds, antioxidant activity and seed coat colour. Higher temperatures (20 or 30 C) and longer storage duration (120 or 180 days) generally resulted in darker seeds with increasing redness compared to seeds stored at 6 C or for 60 days. AAC Y073 and CDC Sol with improved seed coat colour may increase consumer preference, value and marketability of yellow bean.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author