Grain mineral nutrient profiling and iron bioavailability of an ancient crop tef (Eragrostis tef)

Tef (Eragrostis tef) is an underutilized food crop rich in minerals, vitamins, and amino acids. However, mineral profiling of diverse tef accessions, and estimation of bioavailable iron from tef has been lacking. In this study, we analyzed the mineral content of 41 tef accessions along with major cereals. Our analysis revealed that tef seeds contain significantly more minerals than maize, rice, and the wheat varieties used in this study. A significant variation in mineral content was also observed across the tef accessions. We also performed a relative estimation of Fe bioavailability from selected tef accessions and reference crops using an established Caco-2 cell bioassay. This bioassay measures human intestinal cell Fe uptake via intracellular ferritin formation, a storage protein that is a validated marker of Fe uptake. Higher levels of Fe uptake were observed in the PI-494307, PI-494425, and PI-195937 accessions, than those recorded in cells fed wheat, rice, or tef accessions PI-329681, PI-494408 and PI-494293. There was no marked difference in phytic acid (PA) content between tef and wheat, while the PA level in rice was lower than tef and wheat. Enhanced Fe uptake evident in tef accession PI494425 could not be explained by seed Fe content. The Fe content of PI-494425 was lower than the other tef accessions, suggesting that other factors control the amount of bioavailable Fe from tef. Considerable variation in mineral content and bioavailable Fe between tef and other cereals indicate a potential for improving mineral nutrition from this vital food crop