Bioavailability of iron and zinc from tef in rats.

Abstract

Bioavailability of iron from tef (Eragrostis tef) was studied using anaemic rats by haemoglobin regeneration efficiency and apparent iron absorption. The bioavailability of zinc in tef prepared in the form of kitta and injera was evaluated with a rat bioassay, using the slope-ratio method and log10 total femur zinc or weight gain versus added zinc to the diets as response parameters. Diets were formulated by mixing kitta or injera prepared from tef with a semi-synthetic iron or zinc-free basal diet. Mean haemoglobin iron gain was lower in the groups fed kitta compared with injera fed groups. The respective mean haemoglobin regeneration efficiency and apparent iron absorption were 27.84% and 25.34% for anaemic rats when the kitta diet was fed and 76.85% and 79.40% when the injera diet was fed. For weight gain, slope-ratios relative to ZnSO4 were 37.1% for kitta and 77.4% for injera. For log10 total femur zinc, slope-ratios relative to ZnSO4 were 30.2% for kitta and 69.8% for injera. The phytic acid and phytate:zinc molar ratio of injera were 72% lower than that of kitta. The relative biological value (RBV) of iron and zinc in kitta was lowest compared to that of injera. The study suggested that natural lactic acid fermentation increased the RBV of iron and zinc.