Effect of fermentation on nutrient composition, antinutrients, and mineral bioaccessibility of finger millet based Injera: A traditional Ethiopian food

Finger millet, like other cereals, contains high amounts of antinutrients that bind minerals, making them unavailable for absorption. This study explores the effect of traditional fermentation on nutritional, antinutritional, and subsequent mineral bioaccessibility (specifically iron, zinc, and calcium) of finger millet based Injera. Samples of fermented dough and Injera prepared from light brown and white finger millet varieties were analyzed for nutritional composition, antinutritional content, and mineral bioaccessibility following standard procedures. With some exceptions, the proximate composition of fermented dough was significantly affected by fermentation time. Compared to unfermented flour, the phytate and condensed tannin content significantly (p < 0.05) decreased for fermented dough and Injera samples. A strong decline in phytate and condensed tannin content was observed in white finger millet Injera as fermentation time increased, compared to light brown finger millet based Injera. The mineral bioaccessibility of Injera prepared from finger millet and maize composite flour increased with fermentation time, leading to a significant increase in bioaccessible iron, zinc, and calcium, ranging from 15.4-40.0 %, 26.8–50.8 %, and 60.9–88.5 %, respectively. The results suggest that traditional fermentation can be an effective method to reduce phytate and condensed tannin content, simultaneously increasing the bioaccessibility of minerals in the preparation of finger millet based Injera.