Influence of nitrogen fertilizer rate and variety on tef [Eragrostis tef (Zucc.) Trotter] nutritional composition and sensory quality of a staple bread (Injera)

Abstract

In Ethiopia, tef is one of the major staple crops used as a basic raw material for food development such as stable bread called injera. Studies reported that imbalanced N fertilizer reduces the overall deliciousness of grains. Nowadays nitrogenous fertilizers are considered as the source of variation for the quality of injera, Ethiopian traditional flat bread. Therefore, a field experiment was conducted to assess the effects of N fertilizer rates (0, 30, 60, 90, and 120 kg N ha-1) on grain nutrition and sensory quality of injera of three tef varieties of (Kora, Boset, and Asgori). The experiment was conducted in main cropping season in Randomized Complete Block Design with three replications and Di-ammonium Phosphate was used in the same dose. Crop attribute parameters were determined using standard methods. Sensory quality and color of injera were determined by panelists and injera eye software respectively. Results showed that only protein content increased with nitrogen rates, while carbohydrate decreased significantly at (P < 0.05). Kora at the control plot (K0) had better color, flavor, texture, and taste values of injera, but they decreased with nitrogen rates. Injera from white tef varieties had a better acceptance as compared with Asgori red tef variety. Injera eye software indicated that the color of injera was significantly affected by varieties. Kora had a higher (55.74) lightness value followed by Boset (54.71), and Asgori (51.26). Injera from the Asgori variety had a maximum red color. Kora and Boset had higher yellow color on the control plot, but for Asgori it increased with the nitrogen rate.