Edited by: Francesca Sparvoli, National Research Council, Italy
Reviewed by: Grama Nanjappa Dhanapal, University of Agricultural Sciences, India; Stefano Predieri, Institute of Biometeorology of the National Research Council, Italy
*Correspondence: Habteab M. Ghebrehiwot
This article was submitted to Crop Science and Horticulture, a section of the journal Frontiers in Plant Science
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Injera is a fermented, sour bread consumed as a staple food in Eritrea and Ethiopia. The bread can be prepared from various cereals but tef [
The challenges facing global food security due to increasing population, increasing pressure on finite land, and water resources and climate change calls for new and innovative solutions (Mabhaudhi et al.,
In the course of human history, an estimated 7000 plant species have been cultivated for consumption at some point (FAO,
While tef may be of major importance in Ethiopia and Eritrea where it is the major source of flour used for preparing injera, it remains underutilized outside of these countries. There is a dearth of information on the agronomy, eco-physiology and nutritional value of these wild
The objective of this study was therefore to: (i) assess the nutritive value of
Seeds (10 kg of grains) of
A1 | 250 | 0 | 0 | B1 | 250 | 0 | 0 |
A2 | 250 | 12.5 | 5 | B2 | 250 | 12.5 | 5 |
A3 | 250 | 25 | 10 | B3 | 250 | 25 | 10 |
Injera is made by mixing a cereal (e.g., tef, sorghum, barely, and blends thereof) flour with water to make a dough, and then triggering a fermentation process by inoculating the dough with
In this study, injera was prepared as described by Yetneberk et al. (
After fermentation, 10% of the fermented dough was thinned with 100 mL of water and cooked in 200 mL of boiling water for 1 min. The gelatinized batter was cooled to ≈45°C at room temperature and added back to the fermenting dough. About 200 g of the fermented batter was poured in a circular manner onto a 45-cm diameter hot clay griddle, covered, and baked for approximate 2 min. The baked injera was then removed and kept in an airtight container.
In order to determine consumer acceptability of injera prepared using
The determination of protein, fat and fiber was carried out using the Dumas method (dry combustion) on the Leco TruMac™ instrument (2010 LECO Corporation, Saint Joseph, Michigan, USA). This involved a total combustion of the matrix under oxygen. The gases produced were reduced by copper and then dried, while the CO2 was trapped. The nitrogen was then quantified using a universal detector. Mineral analysis was conducted using a Hunter apparatus (HCL extraction on the ICP), similar to that used for soil analysis.
Data on the chemical composition of tef and
The chemical composition of
Ash | g/100 g | 2.49 ± 0.03 | 3.18 ± 0.03 | |
Fat | g/100 g | 2.64 ± 0.02 | 2.83 ± 0.05 | |
ADF | g/100 g | 7.50 ± 0.64 | 18.34 ± 0.10 | |
NDF | g/100 g | 11.78 ± 0.57 | 24.30 ± 0.29 | |
Crude-protein | g/100 g | 8.28 ± 0.04 | 18.47 ± 0.05 | |
Ca | mg/100 g | 0.19 ± 0.04 | 0.22 ± 0.00 | |
Mg | mg/100 g | 354.18 ± 1.16 | 115.00 ± 0.63 | |
K | mg/100 g | 0.42 ± 0.06 | 0.584 ± 0.03 | |
Na % | mg/100 g | 0.01 ± 0.00 | 0.00 ± 0.00 | |
K/Ca+Mg | mg/100 g | 0.44 ± 0.02 | 0.48 ± 0.00 | |
P | mg/100 g | 0.42 ± 0.00 | 0.41 ± 0.05 | |
Zn | mg/100 g | 37.30 ± 0.81 | 51.43 ± 0.07 | |
Cu | mg/100 g | 4.27 ± 0.08 | 10.02 ± 0.14 | |
Mn | mg/100 g | 354.18 ± 1.17 | 114.94 ± 0.64 | |
Fe | mg/100 g | 50.78 ± 1.08 | 84.53 ± 0.93 |
The flour of
Sensory evaluation is defined as the examination of a product (e.g., foods and beverages) through the evaluation of the attributes traceable by one or more of the five human senses—taste, smell, touch, sight, and hearing (Piana et al.,
In the current study, a panel of 10 judges was used to describe the degree of consumer acceptance and satisfaction to the injera prepared using different combinations of
Injera varieties | A1 | A2 | A3 | B1 | B2 | B3 | |
pH | 3.8 | 4.1 | 4.0 | 3.9 | 3.8 | 3.8 | |
Dislike very much | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
Dislike moderately | 2 | 0 | 0 | 1 | 1 | 2 | 2 |
Neither like nor dislike | 3 | 1 | 1 | 2 | 2 | 1 | 1 |
Like moderately | 4 | 6 | 2 | 4 | 2 | 6 | 4 |
Like very much | 5 | 3 | 7 | 3 | 5 | 1 | 3 |
Total responses | 10 | 10 | 10 | 10 | 10 | 10 | |
Mean rating | 4.2 |
4.6 |
3.9 |
4.1 |
3.6 |
3.8 |
|
SE | 1.14 | 1.30 | 0.71 | 0.84 | 1.05 | 0.71 | |
% “Like” responses | 90 | 90 | 70 | 70 | 70 | 70 | |
Dislike very much | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
Dislike moderately | 2 | 0 | 0 | 0 | 0 | 1 | 0 |
Neither like nor dislike | 3 | 1 | 0 | 1 | 1 | 0 | 3 |
Like moderately | 4 | 4 | 1 | 6 | 4 | 8 | 5 |
Like very much | 5 | 5 | 9 | 3 | 5 | 1 | 2 |
Total responses | 10 | 10 | 10 | 10 | 10 | 10 | |
Mean rating | 4.4 |
4.9 |
4.2 |
4.4 |
3.9 |
3.9 |
|
SE | |||||||
% “Like” responses | 90 | 100 | 90 | 90 | 90 | 70 | |
Dislike very much | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
Dislike moderately | 2 | 0 | 0 | 0 | 0 | 1 | 0 |
Neither like nor dislike | 3 | 0 | 0 | 0 | 0 | 3 | 2 |
Like moderately | 4 | 6 | 1 | 4 | 2 | 5 | 3 |
Like very much | 5 | 4 | 9 | 6 | 8 | 1 | 5 |
Total responses | 10 | 10 | 10 | 10 | 10 | 10 | |
Mean rating | 4.4 |
5.0 |
4.8 |
4.8 |
3.8 |
4.1 |
|
SE | |||||||
% “Like” responses | 100 | 100 | 100 | 100 | 60 | 80 | |
Dislike very much | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
Dislike moderately | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
Neither like nor dislike | 3 | 0 | 0 | 0 | 0 | 2 | 0 |
Like moderately | 4 | 5 | 0 | 2 | 2 | 6 | 4 |
Like very much | 5 | 5 | 10 | 8 | 8 | 2 | 6 |
Total responses | 10 | 10 | 10 | 10 | 10 | 10 | |
Mean rating | 4.5 |
5.0 |
4.8 |
4.8 |
4.0 |
4.6 |
|
SE | |||||||
% “Like” responses | 100 | 100 | 100 | 100 | 80 | 100 |
1 | A1 and A2 | 19.00 |
25.00 ns | 20.00 |
25.00 ns |
2 | A1 and A3 | 49.5 ns | 45.00 ns | 30.00 ns | 35.00 ns |
3 | A1 and B1 | 40.5 ns | 34.00 ns | 30.00 ns | 35.00 ns |
4 | A1 and B2 | 37.00 ns | 36.00 ns | 31.00 ns | 30.00 ns |
5 | A1 and B3 | 41.5 ns | 36.50 ns | 37.00 ns | 45.00 ns |
6 | A2 and A3 | 27.00 ns | 30.00 ns | 40.00 ns | 40.00 ns |
7 | A2 and B1 | 37.00 ns | 40.00 ns | 40.00 ns | 40.00 ns |
8 | A2 and B2 | 12.00 |
10.00 |
10.00 |
10.00 |
9 | A2 and B3 | 17.00 |
10.00 |
10.00 |
30.00 ns |
10 | A3 and B1 | 43.00 ns | 39.00 ns | 50.00 ns | 50.00 ns |
11 | A3 and B2 | 39.5 ns | 31.50 ns | 17.00 |
18.00 |
12 | A3 and B3 | 43.00 ns | 32.00 ns | 19.00 |
40.00 ns |
13 | B1 and B2 | 32.5 ns | 19.00 |
17.00 |
18.00 |
14 | B1 and B3 | 36.00 ns | 19.00 |
19.00 |
40.00 ns |
15 | B2 and B3 | 46.50 ns | 49.5 ns | 41.50 ns | 26.00 ns |
Chi-Square | 11.63 | 18.46 | 24.93 | 19.45 | |
Df | 5 | 5 | 5 | 5 | |
Significance level | 0.040 | 0.020 | 0.000 | 0.002 |
The taste of Sample A3 (tef + 10% sorghum) was not significantly different from the taste of all the other injera prepared from
Texture is another important parameter often used to measure the quality of breads. It is determined by touch and refers to the degree of fluffiness, roughness, smoothness, hardness or softness. Out of the six samples, Sample A2 (tef + 5% sorghum added) was the most liked for texture, scoring a 100% positive (like) response, with the highest mean rating of 4.9, followed by Samples A1 (tef + 0% sorghum), A3 (tef + 10% sorghum), and B1 (
The appearance of injera is one of the most important parameters, which refers to the quality of the eyes (cells) of the honeycomb-like structure of the top surface of injera formed during cooking due to escaping CO2 bubbles (Yetneberk et al.,
Overall acceptability refers to the combinations of evaluations by consumers or panelists of a product. In this experiment, results showed that there was a statistically significant difference (
Taking all sensory attributes into account, though there was a statistically significant difference among samples, all blends scored a mean rating well above average (Table
The present study revealed that grains of
The idea of testing the grains of
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
The authors are grateful to Mr. Charles Wessels (tef farmer and owner of the tef stone-mill in Bloemfontein, South Africa) for his assistance in grinding the